tag:theconversation.com,2011:/uk/topics/rodents-26413/articlesRodents – The Conversation2024-03-14T12:43:43Ztag:theconversation.com,2011:article/2196872024-03-14T12:43:43Z2024-03-14T12:43:43ZCity mouse or country mouse? I collect mice from Philly homes to study how they got so good at urban living<figure><img src="https://images.theconversation.com/files/576250/original/file-20240216-24-90lbyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">European colonizers brought mice to the Americas, where they squeaked out a comfortable life.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/mouse-peeking-out-of-the-hole-royalty-free-image/525023427">Dejan Kolar/iStock Collection via Getty Images Plus</a></span></figcaption></figure><p>Dusty barns, gleaming stables and damp basements. These are all places where you might find a house mouse – or a member of my research team. </p>
<p>I’m an <a href="https://scholar.google.com/citations?user=DMxMLmwAAAAJ&hl=en">evolutionary biologist</a>, and my lab at Drexel University studies wild house mice. With help from Philly residents, we are collecting mice from high-rises and row homes to learn more about the impacts of city living on house mice. In short, we want to know whether there is any scientific basis to <a href="https://sites.pitt.edu/%7Edash/type0112.html#aesop">“The Town Mouse and the Country Mouse” fable</a> in which the cousins eat differently based on where they live.</p>
<p><a href="https://www.npr.org/2023/07/26/1190071137/its-hot-out-there-a-new-analysis-shows-its-much-worse-if-youre-in-a-city">Cities are hotter</a> and they have a lot of people living in high densities, which means more trash and usually more pollution. This can affect how <a href="https://www.doi.org/10.1126/science.aam8327">species that live in cities evolve</a>. Cities are also dominated by artificial habitats such as sidewalks, high-rises and subways rather than open fields and forests. </p>
<p>We are interested in many possible changes, but especially in whether the many differences between urban and rural environments translate into genetic differences between city mice and country mice, such as which versions of genes related to metabolism are more common. </p>
<p>To find the answers, we sequence the mice’s genomes. With that data, we can answer a variety of questions, such as: Are city mice more or less genetically diverse than country mice? Are there regions of DNA, the molecule that encodes genetic information, that are consistently different between urban and rural mice? If so, what are the functions of genes in those regions? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration of two mice from a translation of Aesop's Fables published in 1912." src="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Just how different are city mice and country mice? Researchers are studying their guts and genes to find out.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Rackham_town_mouse_and_country_mouse.jpg">Arthur Rackham, public domain via Wikimedia Commons</a></span>
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<h2>Why study house mice?</h2>
<p>One reason we study house mice is because they are so widespread. European colonizers <a href="https://doi.org/10.1093/g3journal/jkac332">brought house mice to the Americas</a> around 500 years ago. The rodents have now spread into many different climates and habitats across North and South America in most places that humans live, including Philadelphia. </p>
<p>Though small in size, house mice have made immeasurable <a href="https://shop.elsevier.com/books/the-mouse-in-biomedical-research/fox/978-0-12-369456-0">contributions to genetics and medicine</a>. They are mammals like humans, but house mice reproduce quickly and are relatively easy to breed and maintain. In fact, part of why scientists adopted mice early on as a model system is because people were already breeding “<a href="https://doi.org/10.7554/eLife.05959">fancy mice</a>” as pets. As a result, methods for keeping and breeding them were known.</p>
<p>Mice have many visible traits for geneticists to study. My team wants to know more about the genes and traits that have contributed to their ability to thrive in a variety of environments. The work we do with wild house mice also feeds back into work with laboratory mice and biomedical research. The house mice found in attics and cabinets are the same species that are studied in labs, but they are <a href="http://doi.org/10.1038/ng.847">more genetically diverse</a> than laboratory strains. Our project will generate whole genome sequences from many wild mice, and that data can help scientists who study traits and diseases. </p>
<h2>Tips for catching mice</h2>
<p>I previously worked on a large project studying <a href="https://doi.org/10.1371/journal.pgen.1007672">how house mice have adapted to different climates</a> in the Americas. For that project, I went to many, many farms throughout the eastern United States and became very good at catching mice in barns. </p>
<p>Starting this project with a focus on cities was a new challenge. First, our team had to find Philly residents who wanted us to trap their mice. We spent a lot of time spreading the word on social media, talking to friends and posting flyers. </p>
<p>We talked to many Philadelphians who were frustrated with trying to rid their homes of mice. Some had videos of house mice avoiding the traps they had set or stealing the bait and running away. We share this frustration and feel it keenly. In some cases, it took us many days to catch a single mouse in an apartment.</p>
<p>Part of the reason is because many Philadelphia houses are old. This means they are often full of character – and holes that give mice great places to hide. Luring the mice out of their nests and into our traps is difficult. We had the most success with peanut butter bait, which has a strong and very appealing odor for mice. But mice are omnivores, eating a diverse diet that includes insects. We have heard many stories from community members who used bait such as chocolate, cereal, cookies and even bacon bits. </p>
<h2>What’s next</h2>
<p>We hope to start sharing results over the next two years. We are working in three cities – Philadelphia, New York City and Richmond, Virginia – and have completed our first collections. Now we need to generate and analyze genetic data, so we are very busy in the lab. </p>
<p>We are extracting DNA, as well as another form of genetic material called RNA, from different tissues. With the DNA we will study how much genetic variation exists within city mouse populations, and whether there are genetic differences between urban and rural mice. The RNA will help us understand how differences in DNA translate into differences in metabolism, physiology and other cellular processes. </p>
<p>We will also look to see whether there are differences in traits. For example, we will measure their skulls and skeletons. We will sequence the DNA of the microbes in their digestive system to learn about their gut microbiomes, the collection of bacteria that live in their digestive system, and use <a href="https://www.futurelearn.com/info/courses/archaeology/0/steps/15267">stable isotope analysis</a> to identify any differences in their diets. Stable isotope analysis of diet uses the ratios of naturally occurring atoms of elements such as carbon and nitrogen to determine what types of food an organism has eaten.</p>
<p>Cities are full of wildlife. Learning about how cities shape the evolution of mice may help us find better ways to manage mouse populations and other urban wildlife while also better understanding evolution.</p><img src="https://counter.theconversation.com/content/219687/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Megan Phifer-Rixey receives funding from the National Science Foundation (NSF CAREER 2332998 Division of Environmental Biology).
</span></em></p>An evolutionary biologist is studying what these resilient urban pests can teach us about adaptation and evolution.Megan Phifer-Rixey, Assistant Professor of Biology, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207472024-02-20T13:19:08Z2024-02-20T13:19:08ZMurderous mice attack and kill nesting albatrosses on Midway Atoll − scientists struggle to stop this gruesome new behavior<figure><img src="https://images.theconversation.com/files/575113/original/file-20240212-18-ff3txe.png?ixlib=rb-1.1.0&rect=0%2C5%2C3968%2C2964&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Their 'island naïveté' means these seabirds are easy pickings when mice attack.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/usfwspacific/37343873514/in/album-72157688010783584/">USFWS - Pacific Region/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>At the far end of the Northwestern Hawaiian Islands lies Kuaihelani – also known as Midway Atoll – a small set of islands home to the world’s largest albatross colony. <a href="http://datazone.birdlife.org/species/factsheet/laysan-albatross-phoebastria-immutabilis/text">Over a million albatrosses</a> return to Kuaihelani each year to breed. These seemingly pristine islands appear safe, but there’s a predator lurking among the seabirds. </p>
<p>House mice (<em>Mus musculus</em>) — the same kind that may be in your residence — have started to attack and kill albatrosses, eating them alive as they sit on their nests. <a href="https://scholar.google.com/citations?hl=en&user=w5r9C28AAAAJ">I’m an ecologist</a> who’s been studying the mystery behind these murderous mice.</p>
<h2>A predator hiding in plain sight</h2>
<p>Once the site of intense <a href="https://www.history.navy.mil/browse-by-topic/wars-conflicts-and-operations/world-war-ii/1942/midway.html">warfare during World War II</a>, Kuaihelani is now a <a href="https://www.fws.gov/refuge/midway-atoll">national wildlife refuge</a>. </p>
<p>Without predators such as cats, rats or mongooses, Kuaihelani provides a safe haven for millions of nesting and migratory birds, including mōlī (<em>Phoebastria immutabilis</em>), also known as <a href="https://abcbirds.org/bird/laysan-albatross/">Laysan albatrosses</a>. These seabirds, each about the size of a goose, nest in nearly the exact same spot each year, producing only one egg annually. </p>
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<a href="https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One person holds a large bird while another, wearing medical gloves, inspects a bloody wound on its back." src="https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575991/original/file-20240215-26-727clu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Biologists examine wounds on an adult mōlī caused by invasive house mice.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usfwspacific/37090466503/in/album-72157688010783584/">USFWS - Pacific Region/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>In the winter nesting season of 2015, bird-counting volunteers and biologists began seeing gruesome bloody wounds on nesting mōlī. At first, they found only a few mōlī with these mysterious injuries, which included severe chewing along the neck and even scalping. In the weeks that followed, they found dozens of injured mōlī, then hundreds.</p>
<p>Biologists were stumped. Had a black rat escaped off a docked boat? Had a peregrine falcon blown in with the latest winter storm? Desperate to identify the culprit, biologists set up game cameras around nesting mōlī. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/R_go6iU3txg?wmode=transparent&start=72" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Time-lapse night vision footage shows a mouse attacking the head and body of a nesting mōlī.</span></figcaption>
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<p>The cameras captured bizarre nighttime footage of mice crawling and chewing on the backs and heads of mōlī. It was the first time a house mouse had ever been observed <a href="https://doi.org/10.7589/JWD-D-20-00065">attacking a live adult, nesting albatross</a>. </p>
<p>Mōlī, like many seabirds, have evolved without predators on remote islands. As a result, such seabirds are often oddly unafraid and curious – pulling on researchers’ shoelaces or nibbling at our clipboards. This phenomenon is called “<a href="https://doi.org/10.1093/acprof:osobl/9780199735693.001.0001">island naïveté</a>” and, however charming, can spell disaster when nonnative predators such as rats and cats are introduced to islands. Lacking innate caution, even the largest seabirds can become the defenseless prey of predators as small as a mouse.</p>
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<a href="https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white aerial photo of two small island. The one in the foreground has three intersecting landing strips." src="https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=640&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=640&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=640&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=804&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=804&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576029/original/file-20240215-26-vs2u2p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=804&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The World War II military base on Midway Atoll including an airfield on Eastern Island and more facilities on Sand Island, across the channel.</span>
<span class="attribution"><a class="source" href="https://en.m.wikipedia.org/wiki/File:Aerial_view_of_Midway_Atoll_on_24_November_1941_(80-G-451086).jpg">U.S. Navy/Wikimedia Commons</a></span>
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<h2>Developing a taste for flesh</h2>
<p>During World War II, the islands of Kuaihelani were cleared and covered with <a href="https://scholarspace.manoa.hawaii.edu/bitstreams/6e831988-862b-4eff-a3a3-e08e59e1e2db/download">wartime infrastructure</a>. Both black rats and house mice were <a href="https://doi.org/10.2307/1364149">inadvertently introduced</a> at this time. Soon, the rats began decimating populations of <a href="https://www.jstor.org/stable/27639258">burrowing seabirds</a>.</p>
<p>When the military importance of Kuaihelani faded in the 1990s, management of the atoll was transferred to the <a href="https://www.fws.gov/refuge/midway-atoll">U.S. Fish and Wildlife Service</a>. Rats were successfully <a href="https://www-jstor-org.utk.idm.oclc.org/stable/1521854">eradicated in 1996</a>, but mice remained. Thought to be small and harmless, they didn’t generate much concern <a href="https://library.sprep.org/sites/default/files/control-house-mice-preying-adult-albatrosses-midway-atoll-national-wildlife-refuge.pdf">until 2015</a>. </p>
<p>Although scientists may never know exactly why mice began to attack and kill mōlī, we have some ideas. </p>
<p>Due to climate change, Kuaihelani has experienced increasingly erratic precipitation, sometimes resulting in <a href="https://pubs.usgs.gov/of/2012/1182/of2012-1182.pdf">long dry spells or intense downpours</a>. During dry periods, vegetation quickly dies back. It’s likely the usual food items for mice, namely seeds and bugs, decline during these periods. In order to survive, mice need to find a different food source. </p>
<p>On an island with millions of birds, seabird carcasses are plentiful and attract a rich community of bugs, including <a href="https://doi.org/10.1371/journal.pone.0293092">cockroaches, isopods and maggots</a>. Mice appear to have quite an appetite for these critters and likely feed on seabird carcasses at the same time. The transition from scavenging dead seabirds to attacking live ones that don’t fight back is only a small step. </p>
<p>As mouse attacks on nesting mōlī escalated from 2015 on, it was clear something needed to be done – and fast. The solution was to get rid of the mice, which, unfortunately, is much easier said than done. </p>
<h2>Die-hard mice</h2>
<p>Mouse eradication is a challenging and risky conservation endeavor that requires years of <a href="https://doi.org/10.1016/j.biocon.2014.10.014">research and careful planning</a>. Ideally, rodenticide, a type of poison used to kill rodents, should be offered when mice are most hungry and likely to eat it. This requires knowing exactly what they are eating and when those food sources are scarce.</p>
<p>By extracting and sequencing DNA from mouse poop and analyzing stable isotopes – a technique that identifies unique chemical fingerprints of organisms – my colleagues and I could figure out <a href="https://doi.org/10.1371/journal.pone.0293092">what organisms mice were eating and in what quantities</a>. We found that mice on Sand Island of Kuaihelani mainly eat bugs (about 62% of their diet), followed by plants (27%) and finally albatross (likely mōlī, about 12%). The Fish and Wildlife Service identified July as the best time for the eradication attempt, since seabird density is typically lowest then. </p>
<p>Because of COVID-19 disruptions, the eradication attempt was delayed until July 2023, when the nonprofit organization <a href="https://www.islandconservation.org/">Island Conservation</a> and the Fish and Wildlife Service meticulously applied rodenticide in multiple rounds. At first, it seemed to be working. But in the weeks that followed, a few mice were spotted – then more. By September 2023, the eradication was declared <a href="https://www.fws.gov/project/midway-atolls-seabird-protection-project">unsuccessful</a>.</p>
<p>Some conservation practitioners believe eradication should be <a href="https://www.fws.gov/project/midway-atolls-seabird-protection-project">attempted again</a>, but others worry about <a href="https://doi.org/10.1016/j.scitotenv.2023.166290">creating mice resistant to rodenticide</a>. When generations of rodents are exposed to rodenticide repeatedly, they may start to carry genetic mutations resulting in <a href="https://guide.rrac.info/introduction.html">resistance to the poison</a>, making future eradication efforts ineffective. </p>
<p>Without a doubt, mice on Kuaihelani have already been exposed to rodenticide for a long time. When Kuaihelani – or Midway Atoll – was a naval base, rodenticide was likely applied in and around buildings and residences. The rat eradication in 1996 was another exposure. I’m currently researching whether the mice on Kuaihelani already have these genetic mutations. </p>
<p>The worries about rodenticide-resistant mice aren’t limited to Kuaihelani. Around the world, <a href="https://doi.org/10.1002/ps.7261">especially in Europe</a>, there are more and more cases of rodents carrying resistance. Rodents continue to have severe and widespread ecological effects <a href="https://doi.org/10.1007/s10530-008-9401-4">on islands worldwide</a>.</p>
<p>For now, I’m focused on helping the mōlī of Kuaihelani survive. But our research may also help inform the growing challenge of resistant mice around the world.</p><img src="https://counter.theconversation.com/content/220747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wieteke Holthuijzen received funding for research from the National Science Foundation Graduate Research Fellowship Program, Northern Illinois University, Sigma Xi, and Island Conservation. She is affiliated with the University of Tennessee, Knoxville and has collaborated with the U.S. Fish and Wildlife Service and Island Conservation. </span></em></p>On a small, remote island in the Pacific Ocean, an unlikely predator feasts on the world’s largest albatross colony. Researchers are trying to figure out how to stop these murderous mice.Wieteke Holthuijzen, Ph.D. Candidate in Ecology and Evolutionary Biology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196082024-02-01T01:20:54Z2024-02-01T01:20:54ZWhy don’t people care about Australia’s native rodents? The problem could be their ugly names<figure><img src="https://images.theconversation.com/files/572624/original/file-20240131-27-a8bm32.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C3053%2C2148&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spinifex hopping mouse, or Tarkawarra from the Pitjantjatjara language.
</span> <span class="attribution"><span class="source">Mike Gillam</span></span></figcaption></figure><p>The common names of Australian animals often originate in Aboriginal languages, and beneficially so. Continuing use of names such as kangaroo and kookaburra helps to honour the wealth of knowledge possessed by First Nations peoples, to appreciate the natural heritage of a place more deeply, and to naturalise English to this continent.</p>
<p>Some 30 years ago, I and colleagues published <a href="https://catalogue.nla.gov.au/catalog/722353">a paper</a> calling for this naming practice to extend to native rodents. This group of animals contains many handsome and fascinating animals among its many species. </p>
<p>But sadly, native rats and mice don’t usually evoke sympathy among the Australian public. The unappealing common names for the species – such as swamp rat or long-haired rat – do little to help the problem.</p>
<p>Public sentiment towards an animal matters. It can affect whether their habitat is protected, if they are prioritised for research and conservation, and the amount of funding devoted to protecting them. So among the many other good reasons to ascribe Aboriginal common names to our species, it might mean the difference between their survival and extinction.</p>
<figure class="align-center ">
<img alt="rat on stony ground in front of rock and leaves" src="https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572328/original/file-20240131-25-jlyswx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Names of species can influence their public standing. Pictured: the unfortunately named Australian swamp rat.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What’s in a name?</h2>
<p>Of the 60 Australian rodent species, <a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicthreatenedlist.pl">nearly 20</a> are extinct or greatly diminished in range. </p>
<p>As with other threatened mammals, desert-dwelling rodents have suffered most. For example among hopping mice, five of ten species are extinct. Those still remaining could do with our attention – and naming them may help.</p>
<p>Research has shown common names of species are an important tool when seeking to increase community support for conservation.</p>
<p>One <a href="https://doi.org/10.1080/10871209.2020.1753132">study</a> by Australian researchers analysed the common names of almost 27,000 animals from the IUCN Red List of threatened species. It found frequent words in animal common names that produced strong positive or negative sentiment.</p>
<p>Common words driving positive sentiment included “golden” and “great”. Words driving negative sentiment included “rat”, “lesser” and “blind”. </p>
<p>The research found many words were also associated with human emotions. For example, “dove” was associated with joy, anticipation and trust. “Rat” was associated with fear and disgust, probably due to its associations with disease, uncleanliness and deceitfulness, the study found.</p>
<p>The researchers said strategic name changes may improve public engagement and support for species and therefore provide effective, low-cost conservation benefits.</p>
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<h2>How about ‘pakooma’ and ‘palyoora’?</h2>
<p>So where might we find new, more appealing monikers for our maligned rodents? Our 1995 paper suggested selecting common names from relevant Aboriginal words that might readily be pronounced by English speakers. </p>
<p>At the time, we checked our document before publication with offices of the then-current Aboriginal and Torres Strait Islander Commission. Should Aboriginal words be used to rename species today, agreement should be sought from the relevant language group.</p>
<p>The brush-tailed rabbit-rat, <em>Conilurus penicillatus</em>, is an example of a rodent ripe for renaming. It’s a striking and vigorous animal of northern Australia, which became extinct in Kakadu National Park in the 2000s and <a href="https://www.nespthreatenedspecies.edu.au/projects/mitigating-cat-impacts-on-the-brush-tailed-rabbit-rat">now persists</a> in only a handful of isolated regions. How unfair it is that this splendid creature should be thought of as a mere rat – as well as bearing the nomenclatural burden of Australia’s worst vertebrate pest? Perhaps it could be renamed pakooma, from the East Arnhem languages.</p>
<p>Another sad example is provided by <em>Xeromys myoides</em>, an inhabitant of coastal swamps and mangroves. It is known as the false water rat, a name which could barely be improved upon if the aim is to demean. The animal could well be called yirrkoo, from the Kunwinjku/Mayali language.</p>
<p>And consider the graceful <em>Pseudomys australis</em>, an animal of the outback Channel Country in Queensland and South Australia. The species is of conservation concern, but public attention is hardly likely when the animal is called a plains rat. It deserves better – perhaps the lovely name palyoora, from the Wangkangurru language. </p>
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<strong>
Read more:
<a href="https://theconversation.com/ghost-rodents-get-ready-to-fall-in-love-with-australias-albino-rats-and-mice-201458">Ghost rodents: get ready to fall in love with Australia's albino rats and mice</a>
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<h2>The tide may be turning</h2>
<p>Back in the 1990s, our rodent-renaming initiative sank almost without trace. Only one Aboriginal name – rakali, from Murray River languages – took something of a hold, replacing the common name water rat (<em>Hydromys chrysogaster</em>). In the intervening years, two authors of the paper, Dick Braithwaite and John Calaby, have passed away. Time has moved on.</p>
<p>But there have been flickers of encouragement. Western Australia’s 1997 recovery plan for the Shark Bay mouse, <em>Pseudomys fieldi</em>, used the name djoongari (Luritja/Pintubi). When Tim Bonyhady in 2019 published his unusual and matchless book, The Enchantment of the Long-haired Rat: A Rodent History of Australia, he used the name mayaroo throughout (<em>Rattus villosissimus</em>, from Wangkangurru).</p>
<p>And now interest may be resurgent. In the Threatened Species Action Plan 2022–2032, federal environment authorities adopted names of Aboriginal origin wherever possible. This included antina (<em>Zyzomys pedunculatus</em>, central rock-rat, Arrernte), pookila (<em>Pseudomys novaehollandiae</em>, New Holland mouse, Bugila/Ngarigu), and woorrentinta (<em>Notomys aquilo</em>, northern hopping-mouse, from Lardil, the language of Mornington Island).</p>
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Read more:
<a href="https://theconversation.com/impressive-rafting-skills-the-8-million-year-old-origin-story-of-how-rodents-colonised-australia-189793">'Impressive rafting skills': the 8-million-year old origin story of how rodents colonised Australia</a>
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<figure class="align-center ">
<img alt="small furry rodent known as mayaroo" src="https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572611/original/file-20240131-19-2n8qa8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rattus villosissimus, or the long-haired rat, would be better named as mayaroo.</span>
<span class="attribution"><span class="source">Angus Emmott</span></span>
</figcaption>
</figure>
<h2>A timely, much-needed change</h2>
<p>Zoologists are rightly conservative about scientific naming conventions, in line with commitment to the principles of biological nomenclature. However, we are free to modify common names – and should, if there are good reasons to do so. </p>
<p>And so, 30 years after my colleagues and I first issued the call, Indigenous names for Australian rodents are commended to you once more. It is timely that the extensive Aboriginal knowledge of our continent be so honoured, that the wider culture be enriched – even if in such a tiny way – and that mayaroo and pookila should live in the English language.</p>
<p><em>The 1995 paper referred to in this article, Australian Names for Australian Rodents, was authored by R.W. Braithwaite, S.R. Morton, A.A. Burbidge and J.H. Calaby. It was published by the Australian Nature Conservation Agency, Canberra. With thanks to Andrew Burbidge, one of the original authors, for giving his blessing to this article.</em></p><img src="https://counter.theconversation.com/content/219608/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steve Morton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Native rats and mice don’t usually evoke sympathy among the Australian public. The common names for the species – such as swamp rat – do little to help.Steve Morton, Honorary Fellow, Charles Darwin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221422024-01-29T19:05:19Z2024-01-29T19:05:19ZStop killing brown snakes – they could be a farmer’s best friend<figure><img src="https://images.theconversation.com/files/571808/original/file-20240129-27-4fxoz7.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4245%2C2819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Many Australians who work outdoors – especially farmers and graziers – attempt to kill every snake they encounter, especially those thought to be venomous. In fact, <a href="https://www.jstor.org/stable/1565247">research</a> in one part of rural Australia found 38% of respondents tried to kill snakes wherever possible.</p>
<p>This attitude is misguided and dangerous. Despite their fearsome reputation, venomous Australian snakes pose little risk to human health. And snakes are hugely beneficial on farms by consuming pests such as rodents. </p>
<p><a href="https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/acv.12925">New research</a> by myself and colleagues estimated the magnitude of that benefit. We found adult eastern brown snakes can collectively remove thousands of mice per square kilometre of farmland each year, which substantially increases farm productivity. </p>
<p>Our study suggests the benefits of snake populations on agricultural land far outweigh the potential costs, and farmers should tolerate rather than kill them.</p>
<h2>A persecuted serpent</h2>
<p>Brown snakes are the most common deadly snake species found in disturbed agricultural habitats in the southern half of Australia. </p>
<p>The snakes are fast-moving and active during the day. Brown snakes are generally persecuted in rural areas because the danger of fatal snake bites is seen to outweigh their benefits as pest controllers.</p>
<p>It’s true that brown snakes are the <a href="https://www.researchgate.net/publication/320947425_Australia%27s_Dangerous_Snakes_Identification_Biology_and_Envenoming">most common</a> <a href="https://www.9news.com.au/national/eastern-brown-snakes-expert-reveals-what-makes-australias-deadliest-snake-so-lethal-what-to-do-if-bitten/9b454663-011e-4fa5-85a2-9d92888d0b30#:%7E:text=However%20according%20to%20statistics%20released,across%20most%20of%20eastern%20Australia.">cause</a> of fatal snake bite in Australia. But the bites are rarely fatal. Statistics show snakes of any species kill <a href="https://www.museum.qld.gov.au/learn-and-discover/animals-of-queensland/snakes#:%7E:text=Even%20dangerously%20venomous%20species%20pose,three%20snakebite%20deaths%20a%20year.">fewer than three</a> people per year in Australia, on average.</p>
<p><a href="https://www.flyingdoctor.org.au/qld/news/outback-survival-snakes-and-snakebites/">Around 3,000</a> snake bite cases are reported annually – a high proportion of which occur when a snake <a href="https://www.mja.com.au/journal/2017/207/3/australian-snakebite-project-2005-2015-asp-20">retaliates</a> to being attacked by a person.</p>
<p>Australian snakes, including brown snakes, <a href="https://researchers.mq.edu.au/en/publications/responses-of-free-ranging-brownsnakes-ipseudonaja-textilisi-elapi">generally retreat</a> rather than attack, even when provoked. Eastern brown snakes, in particular, tend to dwell in places where they are unlikely to be encountered by people. </p>
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Read more:
<a href="https://theconversation.com/good-luck-fella-stay-safe-a-snake-catcher-explains-why-our-fear-of-brown-snakes-is-misplaced-150783">'Good luck fella, stay safe': a snake catcher explains why our fear of brown snakes is misplaced</a>
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<h2>An upside to venomous snakes</h2>
<p>The most obvious benefit of maintaining brown snake populations is to reduce rodent numbers. Introduced species of rats and mice are a <a href="https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1005&context=nwrchumanconflicts">major cost</a> to Australian agriculture. In extreme cases, mice can destroy most or all of a crop.</p>
<p>We wanted to calculate the number of rodents removed from Australian farmland by brown snakes. </p>
<p>First, we drew on <a href="https://www.jstor.org/stable/3892162">work</a> I had done in the 1980s, which involved dissecting museum specimens to find out what proportion of brown snake diets consisted of rodents.</p>
<p>We then estimated the number of prey consumed each year by brown snakes. This was based on the feeding rates of captive snakes, data from commercially farmed pythons in farms in Thailand and Vietnam, and studies on a species of North American snake which is similar to brown snakes.</p>
<p>To estimate the abundance of brown snakes on farms, we consulted previous research on brown snake abundance, and rates of capture from fieldwork involving red-bellied black snakes. We also obtained data from the Atlas of Living Australia, an online compendium of information about the continent’s plants and animals.</p>
<p>Based on the combined data, we found a square kilometre of farmland can contain 100 adult eastern brown snakes, even where rates of encounters between people and those snakes are low. If each adult brown snake consumes around 100 wild mice each year – which is likely an underestimate – together this must equate to about 10,000 mice per square kilometre. Each mouse removed by a brown snake may eat several kilograms of grain crops over its life. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/4ITgdgPUMuY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<h2>Give snakes a chance</h2>
<p>Agricultural productivity gains are not the only benefits of tolerating brown snakes on farmland.</p>
<p>It would also allow a reduction in the use of chemical methods for rodent control, which can be expensive and ineffective. The chemicals can also threaten the <a href="https://escholarship.org/uc/item/8044n35x">health</a> of <a href="https://pubmed.ncbi.nlm.nih.gov/9759690/">humans</a>, livestock, scavenging wildlife and pets.</p>
<p>Tolerating brown snakes might also reduce the incidence of snake bite. <a href="https://www.qld.gov.au/environment/plants-animals/animals/living-with/snakes#:%7E:text=Snakes%20usually%20prefer%20to%20retreat,the%20snake%20to%20move%20away.">Most snake bites</a> are inflicted when people are trying to catch or kill the reptile.</p>
<p>What’s more, one study <a href="https://www.researchgate.net/publication/320947425_Australia%27s_Dangerous_Snakes_Identification_Biology_and_Envenoming">suggests</a> snakes that are long-term residents of an area are less agitated by close encounters with people and know the location of nearby safe havens, and so pose relatively little threat. Culling snakes may create an influx of new animals unfamiliar with the location and not used to humans.</p>
<p>The obvious rebuttal is that killing snakes reduces the incidence of future snake bite, by reducing overall snake numbers. However, data suggests this is not necessarily the case. For example, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158397">one study</a> in Indonesia showed reticulated pythons remained abundant despite millions of individuals being removed over decades.</p>
<p>Maintaining viable populations of snakes has an ecological benefit. Removing high-level predators destabilises food webs and disrupts the way ecosystems function.</p>
<p>Finally, conserving snakes has merit in its own right. Many species of snakes are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001371/#:%7E:text=Although%20there%20is%20little%20evidence,(Mullin%20%26%20Seigel%202009).">in decline</a>, including in Australia, and should be protected.</p>
<p>Our findings suggest the need for a more balanced view of the costs and benefits of snakes, including brown snakes. Tolerating them may bring benefits that outweigh the already low chance of life-threatening snake bite. </p>
<p><em>The author would like to acknowledge the contribution of Peter Mirtschin, Nathan Dunstan and Jeff Abraham to the research underpinning this article.</em></p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/new-research-reveals-these-20-australian-reptiles-are-set-to-disappear-by-2040-145385">New research reveals these 20 Australian reptiles are set to disappear by 2040</a>
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<p><em>Correction: A figure relating to mice per square kilometre has been amended from 1,000 to 10,000.</em></p><img src="https://counter.theconversation.com/content/222142/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rick Shine receives funding from the Australian Research Council. </span></em></p>The benefits of snake populations on agricultural land far outweigh the potential costs, and farmers should tolerate rather than kill them.Rick Shine, Professor in Evolutionary Biology, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2020422023-05-23T20:11:20Z2023-05-23T20:11:20ZHow to fool a mouse: ‘chemical camouflage’ can hide crops and cut losses by over 60%<figure><img src="https://images.theconversation.com/files/525305/original/file-20230510-15-ol6krl.jpg?ixlib=rb-1.1.0&rect=40%2C0%2C4500%2C2997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For as long as humans have grown our own food, we have battled pest animals that destroy crops and take food for themselves. </p>
<p>The traditional approach has been to try to kill the pests, typically with poisons. Too often, however, this fails to kill enough pests, harms native animals, and only minimally reduces damage.</p>
<p>We tackled this problem in a different way by asking: how do we stop hungry animals finding our crops in the first place?</p>
<p>In a <a href="https://www.nature.com/articles/s41893-023-01127-3">research paper published today</a>, we show how “chemical camouflage” can prevent house mice finding newly sown wheat seeds. The method reduced mouse damage to wheat crops by more than 60% even during plague conditions, without killing a single mouse. </p>
<h2>The rodent menace</h2>
<p>Rodents are responsible for an <a href="https://onlinelibrary.wiley.com/doi/10.1002/ps.1718">estimated 70 million tonnes of grain</a> lost worldwide each year. Even a 5% reduction in these losses could feed more than 280 million people.</p>
<p>In Australia, the 2021 mouse plague cost farmers in New South Wales alone upwards of $1 billion, according to an <a href="https://www.nswfarmers.org.au/NSWFA/Posts/Media_Releases/mr.39.21.aspx">industry association estimate</a>. A mouse plague occurs somewhere in Australia at least every four years. </p>
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Read more:
<a href="https://theconversation.com/no-one-ever-forgets-living-through-a-mouse-plague-the-dystopia-facing-australian-rural-communities-explained-by-an-expert-159339">‘No one ever forgets living through a mouse plague’: the dystopia facing Australian rural communities, explained by an expert</a>
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<p>Currently, the only management option to reduce mouse numbers is broad-scale baiting. However, baiting is often ineffective and has led to calls for more lethal poisons, which carry <a href="https://theconversation.com/mouse-plague-bromadiolone-will-obliterate-mice-but-itll-poison-eagles-snakes-and-owls-too-160995">major risks for native wildlife</a>. </p>
<p>The relationship between baiting effort and crop yield is not well understood, and mouse numbers typically crash in plague years even without intervention. A better approach is to focus on reducing mouse impacts, rather than mouse numbers.</p>
<h2>How to fool a mouse</h2>
<p>Mouse damage to Australia’s most valuable crop, wheat, occurs mostly in the two-week period between sowing and germination. During this time, mice are attracted to the smell of the wheat germ – the nutritious and fatty part of the seed – beneath the ground, and they learn to dig up seeds with pinpoint accuracy, leading to significant crop losses. </p>
<p>This led to our question: can we hide the seeds so mice can’t find them?</p>
<p>Like many animals, mice primarily use their sense of smell to find food. The world is full of odours, and hungry foragers must prioritise important smells and disregard useless ones. </p>
<p>When a food is too difficult to find, or an odour is not a useful indicator of food, foragers must <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2011.01817.x">give up and search for something else</a> to avoid wasting energy. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527159/original/file-20230519-23-shy35f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">How mice find wheat germ – and how camouflage can keep them away.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41893-023-01127-3">Parker et al. / Nature Sustainability</a>, <span class="license">Author provided</span></span>
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<p>Because hungry animals can’t afford to waste effort on odours that don’t lead to food, they are vulnerable to <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2534">olfactory misinformation and chemical camouflage</a>. As with visual camouflage, if the background, in this case smell, appears the same as the item we are trying to hide, the target item cannot be distinguished.</p>
<p>Animals can also learn about the usefulness of information, making them vulnerable to another form of misinformation – odour pre-exposure. By deploying food odours before food is available, foragers initially attracted to the odour repeatedly receive no reward and learn to ignore it. </p>
<p>When the food does become available, foragers don’t follow the odours because they know they’re unrewarding. We recently used this technique to dramatically improve nest survival for threatened shorebirds at risk from by predation by invasive predators in New Zealand.</p>
<h2>A test under tough conditions</h2>
<p>Until now, these techniques have been tested on relatively widely dispersed food items with fewer foragers over a larger area. Whether olfactory misinformation could protect a crop with more than 300 mice and 1.6 million seeds per hectare was unclear.</p>
<p>We worked on a 27-hectare wheat paddock in southwest NSW, using 60 plots to test our two olfactory misinformation techniques. We used wheat germ oil to provide the odour background, as it is made from the part of wheat seeds that mice seek out and is a relatively cheap byproduct of the wheat-milling process. </p>
<p>Both techniques involved spraying a fine mist of wheat germ oil solution onto the plots. Each application was equivalent to the smell of around 50 times the number of seeds on the plot.</p>
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Read more:
<a href="https://theconversation.com/scientists-used-fake-news-to-stop-predators-killing-endangered-birds-and-the-result-was-remarkable-152320">Scientists used 'fake news' to stop predators killing endangered birds — and the result was remarkable</a>
</strong>
</em>
</p>
<hr>
<p>Our first technique, odour camouflage, began immediately after the crop was planted and was reapplied several times until seedlings appeared. This created a blanket of wheat odour to hide seeds from detection. </p>
<p>Our second technique, odour pre-exposure, had wheat germ oil applied six days before the wheat crop was planted and continued for the week after. We predicted that mice attracted to the odour before seeds were planted would begin to ignore wheat odour after repeatedly finding no seeds.</p>
<p>We also had three control treatments: one sprayed with canola oil to control for an oil effect, one we walked on without spraying to control for seed loss due to trampling, and one that remained totally untouched.</p>
<p>One and two weeks after sowing, we counted mouse damage in the form of diggings where seeds had been extracted by mice. After two weeks, we also estimated the number of seedlings that were lost to mice. The results were staggering.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of small holes dug in the ground among rows of grassy plants." src="https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525536/original/file-20230511-15-dajgjd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The scene of the crime: small holes dug by mice hunting for wheat seeds.</span>
<span class="attribution"><span class="source">Peter Banks</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>After two weeks, our camouflage and pre-exposure treatments had reduced mouse damage by 63% and 74% respectively, compared to the control. We also estimated that 53% and 72% fewer seedlings, respectively, were lost to mice on these plots. </p>
<p>The difference in the effect of pre-exposure to wheat odour and the effect of camouflage treatments was not statistically significant, and we concluded the camouflage effect is the most likely reason for the reduction in damage.</p>
<h2>Working with the animals</h2>
<p>In an increasingly populated world where food security is becoming a priority, we need new ways to tackle pest problems sustainably and safely. </p>
<p>Our methods are simple, safe and highly effective, even during a mouse plague. They carry no risks for native wildlife and involve no killing. Mice don’t go hungry either – they simply eat the foods they ate before the wheat was planted. </p>
<p>We believe simple behavioural interventions like ours, which work with animals’ motivations rather than against them, are the way of the future in wildlife management and conservation.</p>
<p>We believe this new approach has the potential to manage pest impacts without the side effects that come from using lethal pest control.</p><img src="https://counter.theconversation.com/content/202042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Finn Cameron Gillies Parker receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Catherine Price receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Jenna Bytheway receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Peter Banks receives funding from the Australian Research Council and The Hermon Slate Foundation. He is an external member of CSIRO's Rodent Research Advisory Panel </span></em></p>Rodents destroy around 70 million tonnes of grain each year. What if we could trick them into looking elsewhere for their food?Finn Cameron Gillies Parker, PhD candidate, University of SydneyCatherine Price, Discovery Early Career Research Fellow, University of SydneyJenna Bytheway, Senior Research Officer in Conservation Biology, University of SydneyPeter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1964062023-01-03T11:55:00Z2023-01-03T11:55:00ZIn defence of rodents – why healthy ecosystems need them<figure><img src="https://images.theconversation.com/files/500975/original/file-20221214-11-erpcz1.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2923%2C1999&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A grizzled giant squirrel, native to Sri Lanka.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-photo-black-yellow-sri-lankan-381103162">Martin Mecnarowski/Shutterstock</a></span></figcaption></figure><p>You might think you have the measure of the rodent family. Perhaps just the word “rodent” conjures images of invasive rats, those urban denizens accused of spreading pathogens and parasites, chewing through wires and spoiling food.</p>
<p>Most rodents are, in fact, more elusive and inhabit quiet corners of rainforests, mountains, deserts and rivers. These small mammals have filled a niche in nature for at least the last 56 million years, and from shrew-rats to true rats and hamsters to beavers, rodents play an important role in ecosystems worldwide.</p>
<p>Yet, a huge number of rodent species are on the brink of extinction. Eking out an existence in shrinking habitats and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.13368">under threat</a> from persecution, pollution and climate change, rodents are overwhelmingly neglected by research and funding that might help to protect them. We are three conservation scientists determined to show that this is a mistake – and change your mind about these misunderstood creatures.</p>
<h2>More than vermin</h2>
<p>Roughly <a href="https://www.earlham.ac.uk/articles/rodents-are-awesome-extreme-evolution">40%</a> of all mammal species are rodents. There are around 2,375 living species, spanning mice, rats, squirrels, hamsters, voles, porcupines, lemmings, beavers, chinchillas, chipmunks and more. The number of recognised rodent species is <a href="https://www.pnas.org/doi/10.1073/pnas.0812419106#T1">still growing</a> and at a seemingly faster rate than other mammal groups including bats, primates and carnivores. Between two comprehensive checklists of global mammal species produced in <a href="http://www.departments.bucknell.edu/biology/resources/msw3/browse.asp">2005</a> and <a href="https://www.mammaldiversity.org/">2018</a>, an <a href="https://academic.oup.com/jmammal/article/99/1/1/4834091#110453319">additional 371 rodents</a> were officially recognised.</p>
<p>New discoveries are often the result of genetic work that has identified multiple similar-looking species previously described as one. Nonetheless, from the 3g desert-dwelling jerboa to the 50kg semiaquatic capybara, rodents are a remarkably diverse bunch.</p>
<figure class="align-center ">
<img alt="A small mouse on a bramble branch with blackberries." src="https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500992/original/file-20221214-3859-2wlm5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dormice can hibernate for six months or longer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/common-dormouse-muscardinus-avellanarius-normandy-1618140283">Slowmotiongli/Shutterstock</a></span>
</figcaption>
</figure>
<p>This diversity allows rodents to play numerous roles in Earth’s ecosystems. Rodents have a hand (or rather, paw) in determining which <a href="https://www.frontiersin.org/articles/10.3389/fevo.2021.676572/full">plants propagate and where</a> by eating and dispersing their seeds. Beavers <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12220?saml_referrer">engineer entire ecosystems</a> with their dams which help to purify water systems and moderate floods and droughts, while burrowing kangaroo rats create subterranean habitats <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2011.01930.x">used by other wildlife</a>. Rodents are also an invaluable link in the food chain, sustaining predators which include birds of prey, wolves, snakes and even spiders.</p>
<p>We shouldn’t forget that humans have long benefited from relationships with rodents. Agoutis in South America are one of the few animal groups capable of cracking open the capsules of the Brazil nut fruit. By hoarding excess seeds, agoutis <a href="https://www.cambridge.org/core/journals/journal-of-tropical-ecology/article/abs/seed-dispersal-spatial-distribution-and-population-structure-of-brazilnut-trees-bertholletia-excelsa-in-southeastern-amazonia/BA322CCB709B0BF6E53812C09EE311C0">help disperse their trees</a> throughout the Amazon rainforest and support the global production of Brazil nuts, which is almost entirely dependent on wild harvests. <a href="https://theconversation.com/rise-of-the-super-rat-rodents-detect-landmines-sniff-out-tb-find-disaster-victims-22272">African giant pouched rats</a> can detect tuberculosis in saliva, hidden land mines, survivors trapped under rubble and pangolins smuggled in shipping containers. By studying the <a href="https://theconversation.com/meet-the-naked-mole-rat-impervious-to-pain-and-cancer-and-lives-ten-times-longer-than-it-should-118809">resistance of naked mole-rats to cancer</a>, scientists hope to improve our understanding of the disease and its potential treatment. It’s clear that the loss of a rodent species – even the smallest – can have cascading consequences for humans and the environment.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/GBqMJjfSgYY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Underfunded, understudied and disappearing</h2>
<p>Worryingly, at least 15% of rodent species are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.13368">threatened with extinction</a>. More than 100 are among the top 560-ranked Evolutionarily Distinct and Globally Endangered (<a href="https://www.edgeofexistence.org/science/">EDGE</a>) mammals, meaning that while they are threatened, they also have few or no close relatives. If an EDGE species were to disappear, there would be nothing really like them left. </p>
<p>For many more species, scientists simply don’t know enough to understand how they are faring: the population trend (whether they are stable, declining or increasing) of at least a thousand rodents is unknown. Even when it comes to zoonotic disease, there are <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/cobi.13763?saml_referrer">substantial gaps in our knowledge</a> of viruses in rodents and how outbreaks might be influenced by their ecology or population dynamics. The reality is that rodents receive very little scientific attention beyond their discovery and naming.</p>
<p>Rodents are a hard sell outside science too. Studies on the public perception of wildlife demonstrate that rodents are generally <a href="https://www.sciencedirect.com/science/article/pii/S1617138116300917">the least favoured group</a>. Compared to larger-bodied mammals, rodents and small mammals are referred to on Twitter <a href="https://link.springer.com/article/10.1007/s10531-014-0629-2">substantially less</a>, not considered as <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/zoo.20316">interesting</a> by zoo visitors and <a href="https://journal.ipb.ac.id/index.php/konservasi/article/view/36902">inspire fewer donations</a> to conservation schemes. Even the bigger rodents such as beavers are <a href="https://www.sciencedirect.com/science/article/pii/S1617138110000026#aep-section-id9">outranked</a> by large carnivores, birds, moths and bees in public preference surveys.</p>
<figure class="align-center ">
<img alt="A beaver in water gnawing on a branch." src="https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500974/original/file-20221214-3885-pkk4by.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Even beavers can’t beat the anti-rodent bias.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/wet-eurasian-beaver-eating-leaves-swamp-2061899207">WildMedia/Shutterstock</a></span>
</figcaption>
</figure>
<p>It is no surprise then that some species have already fallen through the cracks. The <a href="https://www.iucnredlist.org/species/9003/22186735">little Swan Island hutia</a>, a rodent once endemic to Caribbean islands of the same name, was driven to extinction in 1960 by introduced cats. <a href="https://www.iucnredlist.org/species/10946/160756258">The Candango mouse</a> disappeared during a similar period in central Brazil, where its forest habitat was almost entirely paved over. Australia’s <a href="https://www.bbc.co.uk/news/world-australia-47300992">Bramble Cay melomys</a> was declared extinct as recently as 2016 after rising sea levels gradually degraded the tiny coral island on which it lived. The loss of this rodent is thought to be the first modern mammal extinction caused by climate change.</p>
<p>Some rodents remain unstudied for so long that it’s not known whether they still exist. Gould’s mouse, a species also native to Australia, was thought to be extinct for 150 years before it was <a href="https://www.theguardian.com/world/2021/jun/29/native-mouse-believed-to-be-extinct-for-150-years-found-off-western-australia">recently rediscovered</a> surviving on islands off of western Australia. Another, the Namdapha flying squirrel, was thought to be extinct in the wild until a single specimen was collected in 1981 from northeast India. The species is now listed as critically endangered and is currently known only from informal sightings dated decades ago. Of the world’s rediscovered species, the data shows that rodents remain missing for <a href="https://www.sciencedirect.com/science/article/pii/S0006320711000991">the longest time</a>, probably because there are not enough people looking for them.</p>
<p>Even well-monitored or well-known rodents aren’t safe. The common hamster is listed as critically endangered, and could die out in coming decades unless its decline is reversed. Its popular pet cousin, the golden (or Syrian) hamster, is also endangered in the wild, clinging on to its last fragment of habitat.</p>
<p>Many rodents can adapt well to landscapes altered by people, but others cannot adjust to this rat race and exist only in dwindling and deteriorating wildernesses. It is likely that we have already lost many species which we never even knew existed.</p>
<p>The first step towards recovering many threatened yet overlooked species may be to alter our own perceptions and behaviour. For the little guys like rodents, this means appreciating that even though they are perhaps not as glamorous or mighty as many flagship conservation species, we are far more dependent on their biodiversity than we might imagine.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/196406/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abi Gazzard works for the IUCN SSC Small Mammal Specialist Group (SMSG), which has received funding from Re:wild. Her research role is hosted by Durrell Wildlife Conservation Trust. </span></em></p><p class="fine-print"><em><span>Connor Panter received funding from the Ernest Kleinwort Charitable Trust.</span></em></p><p class="fine-print"><em><span>Ros Kennerley works for the IUCN SSC Small Mammal Specialist Group (SMSG), which has received funding from Re:wild. Her research role is hosted by Durrell Wildlife Conservation Trust.</span></em></p>Rodents are the most numerous – and least studied – of all Earth’s mammals.Abi Gazzard, Programme Officer, SSC Small Mammal Specialist Group, International Union for the Conservation of NatureConnor Panter, PhD Candidate in Macroecology and Biogeography, University of NottinghamRosalind Kennerley, Co-Chair of the IUCN SSC Small Mammal Specialist Group, International Union for the Conservation of NatureLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1897932022-09-02T21:45:34Z2022-09-02T21:45:34Z‘Impressive rafting skills’: the 8-million-year old origin story of how rodents colonised Australia<figure><img src="https://images.theconversation.com/files/482410/original/file-20220902-18492-69v2n4.jpg?ixlib=rb-1.1.0&rect=14%2C5%2C1902%2C1270&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A hopping mouse from the arid desert of Australia (Notomys). Hopping mice have evolved highly efficient kidneys to deal with the low water environments of Australia's deserts.</span> <span class="attribution"><span class="source">David Paul/Museums Victoria</span></span></figcaption></figure><p>A single, pregnant rodent floating on driftwood across the treacherous waters between Asia and New Guinea 8.5 million years ago may be behind the eventual colonisation of native rodents in Australia, our <a href="https://www.sciencedirect.com/science/article/pii/S0960982222012982?dgcid=author">new research</a> suggests.</p>
<p>Today, Australia has more than 60 species of native rodents found nowhere else in the world. When you count their close relatives across New Guinea and island neighbours, there are over 150 species. These include the rakali, an otter-like rodent with webbed feet, and desert hopping mice that get around like tiny kangaroos.</p>
<p>Until now, we’ve had an incomplete picture of how there came to be so many species. Our new research unites genomic sequencing and museum collections to reconstruct the evolutionary tale of native rodents, including many extinct and elusive species – and they have a fascinating origin story. </p>
<p>Native rodents have also suffered the highest rate of recent extinction of any mammal group in Australia, with 11 mainland species declared extinct since European colonisation in 1788. Many surviving native rodents remain at serious risk of extinction, with urgent conservation action needed to secure their future.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482404/original/file-20220901-9301-psbzi8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The semi-aquatic rakali (<em>Hydromys chrysogaster</em>) is a native rodent distributed across New Guinea and Australia. Rakali are part of the Hydromys Division, a group that has colonised Australia from New Guinea at least twice in the last million years.</span>
<span class="attribution"><span class="source">David Paul/Museums Victoria</span></span>
</figcaption>
</figure>
<h2>New methods, old specimens</h2>
<p>We extracted and sequenced DNA from museum specimens collected up to 180 years ago to unlock the secrets of the most elusive species. </p>
<p>In one case, we sequenced DNA from a specimen of Guadalcanal rat from the Solomon Islands collected over 130 years ago. The Guadalcanal rat was last seen alive when these specimens were collected in the 1880s, and hasn’t been recorded since. </p>
<p>It’s listed as <a href="https://www.iucnredlist.org/species/22805/22446647">critically endangered</a>, and is very possibly already extinct. </p>
<p>Like the Guadalcanal rat, every single specimen we studied has its own fascinating history. Together, they tell an 8-million-year long evolutionary story.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482407/original/file-20220902-16-7j7ogo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This is a specimen of Gould’s mouse from the Natural History Museum in London.</span>
<span class="attribution"><span class="source">Trustees of the Natural History Museum London/C. Ching</span></span>
</figcaption>
</figure>
<p>The genetic relatedness of distant rodent relatives tells us the ancestor of Australia’s native rodents originated in southeast Asia. There’s never been a land connection between Asia and New Guinea, and so we know this must happened via over-water colonisation – possibly on a piece of driftwood.</p>
<p>Our research dates this event to around 8.5 million years ago. Both New Guinea and Australia looked very different back then.</p>
<p>In contrast to the large and high-elevation island of modern New Guinea, 8.5 million years ago it was likely made up of a series of smaller, disconnected islands.</p>
<p>Our results show the earliest arriving rodent ancestors, probably tropical forest specialists, initially spread across this earlier New Guinea. But they then stayed put for 3.5 million years.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-adorable-mouse-was-considered-extinct-for-over-100-years-until-we-found-it-hiding-in-plain-sight-160930">This adorable mouse was considered extinct for over 100 years — until we found it hiding in plain sight</a>
</strong>
</em>
</p>
<hr>
<h2>A shared evolutionary story</h2>
<p>Around 5 million years ago, New Guinea experienced a big geological change. Tectonic activity triggered the uplift of an impressive mountain range through the centre of New Guinea, and led to the formation of expansive lowlands. </p>
<p>This expansion opened new environments for rodents to adapt to, and increased connectivity between New Guinea, Australia, and neighbouring islands.</p>
<p>From there, things really took off.</p>
<p>Rodent ancestors first arrived from New Guinea into Australia around 5 million years ago, probably via a land bridge exposed during a period of low sea level.</p>
<p>In Australia, they have adapted to many new environments including the harsh arid desert. In the last few million years, rodents have been especially mobile – repeatedly moving between New Guinea, Australia and neighbouring island archipelagos, generating many new species in the process.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=574&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=574&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482406/original/file-20220902-17818-9rbk6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=574&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Native rodents first arrived to New Guinea from Asia 8.5 million years ago, and then arrived to Australia 5 million years ago. Over the past few million years, they also have spread across the Solomon and Maluku Island archipelagos.</span>
</figcaption>
</figure>
<p>In our region alone rodents have transitioned between different geographic areas or islands at least 24 independent times in the past 5 million years. </p>
<p>Quite often, this has happened via over-water colonisation. Just like their ancestor, who crossed the waters from southeast Asia 8.5 million years ago, native rodents have continued to leverage their impressive rafting skills.</p>
<p>And yet, despite this remarkable flexibility across evolutionary time, native rodents have not been able to tolerate the dramatic changes to their environment that have occurred in the past 200 years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-epic-550-million-year-story-of-ulu-u-and-the-spectacular-forces-that-led-to-its-formation-167040">The epic, 550-million-year story of Uluṟu, and the spectacular forces that led to its formation</a>
</strong>
</em>
</p>
<hr>
<h2>Protecting native rodents</h2>
<p>Since 1788, we’ve lost 11 native rodent species to extinction. These include the <a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=131">white-footed rabbit-rat</a> and the <a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=136">lesser stick-nest rat</a>, once common on the Australian landscape.</p>
<p>Native rodents are particularly susceptible to predation by feral cats and foxes, land clearing, competition with pest rodents, and introduced disease. These ongoing threats place surviving species at serious risk of extinction. </p>
<p>One of Australia’s most critically endangered mammals, the central rock-rat, is on the brink of extinction after extensive habitat loss and predation by cats and foxes. <a href="https://www.australianwildlife.org/central-rock-rat-australias-most-endangered-mammal-airlifted-to-safe-refuge/">Captive breeding programs</a> are underway to boost population numbers.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482405/original/file-20220901-18063-yco9vc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A smoky mouse (<em>Pseudomys fumeus</em>) in the Grampians-Gariwerd National Park, Victoria, Australia. The smoky mouse is part of an evolutionary group that originated after colonisation of Australia from New Guinea around 5 million years ago, and is currently endangered after suffering population declines.</span>
<span class="attribution"><span class="source">David Paul/Museums Victoria</span></span>
</figcaption>
</figure>
<p>We know even less about the conservation status of many species in New Guinea, the Solomon Islands and Maluku Islands. </p>
<p>By combining genetic data from both modern and historical specimens, our <a href="https://doi.org/10.1016/j.cub.2022.08.021">new research</a> takes stock of the diversity of native rodents, and will help to define and prioritise species for conservation efforts.</p>
<p>By understanding how our native rodents evolved, we can make more informed decisions about how best to protect them into the future. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/death-by-irony-the-mystery-of-the-mouse-that-died-of-smoke-inhalation-but-went-nowhere-near-a-fire-139906">'Death by irony': The mystery of the mouse that died of smoke inhalation, but went nowhere near a fire</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/189793/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emily Roycroft receives funding from the Australian Government Research Training Program, the Dame Margaret Blackwood Soroptimist Scholarship, the Alfred Nicholas Fellowship (University of Melbourne), and the Holsworth Wildlife Research Endowment. This project received funding from Bioplatforms Australia through the Australian Government National Collaborative Research Infrastructure Strategy, via the Oz Mammals Genomics Initiative.</span></em></p>Australia has more than 60 species of native rodents found nowhere else in the world. New research used museum specimens to find out how they got here.Emily Roycroft, Postdoctoral Research Fellow, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1868932022-08-03T12:10:42Z2022-08-03T12:10:42ZCoyotes are here to stay in North American cities – here’s how to appreciate them from a distance<figure><img src="https://images.theconversation.com/files/476377/original/file-20220727-15-49bdtr.jpg?ixlib=rb-1.1.0&rect=42%2C0%2C4752%2C3151&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A coyote on a golf course in Scottsdale, Ariz., June 19, 2011.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/9UXnkz">Dru Bloomfield/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Coyotes have become <a href="https://doi.org/10.3897/zookeys.759.15149">practically ubiquitous</a> across the lower 48 United States, and they’re increasingly turning up in cities. The draws are <a href="https://urbancoyoteresearch.com/sites/default/files/resources/ecologycoyotes.pdf">abundant food and green space</a> in urban areas. </p>
<p>At first these appearances were novelties, like the hot summer day in 2007 when a coyote wandered <a href="https://abcnews.go.com/US/story?id=3005523&page=1">into a Chicago Quiznos</a> sub shop and jumped into the beverage cooler. Within a few years, however, coyote sightings became common in <a href="https://narratively.com/tracking-the-great-coyote-invasion-of-nyc/">the Bronx and Manhattan</a>. In 2021 a coyote strolled into a <a href="https://www.usatoday.com/story/news/nation/2021/08/22/coyote-in-classroom-los-angeles-back-to-school/8235396002/">Los Angeles Catholic school</a> classroom. They’re also appearing in <a href="https://www.theglobeandmail.com/canada/article-more-coyotes-are-adapting-to-urban-areas-in-canada-heres-why-they/">Canadian cities</a>.</p>
<p>People often <a href="https://www.rmotoday.com/local-news/study-investigates-fear-of-coyotes-1567946">fear for their own safety</a>, or for their <a href="https://www.wkyc.com/article/news/local/verify/verify-how-likely-is-a-coyote-to-attack-a-small-child-in-northeast-ohio/95-522589979">children</a> or <a href="https://thebark.com/content/are-you-afraid-coyotes">pets</a>, when they learn about coyotes in their neighborhoods. But as an <a href="https://naturalresources.extension.wisc.edu/uw-urban-canid-project/">interdisciplinary team</a> studying how people and coyotes interact in urban areas, we know that peaceful coexistence is possible – and that these creatures actually bring some benefits to cities. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1327368343813197824"}"></div></p>
<h2>Adaptable animals</h2>
<p>Coyotes can <a href="https://urbancoyoteresearch.com/sites/default/files/resources/Urban%20coyote%20ecology%20journal.pdf">thrive in urban environments</a> because they are incredibly adaptable. As omnivores, coyotes can <a href="https://doi.org/10.1111/j.1600-0587.2001.tb00205.x">change their diets</a> depending on <a href="https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1693&context=icwdm_usdanwrc">the type of food that’s available</a>. </p>
<p>In rural areas coyotes may feed on bird eggs, rabbits, deer and a wide range of nonanimal matter, like plants and fruits. In urban environments they’ll supplement their natural diet with human-provided food sources, such as outdoor pet feeders and garbage cans.</p>
<p>Coyotes prefer to live in packs, and usually do so in rural areas. In urban areas, coyotes live in packs as well, although it may not seem that way because they are often seen individually rather than as a group.</p>
<p>Solitary coyotes not associated with a pack are somewhat common but tend to be transitory animals looking to join a pack or establish a new one in an unoccupied territory. These solitary coyotes can roam many miles per day, which enables them to disperse to new cities in search of food. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the west side of Madison, Wisconsin, with stars indicating places a coyote stopped" src="https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477210/original/file-20220802-24-q9c9pb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Urban coyotes can roam multiple miles a day. This map of the west side of Madison, Wisconsin, tracks a male coyote collared by the UW Urban Canid Project. Each red star shows somewhere he stopped over the span of a few days.</span>
<span class="attribution"><a class="source" href="https://www.facebook.com/uwurbancanidproject/photos/a.1581580038745965/3131229720447648/?type=3">University of Wisconsin Urban Canid Project</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Some wild species need very specific types of habitat to survive. For example, the Kirtland’s warbler is a rare North American songbird that breeds only in <a href="https://www.allaboutbirds.org/guide/Kirtlands_Warbler/overview">young jack pine forests in Michigan, Wisconsin and Ontario</a>. In contrast, coyotes are <a href="https://www.worldcat.org/title/wild-canids-their-systematics-behavioral-ecology-and-evolution/oclc/1093505">habitat generalists</a> that can live on and around a wide variety of land types and covers. </p>
<p>Many kinds of habitat that <a href="https://doi.org/10.3996/062013-JFWM-040">coyotes use in rural areas</a>, such as parks, prairies, forest patches and wetlands, are also found in cities. Typically coyotes avoid the urban cores, but <a href="https://urbancoyoteresearch.com/sites/default/files/resources/Urban%20coyote%20ecology%20journal.pdf">in Chicago</a> they inhabit the downtown area and have been able to survive quite well.</p>
<p>Finally, urban coyotes have <a href="https://doi.org/10.5070/V425110351">flexible activity patterns</a>. Most urban coyotes are active mainly between dusk and dawn, when they are less visible than in daylight. However, as coyotes grow used to humans and begin to lose their fear of people, they may be seen more frequently during daylight hours.</p>
<h2>Hunting rodents and spreading seeds</h2>
<p>Studies show that urban coyotes generally avoid direct interactions with people. A long-term <a href="https://digitalcommons.lmu.edu/cate/vol4/iss1/3/">study in Chicago</a> found that these animals are good at adapting to human-built environments and navigating urban areas without being seen by humans. Often people may not realize they’re sharing the urban landscape with coyotes until they see one in their neighborhood. </p>
<p>Despite their <a href="https://www.britannica.com/topic/Coyote-mythology">trickster portrayal in folklore</a> and <a href="https://www.youtube.com/watch?v=0HQeJESRcDU">popular media</a>, coyotes tend to avoid conflict. They enter urban landscapes because they’re opportunistic. And because cities don’t have <a href="https://www.merriam-webster.com/dictionary/apex%20predator">apex predators</a> like wolves or bears, there are lots of smaller wild prey species, such as squirrels and rabbits, running around for coyotes to feed on. </p>
<p>A 2021 study conducted in Madison, Wisconsin, found that the vast majority of human interactions with coyotes there <a href="http://dx.doi.org/doi:%2010.1093/jue/juaa032">were benign</a>. When asked to rank how aggressive coyotes had been during interactions on a scale of 0 (calm) to 5 (aggressive), most of the 398 people in the study chose zero. More than half of the coyotes in the study moved away from the human, indicating that the animals maintained a healthy fear of people.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic explaining how to behave around urban coyotes" src="https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476380/original/file-20220727-11-fg0yin.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Coyotes are present throughout Florida, including in urban areas like Miami and Tampa-St. Petersburg.</span>
<span class="attribution"><a class="source" href="https://myfwc.com/media/15892/coyotes-in-florida-infographic.jpg">Florida Fish and Wildlife Conservation Commission</a></span>
</figcaption>
</figure>
<p>And having coyotes around can be useful. In urban areas they are at the top of the food chain and can help regulate populations of prey species such as rabbits, rats and mice. Since coyotes are omnivores, they also eat plant material and spread seeds when they defecate. </p>
<p>Our team is working to learn <a href="https://doi.org/10.1080/10871209.2020.1748768">how people feel</a> about coyotes in their urban communities so that we can identify the best ways to foster positive human-coyote relationships. In Madison, we’ve found that many people appreciate coyotes and are likely to respond positively to messages that highlight coyotes as a valued part of the urban landscape. </p>
<h2>Don’t be afraid to haze</h2>
<p>If you encounter an urban coyote, it’s OK to enjoy watching it from a safe distance. But then <a href="https://www.humanesociety.org/resources/coyote-hazing">haze it</a> by making noise – for example, yelling and waving your arms to look big. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JlC8KTDiIRs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">University of Wisconsin wildlife extension specialist David Drake shows how to haze a coyote.</span></figcaption>
</figure>
<p>For animal lovers, this might seem harsh, but it’s extremely important to make sure the coyote doesn’t get too close. This teaches the animal to keep away from people. In the rare cases in which urban coyotes have attacked humans, the animals typically had <a href="https://www.theguardian.com/us-news/2022/may/23/urban-coyotes-us-suburbs-dallas">become habituated to human presence</a> over time.</p>
<p>If you have pets, keep them leashed in public parks and watch them when they’re loose in unfenced yards. <a href="https://doi.org/10.3389/fevo.2021.687504">Keep their food inside as well</a>. To a coyote, a dishful of dog food is an easy free meal, and it may cause coyotes to revisit the area more frequently than they would if human-provided food weren’t accessible. </p>
<p>Based on existing research, we believe urban landscapes have plenty of room for coyotes and humans to <a href="https://naturalresources.extension.wisc.edu/uw-urban-canid-project/coexisting-with-canids/">coexist peacefully</a>. It starts with each species giving the other enough room to go about its business. To learn more about these amazingly adaptable animals, check out the national nonprofit <a href="https://projectcoyote.org/">Project Coyote</a> and the Wisconsin-based <a href="https://naturalresources.extension.wisc.edu/uw-urban-canid-project/">Urban Canid Project</a>.</p><img src="https://counter.theconversation.com/content/186893/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Drake receives funding from a variety of federal and state government agencies, as well as foundations </span></em></p><p class="fine-print"><em><span>Associate Professor, Department of Life Sciences Communication and Division of Extension, University of Wisconsin-Madison</span></em></p><p class="fine-print"><em><span>Mary Magnuson is affiliated with the University of Wisconsin Urban Canid Project. She is an AAAS Mass Media Fellow working with The Conversation for the summer of 2022. </span></em></p>Urban coyotes prey on rodents and spread plant seeds. It’s OK to observe them from a distance, but then you should chase them off.David Drake, Professor of Forest and Wildlife Ecology and Extension Wildlife Specialist, University of Wisconsin-MadisonBret Shaw, Associate Professor of Life Sciences Communication, University of Wisconsin-MadisonMary Magnuson, Master's student in Environment and Resources, University of Wisconsin-MadisonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1807922022-04-22T01:55:39Z2022-04-22T01:55:39ZHow to control invasive rats and mice at home without harming native wildlife<figure><img src="https://images.theconversation.com/files/459003/original/file-20220421-19-krrb4f.jpg?ixlib=rb-1.1.0&rect=72%2C16%2C5294%2C3573&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>As I write this article, a furry blur of a rodent has just scampered across the room and under the couch. It’s autumn in Australia and, as air temperatures plunge outside, rodents start seeking the warmth and plentiful food inside our houses.</p>
<p>This is a familiar experience for many of us, whether it’s a mouse in your house, or rats invading your chicken cage or eating the fruit from your trees. </p>
<p>In fact, a <a href="https://assets.researchsquare.com/files/rs-387256/v1/4d4927bb-e1bb-4b55-8bdc-df64dead5b3c.pdf?c=1631880789">study</a> last year found rodents have cost the global economy up to US$35.53 billion between 1930 and 2018, largely due to the damage they inflict on farms.</p>
<p>Farmers along Australia’s east coast know this all too well. The rodent problem can amplify to <a href="https://theconversation.com/no-one-ever-forgets-living-through-a-mouse-plague-the-dystopia-facing-australian-rural-communities-explained-by-an-expert-159339">plague proportions</a> following wet years and warmer than average minimum temperatures. </p>
<p>Having personally experienced a mouse plague while staying on the Nullarbor, I can attest that these are horrible experiences. The economic losses are huge and the unrelenting waves of mice day and night are horrifying for those who have to live with them, sometimes for months. </p>
<p>Last year’s plague resulted in a <a href="https://theconversation.com/mouse-plague-bromadiolone-will-obliterate-mice-but-itll-poison-eagles-snakes-and-owls-too-160995">proposal to drop the poison bromadiolone</a> over large parts of eastern Australia. Had it been successful, it would have significantly harmed non-target species of native wildlife such as owls, goannas and quolls, which our research has shown are <a href="https://theconversation.com/australias-reptiles-may-be-spreading-rat-poison-through-the-food-chain-94922">highly vulnerable to a range of rodenticides</a> as they travel up the food chain.</p>
<p>Indeed, I’m often asked by people grappling with invasive rodents how best to manage them without harming native wildlife. So, here’s some advice.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1385760654519242754"}"></div></p>
<h2>Mechanical traps</h2>
<p><em>Use them indoors only</em></p>
<p>Sometimes old-fashioned is best. The snap traps you might remember from your childhood are still a highly effective way of removing pesky rodents from your home. Just keep them away from the exploring toes of children and pets! </p>
<p>Some newer plastic traps with pivoting jaws that close on the mouse are, in my experience, less effective and can risk injuring but not killing the mouse. I’ve had several experiences of traps being dragged away by a mouse caught only by a leg. </p>
<p>A new entry to the Australian market is a type of mechanical trap, the A24. It’s self-resetting with a scent-based lure and can kill 24 mice or rats on one canister. These, however, are not suitable for use outside in areas with native wildlife. </p>
<p>I recently had an horrific experience of a native quenda (bandicoot) killed by one of these traps set on my bush property. I was devastated and, after deploying a monitoring camera on the deactivated trap, I found possums are at grave risk from this type of trap, too. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bandicoot" src="https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459015/original/file-20220421-14-suu48c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Native animals such as quenda (bandicoots) are at risk of getting caught in mechanical traps meant for invasive rodents.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>These traps don’t seem to discriminate invasive rodents from native wildlife and <a href="https://research-scotland.ac.uk/bitstream/handle/20.500.12594/53/SASA_A24_Hedgehog_Report.pdf?sequence=1">are known</a> to kill native birds, rabbits and hedgehogs in New Zealand. </p>
<p>Governments need to reconsider the ethics and conservation implications of such traps in Australia. It is my view that no mechanical traps should be set outside the home or shed where there’s risk to native wildlife. </p>
<p>The Conversation asked Goodnature, which manufactures A24 traps, whether it is taking steps to address this issue. </p>
<p>Goodnature co-founder and industrial designer Craig Bond said the traps’ threat to native animals is “ideally mitigated by the overall benefit to nature”. He said the company is working on preventative measures such as warning users, through various means, about reducing risks to native wildlife. Bond went on:</p>
<blockquote>
<p>We can and do put processes in place to mitigate and hopefully empower our trappers. And we have employed staff with the requisite expertise to do that. </p>
<p>However […] we can be more proactive in our warnings regarding the risk to non-target species. </p>
<p>The issue in the past has not been widespread but [we] understand that Australia is a particularly vulnerable environment. </p>
</blockquote>
<p>Bond said Goodnature was keen to learn more about reducing the risks its traps might pose to native Australian wildlife.</p>
<h2>Electric traps</h2>
<p><em>Effective and humane</em></p>
<p>These are battery-powered rat and mouse traps that work by delivering a fatal shock to rodents once they make contact with the two plates in the trap. </p>
<p>These are highly effective and very humane because upon touching two plates, a fatal electric shock is administered, instantly stopping the heart. </p>
<p>Though not cheap, I swear by these traps as they catch and kill quickly using a bait of your choice, such as peanut butter. There is minimal risk of impacts to non-target animals in the home. </p>
<p>But again – they definitely should not be used where native wildlife could enter the trap. The traps are usually labelled as being not for outdoor use and this advice should be followed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-one-ever-forgets-living-through-a-mouse-plague-the-dystopia-facing-australian-rural-communities-explained-by-an-expert-159339">‘No one ever forgets living through a mouse plague’: the dystopia facing Australian rural communities, explained by an expert</a>
</strong>
</em>
</p>
<hr>
<h2>Live traps</h2>
<p><em>Compassionate or inhumane?</em></p>
<p>Live catch traps are popular with those not willing to kill animals. These include <a href="https://pestkill.org/mice/bucket-trap/">bucket traps</a> for dealing with large plagues. The main issue is finding ways to dispatch them. </p>
<p>Killing the invasive rodents often requires drowning them and, if the animals are not killed, you are releasing vermin for somebody else to deal with. Unless you address the problem of how they’re entering your home, they may just be back for a visit again that night. </p>
<p>Some live traps are inhumane, such as glue traps, which comprise sticky boards to capture rodents that walk over them. These traps are not recommended under any circumstances. </p>
<p>Glue traps are not only <a href="https://gala.gre.ac.uk/id/eprint/35143/7/35143_BELMAIN_An_assessment_of_animal_welfare_impacts.pdf">cruel</a> as it can take days for the animal to die, but they do not discriminate. Unless contained and used carefully, they have a high risk of catching reptiles, birds or other non-target species.</p>
<h2>Poisoned baits</h2>
<p><em>Best for industrial and broadscale use</em></p>
<p>Despite the risk to non-target animals, baits will always be needed for large scale rodent problems, such as mouse plagues. However, they are not humane as animals die slowly by blood loss over an <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/ps.1623">average of 7.2 days</a> and have the most potential for poisoning other species.</p>
<p>In Australia, it’s almost always unnecessary to use so-called “second-generation baits” such as brodifacoum. These baits are made in response to rodents developing resistance to some chemical formulations, and require only one feed to be fatal. </p>
<p>The active ingredients in second generation baits have a very long persistence time in the liver of animals that eat them, resulting in widespread secondary poisoning along the food chain. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mouse-plague-bromadiolone-will-obliterate-mice-but-itll-poison-eagles-snakes-and-owls-too-160995">Mouse plague: bromadiolone will obliterate mice, but it'll poison eagles, snakes and owls, too</a>
</strong>
</em>
</p>
<hr>
<p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236234">Research</a> from 2020 showed invasive rodents in Australia are unlikely to have the gene for rodenticide resistance shared by their kin from Europe and North America. Consequently, some first generation products containing coumatetralyl and some natural alternatives such as zinc phosphide can be safely used in Australia to control rodents. </p>
<p>These products have a much shorter half life in the livers or rats and mice. What’s more, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969718322836">a 2018 study</a> didn’t detect them in significant quantities in dead southern boobook owls, which eat mice. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459009/original/file-20220421-13-k5l5w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Southern boobook owl.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>It’s also important to remember that baits must be deployed according to manufacturer’s instructions. Too often I hear stories of people throwing wax baits or grain baits into their gardens. </p>
<p>This is horrifying given the direct access this provides to possums, bandicoots, birds, small children and pets. Most baits should be deployed in bait holders that prevent exposure to non-target species.</p>
<h2>Pest management is holistic</h2>
<p>We should recognise that pest management is a holistic activity. Relying on any one technique is unlikely to be sufficient. </p>
<p>Rodent-proofing your house, shed or grain silos as much as possible is essential in the war against pests. This might include sealing water and power inlets, holes in skirting boards and gaps or holes in grain storage facilities. </p>
<p>On a commercial scale, investing in modern vermin-proof facilities such as sealed grain silos and blocking all possible gaps, may well balance out the long-term expense of baiting. They certainly come with a much reduced risk to native wildlife.</p><img src="https://counter.theconversation.com/content/180792/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Davis is a member of Birdlife Australia, the Ecological Society of Australia and the Society for Conservation Biology. He has no conflicts of interest to declare.</span></em></p>With temperatures plunging, rodents have started seeking the warmth and food inside our houses. Here’s how to deal with them effectively and humanely – without accidentally catching native animals.Robert Davis, Senior Lecturer in Wildlife Ecology, Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1578892021-04-01T19:03:58Z2021-04-01T19:03:58ZMeet the Egyptian spiny mouse: this menstruating rodent may help us understand human pregnancy<figure><img src="https://images.theconversation.com/files/393027/original/file-20210401-15-1bvvqo5.jpg?ixlib=rb-1.1.0&rect=94%2C4%2C2901%2C1989&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>About 8–12% of couples of reproductive age suffer from <a href="https://academic.oup.com/hropen/article/2020/3/hoaa033/5870572">infertility</a>, and roughly 15% of all pregnancies end in <a href="https://onlinelibrary.wiley.com/doi/10.1002/bdra.23014">miscarriage</a>. </p>
<p>The underlying mechanisms of human pregnancy are still poorly understood. In part, this is because pregnancy works quite differently in most mammals. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/miscarriages-affect-1-in-6-pregnancies-we-need-better-investigations-and-treatments-120672">Miscarriages affect 1 in 6 pregnancies. We need better investigations and treatments</a>
</strong>
</em>
</p>
<hr>
<p>However, recent research indicates the Egyptian spiny mouse, which menstruates like humans do, could offer an excellent model for research. Our <a href="https://www.nature.com/articles/s41598-021-84361-z">new study</a>, published in Scientific Reports, shows the lining of the mouse’s uterus, or endometrium, also grows in a human-like way to prepare for embryo implantation. </p>
<h2>Why animal models are important</h2>
<p>There are many reasons for miscarriage and other pregnancy complications, ranging from hormonal and vitamin imbalances to failure of placental development and impaired embryo implantation. To understand these conditions, researchers need to do experiments – but doing experiments on humans poses serious ethical, practical and financial challenges.</p>
<p>That’s why researchers try to “model” the conditions in suitable laboratory animals. Animal models (using rodents in particular) have helped explain many aspects of human reproduction, but they are limited by fundamental differences between human reproduction and that of other species. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-mightnt-like-it-but-there-are-ethical-reasons-to-use-animals-in-medical-research-58878">We mightn't like it, but there are ethical reasons to use animals in medical research</a>
</strong>
</em>
</p>
<hr>
<p>Less than 2% of all mammal species menstruate, with most instead having an <a href="https://en.wikipedia.org/wiki/Estrous_cycle">oestrus cycle</a> (“going on heat”). Aside from humans, most menstruating species are great apes or old-world monkeys. </p>
<p>Non-human primates like these would be the most biologically appropriate animals for modelling human reproduction. But their large size, complex welfare requirements and high costs have prevented their adoption as laboratory animals.</p>
<p>So, to study and manage human pregnancy more effectively, we need a more appropriate menstruating animal model of female reproduction. </p>
<h2>The menstruating spiny mouse</h2>
<p>The Egyptian spiny mouse (<em>Acomys cahirinus</em>) was recently shown to have human-like <a href="https://www.sciencedirect.com/science/article/abs/pii/S0002937816304768">menstruation</a>. This had never been seen before in any rodent, and the discovery gives researchers an unprecedented non-primate model for studying menstrual and gynaecological disorders. </p>
<p>Researchers from Monash University have since delved deeper into the mystery of spiny mouse reproductive biology. The researchers have provided an in-depth characterisation of the <a href="https://academic.oup.com/humrep/article/33/9/1715/5055926?login=true">menstrual cycle</a>, identified PMS-like <a href="https://academic.oup.com/humrep/article/34/2/308/5248532?login=true">behaviour</a> and, most recently, early embryo implantation and <a href="https://www.nature.com/articles/s41598-021-84361-z">pregnancy</a>.</p>
<h2>Endometrial growth</h2>
<p>In <a href="https://www.nature.com/articles/s41598-021-84361-z">our study</a> published in Scientific Reports, we discovered that the lining of the spiny mouse’s uterus displays similar patterns of growth and receptivity to embryo implantation as other menstruating species.</p>
<p>Before an embryo can implant, the uterus lining must more than double in size and begin secreting the required proteins to encourage an embryo to implant correctly. This study demonstrated simultaneous increases in thickness and receptivity of the spiny mouse endometrium before embryo implantation, closely reflecting the events in other menstruating species.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392716/original/file-20210331-13-11wue4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A fluorescent image of the spiny mouse uterus just before embryo implantation. The green chunk at the bottom left is the muscle of the uterus, and the thinner green structures are the uterine arteries. Blue shapes are cell nuclei, and the red dots within the arteries are blood cells, and red outside the arteries is either blood cells or protein.</span>
<span class="attribution"><span class="source">Jarrod McKenna</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Spiral arteries</h2>
<p>In all menstruating species, spiral-shaped arteries grow in the uterine lining. </p>
<p>These spring-like arteries are vital to provide nutrients for a growing placenta, and poorly functioning spiral arteries are associated with several pregnancy complications such as pre-eclampsia and intra-uterine growth restriction. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-pre-eclampsia-and-how-does-it-affect-mums-and-babies-97781">Explainer: what is pre-eclampsia, and how does it affect mums and babies?</a>
</strong>
</em>
</p>
<hr>
<p>In our study, we observed the growth of spiral arteries prior to embryo implantation, but also changes to their structure and function soon after. This also occurs during early pregnancy in other menstruating species including <a href="https://pubmed.ncbi.nlm.nih.gov/21705078/">gorillas</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/21459441/">chimpanzees</a> and <a href="https://www.degruyter.com/document/doi/10.1515/JPM.2006.089/html">humans</a>. </p>
<h2>Looking to the future</h2>
<p>Although our knowledge of spiny mouse reproductive biology is in its infancy, what we do know is very encouraging. </p>
<p>This study is further proof for the unique reproduction of the spiny mouse and adds to the growing list of reproductive traits we share with this fascinating species. Not only do spiny mice have human-like menstruation, but this recent study demonstrates similarities of endometrial growth, receptivity and the critical role of spiral arteries during early pregnancy of menstrual species. </p>
<p>Further research into spiny mouse reproductive biology may reveal new treatment options for pregnancy complications. In turn, this could change how we treat and monitor pregnancy and lead to better outcomes.</p><img src="https://counter.theconversation.com/content/157889/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jarrod McKenna is funded by the Australian Government Research Training Program supported by Monash University. </span></em></p>Discovering a mouse with a reproductive system surprisingly similar to our own is good news for pregnancy research.Jarrod McKenna, PhD candidate and academic tutor, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1519822020-12-16T20:08:43Z2020-12-16T20:08:43ZBaby mice ‘shut down’ to survive extreme cold on the highest mountain tops<figure><img src="https://images.theconversation.com/files/375179/original/file-20201215-21-1149vme.jpg?ixlib=rb-1.1.0&rect=26%2C8%2C5886%2C4042&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">North American deer mice pups have adapted to extreme cold conditions in an unusual way.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>It’s early 2019, and biologist Jay Storz is struggling to breathe. He has just made it to the top of Llullaillaco, a Chilean volcano about three-quarters the height of Mount Everest, in search of a rumour. </p>
<p>Up this high, the air is thin, so there isn’t much oxygen and every step is an effort. Storz’s colleague, Mario Perez Mamani, spots movement among the rocks and Storz springs into action. He makes a successful grab and sits back, smiling. In his fist is the highest-dwelling animal in the world: <a href="https://doi.org/10.1073/pnas.2005265117">A yellow-rumped leaf-eared mouse (<em>Phyllotis xanthopygus rupestris</em>)</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/bypnzuF9f4w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Biologists Jay Storz and Mario Perez Mamani capture a yellow-rumped leaf-eared mouse.</span></figcaption>
</figure>
<p>I’m a Canadian biologist who is part of an international team of scientists that includes Storz; we study mountain top mice to learn how animals adapt to extreme environments. When it comes to living the high life, small rodents and lagomorphs (relatives of rabbits) are the undisputed high-altitude champions from the Andes to the Himalayas. Our study species, the North American deer mouse (<em>Peromyscus maniculatus</em>), is found from sea level to the summit of the highest Rocky Mountains, giving it the broadest altitudinal range of any mammal on the continent.</p>
<h2>Surviving extreme environments as a pup</h2>
<p>Mountain tops are some of the most extreme environments on Earth, and many summits are freezing cold all year round. For small mice, this can be a big problem. Their surface area is large relative to their mass, so they lose heat quickly.</p>
<p>Most warm-blooded animals like birds and mammals — endotherms — use energy from food to make their own heat and prevent their body temperature from dropping too low. Mammals use muscle to shiver or a special kind of fat called brown adipose tissue that makes heat without shivering. Both shivering muscle and brown fat need energy and oxygen to make heat. </p>
<p>Oxygen is in short supply on a mountain top but high-altitude mice have found a way around this problem. Highland populations of the North American deer mouse, native to the Rocky Mountains and the White Mountains, have evolved to maximize heat production. Their <a href="https://doi.org/10.1073/pnas.1120523109">brown fat and skeletal muscle</a> are fat-burning machines, and their specialized <a href="https://doi.org/10.1098/rspb.2019.2750">cardiovascular and respiratory systems</a> deliver all the oxygen and fuel needed. Maximizing heat production means an adult mouse is more likely to <a href="https://doi.org/10.2307/2640830">survive on the cold mountain top</a>.</p>
<h2>Generating heat for survival</h2>
<p>Some mammals are born with fully functioning heat-generating mechanisms. But for many species, these systems mature after birth. In these animals — including humans and mice — brown fat matures first and takes on early heat production. </p>
<p>At sea level, a baby mouse’s brown fat takes about <a href="https://doi.org/10.1098/rspb.2019.0841">eight days to develop</a>. By that point, the babies, or pups, have tripled in size and are starting to grow fur. In another two short weeks, they will be old enough to leave home, but these first few weeks are treacherous. High predation risk and the energetic costs of growth mean less than half of baby mice born in the wild make it to adulthood. </p>
<p>But high-altitude mice have evolved a surprising strategy to help survive this early life stage: they let themselves get cold. Our research found that <a href="http://doi.org/10.1242/jeb.210963">heat-producing systems of high-altitude deer mouse pups mature slowly compared to mice from lower elevations</a>. When we looked at the genes responsible for these traits, we found that in both brown fat and skeletal muscle, <a href="https://doi.org/10.1093/molbev/msaa086">the metabolic pathways associated with heat production were turned off in high-altitude pups</a>, who had to rely on their mothers for warmth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A hand holding a very young mouse." src="https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374537/original/file-20201211-17-1h74p7w.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A 10-day-old North American deer mouse pup. At this age, a lowland pup is able to stay warm using specialized heat-producing brown fat. Pups native to high altitudes have evolved to delay the maturation of this tissue.</span>
<span class="attribution"><span class="source">(Cayleih Robertson)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Mother rodents will sit on their pups while they nurse, keeping them nice and toasty. If pups can’t produce their own heat, their body temperature will slowly drop whenever the mother is away.</p>
<h2>Tolerance for cold</h2>
<p>Humans get hypothermia if our body drops by 2 C, so this may seem dangerous. But baby mice are remarkably cold-tolerant. Their body temperature can drop almost to freezing for hours, warming up again when their mother returns.</p>
<p>Our research leads us to believe that high-altitude mice conserve their energy use for growing, rather than staying warm. The combination of cold and low oxygen means that most mammalian babies (from humans to rats) can’t grow properly at high altitude.</p>
<p>The deer mouse is able to survive to adulthood at high altitudes because of its ability to slow down metabolic activity and conserve energy. Since this is the exact opposite strategy used by adult deer mice, our work highlights how important it is to study young animals if we want to understand how a species has evolved.</p><img src="https://counter.theconversation.com/content/151982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cayleih E. Robertson receives funding from the Natural Sciences and Engineering Research Council of Canada</span></em></p>Mice pups living on mountain tops reserve their energy for growth rather than warmth. When they get too cold, they conserve energy by slowing down their metabolic processes.Cayleih E. Robertson, Postdoctoral Fellow in Comparative Physiology, McCall MacBain Teaching and Leadership Fellow, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1500422020-12-09T13:18:01Z2020-12-09T13:18:01ZBitter battles between stinkbugs and carnivorous mice could hold clues for controlling human pain<figure><img src="https://images.theconversation.com/files/373125/original/file-20201204-21-rfpuq6.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C2365%2C1408&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Small but fierce: Grasshopper mice can eat prey that are toxic to other mice. </span> <span class="attribution"><span class="source">Lauren Koenig</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>It’s hard to appreciate the value of pain when we feel it, but most living things would not survive without it. Pain is a signal that something is causing harm to your body and that you <a href="https://theconversation.com/what-is-the-best-sense-scientists-are-still-battling-it-out-113598">need to take action</a>. </p>
<p>One way to learn about pain receptors is by studying species in which these receptors seem to be absent. As an example, many animals regularly eat toxic food without suffering reactions that would cause pain in other species: <a href="https://www.wmmga.org/content.aspx?page_id=22&club_id=101643&module_id=235634">goats</a>, deer, and black bears will all happily browse on poison ivy without developing itchy rashes.</p>
<p>I have a long-standing appreciation for bizarre biology, so I wanted to learn about one of the most specialized predators in the animal kingdom: the <a href="https://www.bbc.co.uk/programmes/profiles/5zDVkCVFKMm8mG1NsjZ4WdC/grasshopper-mouse">grasshopper mouse (Onychomys torridus)</a>. These tiny rodents have a big appetite for prey that other mice prefer to leave alone because of their quarry’s chemical defenses. <a href="https://rowelab.oucreate.com/">Ashlee Rowe and Matt Rowe</a>, whose lab I worked in while they were based at Michigan State, are investigating how grasshopper mice can consume dangerous food. Understanding this ability may provide insights into pain pathways and help scientists seeking to find new, nonaddictive treatments for blocking pain signals. </p>
<h2>Mice vs. beetles</h2>
<p>To uncover more about grasshopper mouse predatory behavior, I traveled to the Sonoran Desert in southern Arizona with Olivia Guswiler, Victoria Rose, and Matt Rowe. The desert is beautiful but hostile. </p>
<p>Many animals there have developed extreme adaptations, including venoms and poisons, that help them catch food and defend themselves from predators. This makes it the perfect natural lab for studying rodents and how they’ve specialized to handle desert life.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Desert research site in Arizona" src="https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370384/original/file-20201119-23-1wjrxjy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Santa Rita Experimental Range research site in the Sonoran Desert.</span>
<span class="attribution"><span class="source">Lauren Koenig</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We focused on three related species of mice with different dietary preferences. <a href="https://en.wikipedia.org/wiki/Peromyscus">Deer mice (<em>Peromyscus</em>)</a> are omnivores, known for supplementing a diet of insects with whatever they find in kitchens all over North America. Peanut-shaped <a href="https://en.wikipedia.org/wiki/Desert_pocket_mouse">pocket mice (<em>Chaetodipus penicillatus)</em></a> prefer to eat seeds and grain, but will eat insects as a last resort. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scorpion under a blacklight" src="https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=500&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=500&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=500&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=628&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=628&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370391/original/file-20201119-15-mjkhve.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=628&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Grasshopper mice are fully capable of eating this venomous scorpion, which fluoresces under a blacklight.</span>
<span class="attribution"><span class="source">Lauren Koenig</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In contrast, southern grasshopper mice are voracious carnivores. At sunset they let out long cries, like muted teakettles, that have been described as “<a href="https://ageconsearch.umn.edu/record/157954/files/tb145.pdf">wolf howls in miniature</a>.” Their stubby legs and tan-and-white patterned coats make them look like tiny corgis, but belie their aggressive nature. Grasshopper mice attack and eat anything that moves, including centipedes, tarantulas, scorpions and even other mice. They have an astounding <a href="http://dx.doi.org/10.1126/science.1236451">immunity to scorpion venom</a>, which kills deer mice in minutes.</p>
<p>We wanted to see how grasshopper mice, deer mice and pocket mice ate different types of insects, so we trapped over 80 of them and tested their feeding behavior. We gave each mouse a cricket, which is largely defenseless, and a stink beetle (<a href="https://en.wikipedia.org/wiki/Pinacate_beetle"><em>Eleodes longicollis</em></a>). These bugs are like the chocolate-covered pretzels of the desert – high-calorie treats that contain contrasting tastes. </p>
<p>But to get to the juicy center, a predator must overcome a hard outer shell and a burning, acrid spray that the beetle squirts from its rear end. The spray contains <a href="https://en.wikipedia.org/wiki/1,4-Benzoquinone">benzoquinone chemicals</a>, which release fumes similar to bleach and can damage the eyes, nose, mouth and skin with prolonged exposure. I can personally attest to its bitter, stinging taste and the brown stains it leaves on clothes and skin.</p>
<h2>Taste tests</h2>
<p>In a typical battle, most grasshopper mice immediately attacked the beetle but were repulsed by a face full of chemical spray. Eyes closed, they would turn to rub their head in the sand, seemingly trying to brush the spray off their fur. But then, remarkably, each mouse returned to bite the beetle’s head until it was subdued. Crunching followed as the mouse held the beetle like a sandwich, working its way down the body until all that remained were six legs and an empty shell.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/cR1s7U-of68?wmode=transparent&start=4" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The battle between grasshopper mice and desert stink beetles.</span></figcaption>
</figure>
<p>The other contenders were total wimps. Deer mice sniffed around the beetles like a restaurant customer contemplating whether to order spicy chili. They all eventually gave up, although many ate the milder crickets. Some curious pocket mice inspected the insects, but remained vegetarian.</p>
<h2>Carnivorous rodents as pharmaceutical models</h2>
<p>Grasshopper mice have special skills that make them extremely efficient predators. We saw them deploy attack behaviors designed to quickly incapacitate a beetle by biting it on the head rather than the abdomen. We also saw them exhibit defense behaviors, like rubbing their face or trying to bury the beetle in the sand, suggesting that the mice likely contracted benzoquinones in their eyes, noses and mouths. Yet they relentlessly pursued the beetles in spite of this superficial discomfort. As the Rowes have suggested, this behavior may hint at some underlying form of chemical tolerance. </p>
<p>Since deer mice did not show these behaviors, they may not have the necessary adaptations for eating the same type of food. It is possible that grasshopper mice have sensory receptors that are less sensitive to benzoquinone. To address this question, the Rowe lab is currently investigating sensory receptors in deer mice and grasshopper mice.</p>
<p>But we do know that these animals show <a href="http://dx.doi.org/10.1126/science.1236451">reduced sensitivity</a> to other chemicals that trigger pain sensation. There’s even some evidence that they <a href="https://doi.org/10.1111/j.1439-0310.1981.tb01290.x">don’t show aversive conditioning to stink beetles</a>, meaning that grasshopper mice never learn to associate beetles with pain, even after they have a negative experience with the spray. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&rect=33%2C0%2C3190%2C2254&q=45&auto=format&w=1000&fit=clip"><img alt="A Grasshopper mouse eats a stink beetle headfirst." src="https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&rect=33%2C0%2C3190%2C2254&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370383/original/file-20201119-22-1jvt51q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A victorious grasshopper mouse eats a stink beetle headfirst.</span>
<span class="attribution"><span class="source">Lauren Koenig</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Future research may find even more clues in the grasshopper mouse brain about how pain sensations can be blocked. Human medications like Advil and other nonsteroidal anti-inflammatory drugs reduce pain by <a href="https://www.webmd.com/arthritis/features/pain-relief-how-nsaids-work">blocking production of certain chemicals in the body that inflame tissues</a>. Similarly, drugs that mimic keys intended to fit the shape of sensory receptor locks might stop those receptors from sending pain signals. By <a href="https://www.scienceinschool.org/2014/issue28/natural_products">copying natural examples of pain resistance</a>, scientists can design treatments to alleviate pain or identify which part of the pain pathway might be malfunctioning in chronic pain patients.</p>
<p>[<em>Understand new developments in science, health and technology, each week.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-understand">Subscribe to The Conversation’s science newsletter</a>.]</p>
<h2>You are what you eat</h2>
<p>Learning more about pain and taste receptors in grasshopper mice may also help us understand how they became so different from other mice in the first place. Many carnivores have <a href="https://doi.org/10.1073/pnas.1118360109">fewer taste receptors than herbivores</a>, possibly because they don’t need to detect which plants are toxic. Marine mammals that swallow their food whole, like sea lions and dolphins, lack most taste receptors altogether. </p>
<p>Other animals, like <a href="https://doi.org/10.1006/anbe.2003.2059">vampire bats</a>, seem incapable of conditioned taste aversion – the tendency to avoid a food that has made you feel sick in the past. Such behavior would be useless for animals that follow a strict diet of mammalian blood and rarely encounter toxic food.</p>
<p>Perhaps genetic changes in the grasshopper mouse taste receptors helped them <a href="https://doi.org/10.1037/0735-7036.108.4.394">to outcompete other rodents</a> for limited food in the desert. By eating insects and arachnids that no one else can handle, grasshopper mice occupy a unique dietary niche that helps them survive in one of the harshest environments on Earth.</p>
<p>Considering that humans and mice are so genetically similar, these ferocious carnivores may someday be a leading prototype for designing drugs that relieve human suffering.</p>
<p><em>Editors note: This story has been updated to better reflect the contributions of Ashlee and Matt Rowe.</em></p><img src="https://counter.theconversation.com/content/150042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lauren Koenig receives funding from the National Science Foundation. </span></em></p>Animals that regularly dine on toxic food may hold clues for designing new drugs to treat persistent pain in humans.Lauren Koenig, PhD Candidate in Integrative Biology, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1469242020-11-10T04:43:14Z2020-11-10T04:43:14ZShy rodents may be better at surviving eradications, but do they pass those traits to their offspring?<figure><img src="https://images.theconversation.com/files/368459/original/file-20201110-23-axcb4l.jpg?ixlib=rb-1.1.0&rect=0%2C14%2C3304%2C2181&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Rodents such as house mice (<em>Mus musculus</em>) aren’t just pests at home, they can cause serious damage to native ecosystems.</p>
<p>Lord Howe Island, for example, harboured <a href="https://www.abc.net.au/news/2019-06-11/rat-infestation-on-lord-howe-island-splits-residents/11180624?nw=0">up to</a> 150,000 introduced rats and 210,000 introduced mice that wrought havoc on the island’s native wildlife, before an intensive eradication effort was carried out. It was declared a <a href="https://www.australiangeographic.com.au/news/2020/01/win-for-endangered-lord-howe-island-woodhens/">success</a> earlier this year, although monitoring for survivors will continue. </p>
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Read more:
<a href="https://theconversation.com/invasive-predators-are-eating-the-worlds-animals-to-extinction-and-the-worst-is-close-to-home-64741">Invasive predators are eating the world's animals to extinction – and the worst is close to home</a>
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<p>But emerging research suggests the success of eradicating pests may depend on the personality of individual animals within a species. </p>
<p>Bolder, more active, aggressive or social individuals are more likely to interact with baits, traps or <a href="https://academic.oup.com/beheco/article/28/6/1504/4210926">new objects and foods</a>. As a result, they can be <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.0030-1299.2008.16567.x?casa_token=azpKp0d5V6QAAAAA%3ABQVuqWz3O2z3mdRDdF1Wnywx_lYNwjVQ5HgIhSzbYBqUFm_EiNnwbGJbSIMh0FRxafMbP6RpVZRP1DazTg">removed quickly</a>.</p>
<p>On the other hand, shyer or less active individuals <a href="https://www.sciencedirect.com/science/article/pii/S000334721200053X?casa_token=c-6mOegvXv4AAAAA:VxYGj3pXIzKPCzbSkB_WhJ_6rSTfMGgZybqSiZoy6nlwGqkSJQ4nX0QrdlFlkNUUVBwYAHKyAfg">can take longer</a> to be caught.</p>
<p>Why is this so important? Well for starters, animals that actively avoid eradication will breed and repopulate. </p>
<p>If the personality traits of these survivors are reflected in all, or even most, offspring then we could be facing a pest population that is incredibly difficult to remove. This is what <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/eap.2247?casa_token=6xKgF7qKsEoAAAAA:3PuCTo5UHy2NxYISJb1MvG1OexcF33cByxDc4mHGpO1DrJQeaR_jio9M5u-kAov5vf_Vik6Kei5ec2EpHg">our new research</a> aimed to find out. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial view of Lord Howe Island" src="https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368474/original/file-20201110-20-10g4b5n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Islands, such as Lord Howe Island off NSW, are refuges for a range of wildlife often not found anywhere else in the world.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>When eradication efforts fail</h2>
<p>Australia is home to more than <a href="https://invasives.org.au/our-work/islands/">8,300 islands</a> that provide refuge for unique species often found nowhere else in the world, including species now extinct on the mainland. </p>
<p>Introduced mammalian pests, particularly rodents, are huge threats to island species, which often evolve without predators. They don’t recognise these introduced mammals as a threat, making them easy targets. </p>
<p>For example, <a href="https://www.cambridge.org/core/journals/antarctic-science/article/evidence-of-mouse-attacks-on-albatross-chicks-on-subantarctic-marion-island/FA02807B3011973762C0BFE418CB3B17">a 2010 study</a> observed house mice literally eating albatross chicks alive on Marion Island near Antarctica. Neither the chicks nor parents showed any defensive or escape behaviour. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/feral-animals-are-running-amok-on-australias-islands-heres-how-to-stop-them-64307">Feral animals are running amok on Australia's islands – here's how to stop them</a>
</strong>
</em>
</p>
<hr>
<p>Eradicating introduced pest species is the ultimate solution if we want to protect native island ecosystems.</p>
<p>But eradication efforts are only effective if every animal in a population is eliminated. While most failed efforts likely go unreported, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12190">on average</a>, 11% of eradication attempts for rodents fail. For house mice in particular, failure rates can be as high as 75%. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Nesting albatross on Marion Island" src="https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368472/original/file-20201110-21-yjd8cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nesting albatross on Marion Island, where chicks were found to be eaten by introduced house mice.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>When efforts fail, pest populations quickly bounce back. <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsos.160110">One study</a> in 2016 found around 50 rats survived an eradication attempt by avoiding baits on Henderson Island in the South Pacific. Within only two years, the population had exploded into roughly 75,000 animals. </p>
<h2>Developing personality traits</h2>
<p>So if animal behaviour influences if an individual enters a trap or takes a bait, how much of the parent personality is reflected in the offspring? </p>
<p>If you’ve thought about the similarity between parents and children — in both human and our animal companions — then you know some offspring behave just like their parents, while others are very different. </p>
<p>Personality traits develop through a combination of <a href="https://academic.oup.com/beheco/article/28/3/732/3007699">experience</a>, <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rsbl.2013.0120">learning from parents</a> and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-185X.2007.00010.x?casa_token=ZpAGu_8jKd8AAAAA:viBLwqpK3Q1uHxxlbsPi3SHIzsAbH-Yn57NLbPwWAMV8uu7SwVFykF3BFY_Jiv3HPvHNjVPA8VKE9pHrVA">genetic inheritance</a>. </p>
<p>Humans have selectively bred domestic animals, including <a href="https://www.sciencedirect.com/science/article/pii/S0168159102001211?casa_token=CuqvJSUKeAUAAAAA:aJD_expxE9bjpdOxWCacZnYlvoAKYrQHDxFytlE0NwJKHyIiaykzymbXRamIegzC5ebEzgObA8g">dogs</a>, <a href="https://academic.oup.com/jas/article-abstract/73/8/2249/4632873">cattle</a> and <a href="https://psycnet.apa.org/doiLanding?doi=10.1037%2F0735-7036.118.4.434">horses</a> for preferred personality traits, such as docility. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/understanding-dog-personalities-can-help-prevent-attacks-120224">Understanding dog personalities can help prevent attacks</a>
</strong>
</em>
</p>
<hr>
<p>And studies on laboratory animals, including <a href="https://www.sciencedirect.com/science/article/pii/S0376635705002330?casa_token=gTgO7AuXJasAAAAA:Lj3ROxHhC0C5K6FxIuFB4yqqE-76mwlTlgQwkTEws4bdqLwTXSflixFPyw5hrFe6JxF2htwpfIM">mice</a> and <a href="https://link.springer.com/article/10.1007/BF01065624">chicks</a>, have found selecting for preferred traits in parents can lead to these traits being strongly expressed in the offspring within a single generation. </p>
<p>However, can this immediate generational response occur in wild populations?</p>
<h2>What our study did</h2>
<p>To begin untangling this web, we used house mice as a model species and mimicked a failed eradication, where residual mice (the would-be survivors) were selected for biased personality traits. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1341&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1341&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368463/original/file-20201110-13-z8qmre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1341&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A mouse in our study caught in a trap.</span>
<span class="attribution"><span class="source">Kyla Johstone</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>After catching wild house mice, we tested for personality traits by filming their behaviour in a modified open-field arena. Mice that moved frequently between compartments and into light compartments (which present a risky scenario to a small nocturnal rodent) were considered to be “high active-bold” individuals. </p>
<p>Based on their behaviour, we then grouped individual mice into populations: high active-bold individuals, low active-bold (shy) individuals and intermediate individuals. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-know-if-were-winning-the-war-on-australias-fire-ant-invasion-and-what-to-do-if-we-arent-121367">How to know if we’re winning the war on Australia’s fire ant invasion, and what to do if we aren't</a>
</strong>
</em>
</p>
<hr>
<p>To closely mimic wild conditions, we released the populations into large outdoor yards and left the mice to breed for one generation. After recapturing every single mouse from the yards, we tested the offspring for the same personality traits.</p>
<h2>The good news</h2>
<p>Interestingly, although the parent populations had strong personality biases, there was a broad spectrum of personality among offspring of every population. In other words, bold mice didn’t necessarily produce bold offspring, nor shy mice, shy offspring.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A juvenile mouse" src="https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1066&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1066&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1066&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368467/original/file-20201110-15-14yteev.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A juvenile mouse from our study. Mice born from shy parents didn’t necessarily have shy personalities.</span>
<span class="attribution"><span class="source">Kyla Johnstone</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This was reassuring news. However, demonstrating there’s no generational bias in house mice doesn’t mean it can’t arise elsewhere or in other species. And our study is an important stepping stone to explore this concept in other invasive species and over multiple generations. </p>
<p>Still, for house mouse eradications at least, our findings suggest that, even if all surviving individuals had a similar personality, by the next generation a broad spectrum of personality should emerge again. </p>
<p>This suggests we’re unlikely to be faced with a population that’s impossible to remove, and can focus on improving success rates for these difficult-to-remove individuals and species.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/compassionate-conservation-just-because-we-love-invasive-animals-doesnt-mean-we-should-protect-them-144945">'Compassionate conservation': just because we love invasive animals, doesn't mean we should protect them</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/146924/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyla Johnstone received funding from The Holsworth Wildlife Research Endowment and the Paddy Pallin Foundation. </span></em></p><p class="fine-print"><em><span>Peter Banks receives funding from the Australian Research Council, Northern Beaches Council and Landcare Research, and is a council member of the Royal Zoological Society of New South Wales</span></em></p><p class="fine-print"><em><span>Clare McArthur does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If all, or even most, offspring of the survivors are shy, we could be facing an introduced pest population that is incredibly difficult to remove.Kyla Johnstone, PhD candidate, University of SydneyClare McArthur, Professor, University of SydneyPeter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1399062020-07-12T20:01:42Z2020-07-12T20:01:42Z‘Death by irony’: The mystery of the mouse that died of smoke inhalation, but went nowhere near a fire<figure><img src="https://images.theconversation.com/files/344413/original/file-20200629-104494-bs7tcm.jpeg?ixlib=rb-1.1.0&rect=3%2C0%2C2531%2C1687&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Source: Museums Victoria/David Paul</span></span></figcaption></figure><p><em>This article is part of Flora, Fauna, Fire, a special project by The Conversation that tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Explore the project <a href="https://bushfires2020.netlify.app/">here</a> and read more articles <a href="https://theconversation.com/au/search?utf8=%E2%9C%93&q=%23bushfire+recovery+2020&sort=relevancy&language=en&date=all&date_from=&date_to=">here</a>.</em></p>
<hr>
<p>I looked through the microscope at the insides of a dead smoky mouse, and could barely believe my eyes. Thousands of tiny smoke particles lined its lungs. But the mouse had been kept more than 50 kilometres from the nearest bushfires. How could this be? </p>
<p>As it turned out, the critically endangered mouse had died from <a href="https://www.abc.net.au/news/2020-02-27/smoky-mice-die-from-bushfire-smoke-inhalation/12005790">smoke inhalation</a>. Some 45 had been held at a captive breeding facility near Canberra. Nine ultimately died - the first recorded wildlife in the world killed by bushfire smoke far outside a fire zone.</p>
<p>The deaths were a blow for conservation efforts. But in recent weeks, there’s been good news: smoky mice have been spotted at seven sites burnt in the fires. For now, at least, the species lives on.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344389/original/file-20200628-104499-1ys63ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The smoky mouse case shows bushfire smoke can affect wildlife far from the fire zone.</span>
<span class="attribution"><span class="source">NASA Earth Observatory</span></span>
</figcaption>
</figure>
<h2>A unique, bulgy-eyed rodent</h2>
<p>The smoky mouse is <a href="https://www.environment.act.gov.au/__data/assets/pdf_file/0010/576487/The_Smoky_Mouse_factsheet.pdf">shy</a>, <a href="https://www.zoo.org.au/fighting-extinction/local-threatened-species/smoky-mouse/">gentle</a> and small – usually about nine centimetres in body length, plus its tail. They are <a href="https://collections.museumsvictoria.com.au/specimens/2367974">rather cute</a>, with bulgy eyes and very soft grey fur which inspired the species’ name.</p>
<p>In the wild, the smoky mouse is limited to a few sites in Victoria’s Grampians and East Gippsland, as well as in Kosciuszko National Park in New South Wales. It lives in underground communal nests, in heath and forest habitats.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-the-bushfires-we-helped-choose-the-animals-and-plants-in-most-need-heres-how-we-did-it-138736">After the bushfires, we helped choose the animals and plants in most need. Here's how we did it</a>
</strong>
</em>
</p>
<hr>
<p>Ancestors of the smoky mouse arrived in Australia <a href="https://www.sciencedirect.com/science/article/pii/S1055790308000043?via%3Dihub">more than five million years ago</a> when the Australian continent finally drifted close enough to Southeast Asia for rodents to raft across.</p>
<p>These ancient rodents diversified into more than 50 species. Many, like the smoky mouse, <a href="https://www.environment.gov.au/system/files/resources/31499c6a-d455-4488-93eb-effe012550ff/files/pseudomys-fumeus.pdf">are in decline</a>. Others, like the <a href="https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=20199">white-footed rabbit-rat</a> have already <a href="https://www.sciencedirect.com/science/article/pii/000632079600002X">become extinct</a>.</p>
<p>Several threats are reducing smoky mouse numbers, but feral cats and foxes are a <a href="https://theconversation.com/invasive-species-are-australias-number-one-extinction-threat-116809">major cause</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=656&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=656&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=656&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=825&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=825&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344387/original/file-20200628-104522-18euf6w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=825&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Baby smoky mice photographed in 2017 at the captive breeding facility.</span>
<span class="attribution"><span class="source">Office of Environment and Heritage</span></span>
</figcaption>
</figure>
<h2>Death by irony?</h2>
<p>Some <a href="http://www.environment.gov.au/biodiversity/bushfire-recovery/priority-animals">119 animal species</a> were identified for urgent conservation intervention following the fires. The smoky mouse was among them. Modelling showed 26% of its distribution overlapped with burnt areas, and in NSW <a href="https://www.environment.nsw.gov.au/news/endangered-kosciuszko-mouse-survives-fires">more than 90% of the species’ habitat burned</a>.</p>
<p>I am a wildlife health and pathology expert based in Wagga Wagga in NSW, and part of my job is to diagnose why animals have died. The first dead smoky mouse I encountered had come from a Canberra breeding facility. It was sent by a vet and arrived via courier in mid-January. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=942&fit=crop&dpr=1 754w, https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=942&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/343117/original/file-20200622-75479-8ydlu3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=942&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Through the microscope: smoke particles in the lungs of a smoky mouse suffering smoke inhalation.</span>
</figcaption>
</figure>
<p>In a note attached, the vet suggested bushfire smoke had killed the smoky mouse – and asked, in a nod to the species’ name, if this was a case of “death by irony”. </p>
<p>Canberra, like many other cities and towns, was <a href="https://www.sbs.com.au/news/canberra-s-air-quality-is-the-worst-in-the-world-as-bushfire-smoke-shrouds-capital">shrouded in thick smoke</a> in January. But the <a href="https://www.edenmagnet.com.au/story/5088469/playing-cupid-with-mice/">breeding facility</a> was more than 50 kilometres from the nearest fire zone, so I thought the vet’s theory was unlikely.</p>
<p>When I and other veterinary pathologists examined organs of the mouse under the microscope, the only abnormality we could find was fluid and congestion in the mouse’s lungs.</p>
<p>Over the following month, eight more smoky mice died. I inspected the lungs of one – to my shock, it contained thousands of brown smoke particles. Once I knew the distribution of particles to look for, I found them in most of the other dead mice too. </p>
<p>The mice didn’t die immediately after inhaling the smoke. They hung on, but when temperatures in Canberra spiked at more than 40°C, they went into respiratory distress and died.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-season-in-hell-bushfires-push-at-least-20-threatened-species-closer-to-extinction-129533">A season in hell: bushfires push at least 20 threatened species closer to extinction</a>
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</em>
</p>
<hr>
<p>Death from smoke inhalation has long been suspected in wildlife. But it’s poorly recorded because after bushfires, the bodies of dead animals are usually incinerated or too decomposed to make a diagnosis. </p>
<p>The smoky mouse case shows bushfire smoke can damage wild animals far beyond fire zones. That means the impact of bushfires on wildlife may be greater than we thought.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=767&fit=crop&dpr=1 600w, https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=767&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=767&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=964&fit=crop&dpr=1 754w, https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=964&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/343115/original/file-20200622-75487-1b7ftjn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=964&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Seven smoky mice have been spotted in the wild since the bushfires.</span>
<span class="attribution"><span class="source">Museums Victoria</span></span>
</figcaption>
</figure>
<h2>A bit of good news</h2>
<p>There is hope for the smoky mouse. Motion-sensing cameras set up in Kosciuszko National Park after the fires have <a href="https://mattkean.com.au/news/media-release/endangered-kosciuszko-mouse-survives-fires">recorded smoky mice</a> at seven burnt sites. Over the next year, more sites will be surveyed to better understand how many individuals remain, and where they live.</p>
<p>Most smoky mice at the Canberra captive breeding facility survived, and there are plans to release some into the wild. This captive breeding program has also been <a href="https://minister.awe.gov.au/ley/media-releases/5-million-funding-boost-for-bushfire-affected-wildlife-in-nsw">identified as a priority for federal funding</a>.</p>
<p>But as global warming escalates, fires in Australia are predicted to become <a href="https://theconversation.com/some-say-weve-seen-bushfires-worse-than-this-before-but-theyre-ignoring-a-few-key-facts-129391">even worse</a>. Now more than ever, the future of the smoky mouse, along with many other Australian animals, hinges on decisive climate action. Captive breeding programs and blind hope will not be enough.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/conservation-scientists-are-grieving-after-the-bushfires-but-we-must-not-give-up-130195">Conservation scientists are grieving after the bushfires -- but we must not give up</a>
</strong>
</em>
</p>
<hr>
<p><a href="https://bushfires2020.netlify.app"><img src="https://cdn.theconversation.com/static_files/files/1103/Explore.gif?1594552012" width="100%"></a></p><img src="https://counter.theconversation.com/content/139906/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Peters is deputy chair of Wildlife Health Australia.</span></em></p>One vet suggested bushfire smoke had killed the smoky mouse – and asked, in a nod to the species’ name, if this was a case of “death by irony”.Andrew Peters, Associate Professor of Wildlife Health and Pathology, Charles Sturt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1292322020-02-25T13:54:03Z2020-02-25T13:54:03ZBetter rat control in cities starts by changing human behavior<figure><img src="https://images.theconversation.com/files/316723/original/file-20200223-92526-14kqpia.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4827%2C2825&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Garbage in New York's subway system offers easy meals for rats.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Subway-Trash/914563095d4744d7ae3311b35ba3248f/2/0">AP Photo/Bebeto Matthews</a></span></figcaption></figure><p>For centuries, rats have thrived in cities because of human behavior. In response, humans have blamed the rats and developed techniques for poisoning them. </p>
<p>We research urban rat populations and recognize that rats spread disease. But they are fascinating creatures that think, feel and show a high level of intelligence. Public concerns about rat poison harming wildlife are growing – a trend that we believe could eventually lead to <a href="https://smmirror.com/2020/01/santa-monica-mountains-may-soon-be-rat-poison-free/">rodenticide bans</a> in many parts of the world. Without poison as an option, humans will need other rat control methods.</p>
<p>Rats’ many negative traits are well known. They are among the most detrimental invasive animals in cities. Urban rats are like <a href="https://getpocket.com/explore/item/the-case-for-leaving-city-rats-alone">disease sponges</a>, congregating in the foulest reaches, where they pick up harmful pathogens. They carry the antibiotic-resistent MRSA (methicillin-resistant <em>Staphylococcus pseudintermedius</em>). Inside the rat gut, MRSA can interact with other diseases like ingredients in a mixing bowl, creating newer bugs that can be transported <a href="https://video.nationalgeographic.com/video/news/0000014f-0e8c-deef-a9ef-2eae5d8c0000">from septic systems into homes</a>. </p>
<p>But common approaches to managing rats often fail to address the most important factor contributing to infestations: humans and the prolific quantities of food that they waste. The more research we do on rats in <a href="https://doi.org/10.1093/jue/juz009">New York City</a> and <a href="https://doi.org/10.1098/rspb.2016.1762">worldwide</a>, the more we realize that rat behaviors contribute less to infestations than do humans. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EPrsYTiRjXk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Piles of trash near large homeless camps in Los Angeles encourage rats and the diseases they carry.</span></figcaption>
</figure>
<h2>Concerns about rat poison</h2>
<p>On Jan. 4, 2020, <a href="https://smmirror.com/2020/01/santa-monica-mountains-may-soon-be-rat-poison-free/">Malibu, California</a> banned rodenticides due to their harmful effects on nontarget wildlife, such as mountain lions. This came after the California Assembly passed a bill to <a href="https://califesciences.org/rat-poison-ban-trapped-state-senate-2019/">ban rodenticides statewide</a>; the measure died in the State Senate, but could reappear this year.</p>
<p>If curbs on use of rat poison start to spread, communities will need other ways to manage infestations. Rats cost the world’s economy <a href="http://dx.doi.org/10.5038/2164-0866.1.1.2">billions of dollars yearly</a>, mostly from contaminating food in warehouses, restaurants and home kitchens. The costs of illnesses vectored by rats are unknown because medical providers treat many sicknesses without knowing what caused them. As human populations become increasingly clustered in cities, these effects could increase. </p>
<p>Meanwhile, climate change is <a href="https://www.carbonbrief.org/powerful-evidence-global-warmings-effect-seasons-found-troposphere">shortening winter seasons</a> that limit rat reproduction. Globalization, climate change and inability to use rodenticides could result in a “perfect storm” of vulnerability to rodents on a scale humans have not experienced since the Middle Ages. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1181994915120570368"}"></div></p>
<h2>A food-focused approach</h2>
<p>Research shows that to address this problem effectively, people must start by <a href="http://www.suaire.sua.ac.tz:8080/xmlui/handle/123456789/1138">understanding the ecology of wild rodents</a>. Rats adapt to human food sources and reproduce at remarkable rates. If enough food is present, a single Norway rat (<em>Rattus norvegicus</em>) can give birth to up to 12 pups in a litter. And each well-fed pup could give birth to 12 pups of its own in as few as six weeks. </p>
<p>We believe the key to controlling rats is appreciating a key point: Because rats have short life spans of one to two years and reproduce often, they adapt quickly to changing environments. In our view, until people change their behavior, they may fail at controlling rat numbers. </p>
<p>Current mechanisms for rat control are more reactive than proactive. Urban hygiene has become big business for exterminators, but does little to control rat populations. </p>
<p>A typical approach is to take action once <a href="https://www.nytimes.com/2019/05/22/nyregion/rat-infestation-nyc.html">rodent populations are high enough</a> that their presence cannot be ignored. But rats are mostly nocturnal, small and elusive, so they typically are noticed only after their numbers are already high. </p>
<p>This reactive approach makes any control measures – excluding rats from buildings and feeding sites, setting poison baits, <a href="https://www.atlasobscura.com/articles/rats-and-cats">introducing predators</a>, asphyxiating them with <a href="https://www.popularmechanics.com/science/animals/a19842321/dry-ice-is-a-citys-newest-weapon-against-rats/">dry ice</a> (frozen carbon dioxide) or treating them with <a href="http://dx.doi.org/10.4014/jmb.1901.01067">immuno-contraceptives</a> – comparable to putting a bandage on a cancer. </p>
<h2>Changing deeply ingrained urban habits</h2>
<p>In our lab, we study the scents that rats prefer. As nocturnal animals, rats have poor vision and rely on olfaction to identify potential mates, habitats and food sources. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=844&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=844&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=844&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1060&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1060&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315548/original/file-20200214-11011-1mbcjel.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1060&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Molly, a rat in the authors’ study, wearing a GPS tag. Determining what scents rats are attracted to could aid the development of rat control tools.</span>
<span class="attribution"><span class="source">Michael Parsons</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Rats’ dietary habits are predictable. In Brooklyn, New York, they eat pizza, bagels and beer. In Paris they consume croissants, butter and cheese. Whatever local tastes people prefer, rats eat. Interrupt the continuous food supply and the rat population will drop. </p>
<p>Many city dwellers eat when they are busy, stuck in traffic or otherwise on the run. They drop wastes, such as grease-soaked napkins and hot dog buns, onto streets, playgrounds and subway tracks. Even highly conscientious people may hastily toss uneaten food and wrappers onto the top of an overflowing rubbish bin when they are stressed for time.</p>
<p>People who are working and caring for families do not take time to think about what unseen rats are doing. But our research convinces us that society can learn to stop feeding rats inadvertently. Pest management professionals, academics, policymakers and citizens can all help advance this goal, because people can radically change the ways in which they handle and dispose of food. </p>
<h2>Hire people to secure garbage</h2>
<p>We believe that giving people incentives to create sanitary environments is an effective and socially progressive strategy. Here is one example: Because so much of the rat problem in New York City is driven by curbside garbage sitting outdoors overnight, we suggest hiring unemployed or homeless individuals as evening sentinels. They would move garbage bags from the curbside into guarded common areas and then return them to the curb for early morning collections. </p>
<p>Some cities could establish citizen rat patrols that would <a href="https://patch.com/new-york/west-village/west-village-rat-academy-scheduled-prevent-pesky-rodents">train residents</a> to identify and notify property owners when they detect that rats are present. The typical indicators are barely noticeable openings appearing around buildings, or dark <a href="https://www.youtube.com/watch?v=QQZYrWodt6k">grease stains</a> on sidewalks, parks or undeveloped lots. This approach eliminates the social stigma often associated with rats by showing people how to take proactive steps before an infestation develops. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xC1bWLfCeyk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Neuroscientist Kelly Lambert taught rats to drive miniature cars in order to study neuroplasticity and learning skills.</span></figcaption>
</figure>
<p>Rats cause very expensive problems, but they also are <a href="http://dx.doi.org/10.1126/science.aal0366">surprisingly engaging animals</a> that exhibit <a href="https://doi.org/10.1016/j.bbr.2007.02.015">human-like qualities</a>, such as remorse and <a href="http://dx.doi.org/10.1126/science.1210789">empathy</a>. Scientists have trained them to <a href="https://www.newscientist.com/article/2220721-scientists-have-trained-rats-to-drive-tiny-cars-to-collect-food/">drive tiny cars</a>. As evidence that rats are thinking, feeling beings accumulates, we expect that it could make many communities more reluctant to poison them.</p>
<p>In our view, since rats are deeply rooted in human society, people need to understand how their own actions encourage rat behavior. We want to encourage brainstorming about this issue and help identify the most promising ways to manage urban rat problems effectively and humanely. </p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/129232/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Climate change, globalization and concerns about rat poison soon could drive rat infestations to levels not seen in centuries. One way to curb them is getting humans to stop wasting food.Michael H. Parsons, Visiting Research Scholar, Fordham UniversityJason Munshi-South, Associate Professor of Biological Sciences, Fordham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1140402019-03-22T13:54:47Z2019-03-22T13:54:47ZHere’s what that house proud mouse was doing – plus five other animals who take cleaning seriously<figure><img src="https://images.theconversation.com/files/265294/original/file-20190322-36283-1me4pb6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3772%2C3342&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/house-mouse-standing-on-rear-feet-137911070">Szasz-Fabian Jozsef/Shutterstock</a></span></figcaption></figure><p>A house proud mouse, considerately tidying up the workbench of the shed in which it lives, has been captured on video and shared online. The mouse pops out of a box, picks up some screws, nail clippers and a metal chain and carries them back into the box. It’s tempting to think the mouse is cleaning up its home in the same way that a human would. Of course, in biology, things are rarely that simple. </p>
<p>Cleaning a living area for hygienic reasons isn’t unusual in animals. <a href="https://www.newscientist.com/article/mg23731604-900-smell-of-death-tells-undertaker-bees-its-time-to-remove-corpses/">Bees will remove corpses from the hive</a>, <a href="http://sciencenetlinks.com/science-news/science-updates/fatherly-fish/">male fish will pick bits of mould and silt</a> from their eggs. <a href="https://insider.si.edu/2017/09/clean-sexy-panamas-golden-collared-manakins/">Clearing debris from a display area is common in birds</a> that dance to attract a mate. None of these apply to the mouse, so we need to look for an explanation that is based in the innate behaviours of rodents.</p>
<p><a href="https://www.terminix.com/pest-control/rats/pack-rat/">Packrats</a> in North America have a habit of collecting shiny objects, stones and wood to protect their nests. Some mice like to keep a good larder – when food is plentiful, <a href="https://scholar.google.co.uk/scholar?as_ylo=2015&q=hoarding+in+rodents&hl=en&as_sdt=1,5">they will hoard it</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1108021056650936320"}"></div></p>
<p>Many rodents <a href="https://www.sciencedirect.com/science/article/pii/S0166432897001629">bury novel objects</a> that they find in their territory and this is sometimes thought to be an <a href="https://link.springer.com/article/10.1007/s00213-009-1466-y">extension of the natural digging response</a> that all rodents have. Mice and rats are keen tunnellers so the urge to dig is an important part of their behavioural repertoire. </p>
<p>Mice also <a href="https://journals.sagepub.com/doi/pdf/10.1258/002367796780684890">manipulate their bedding</a> to make a nest. Though it’s difficult to be sure with only a short video as evidence, it’s possible that the mouse’s behaviour is rooted in these responses of hoarding, burying and generally manipulating its environment. All those objects in the mouse’s territory may have triggered confusion, leading the mouse to stash them somewhere it perceives as safe.</p>
<p>So animals are lot tidier than you think and not just this one mouse. Cleanliness is a virtue for a whole host of critters.</p>
<h2>1. Rattlesnakes</h2>
<p><a href="https://bioone.org/journals/the-southwestern-naturalist/volume-60/issue-4/0038-4909-60.4.374/Habitat-Manipulation-in-Hunting-Rattlesnakes-iCrotalusi-Species/10.1894/0038-4909-60.4.374.short">Rattlesnakes</a> lack limbs but still tidy their hunting grounds using their triangular heads and muscular necks to move aside grass. </p>
<p>Decluttering their space may give them a clearer path to potential prey – extremely beneficial for a predator that cannot correct its aim after launching an attack.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265286/original/file-20190322-36279-10d9cld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A rattlesnake flattens and shifts grass aside to get a clear shot at prey.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/farmboyted/14617656300/in/photolist-ogHiWU-9jw6rM-dCfWfn-6y1ck2-c2CDiY-RGff8s-bG6tL6-c2CEbJ-9jzc1o-9w5Yfp-6sxh9w-ogHrdC-cgaB7m-bEwkSw-9JbsYF-foqXDe-6Cmu9U-bwJnLm-fLb2J6-nqk2Cj-ym6-9jw5Zi-ym8-4r8K3z-eANoh-9JehDw-UguVim-3nXx8s-4K1mgu-fogVFW-q6C2jS-ym7-6xSBRx-2d2p5Wr-9jw5Ev-BcT-QbmR2k-9Bnf6F-9jDYMa-9jDYrK-8cCaYz-mGPGL-bVzTZz-4qEDUu-o2NHhu-7K7Luz-e9yo9a-9jDYHe-FLJo4-cU9sFW">Flickr/Farmboyted</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>2. Songbirds</h2>
<p>Songbirds are known to haul their chicks’ “faecal sacs” and drop them outside the nest. <a href="https://www.jstor.org/stable/1370361?seq=1#page_scan_tab_contents">Bluebirds</a> have been seen draping faecal sacs on electric wires, fence posts and utility poles. The birds are quite strict at removing faeces, uneaten food and dead nestlings immediately, to prevent infection and to make the nest harder for predators to detect.</p>
<h2>3. Ants</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=795&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=795&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=795&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=999&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=999&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265292/original/file-20190322-36244-y7lxvm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=999&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A plaster cast of an ant colony, with visible tunnels and chambers.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Ant_colony#/media/File:Ant_Nest.jpg">Shaners Becker/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The risk of disease is especially serious for social animals. Social insects such as ants and bees live in large numbers within very confined spaces, making them vulnerable to contagions. It is for this reason that many <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118376">ant species</a> carry their dead out of the nest rather than leaving the corpses to fester in the tunnels. </p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2014.0306">One study</a> found that if ants were prevented from removing the dead bodies, they were more likely to die. However, Indian jumping ants have a slightly different method – their nests include a “rubbish” chamber which is filled with dead ants, left over prey and faecal matter. These chambers are staffed by a “sewage crew” of maggots that eat the refuse and prevent the chamber getting clogged.</p>
<h2>4. Naked mole rats</h2>
<p>Naked mole rats also live underground and follow a similar system to the ants. They build special toilet areas in their burrows, and when these are full, “waste worker” mole rats plug it with soil and dig a new one. Mole rats are quite meticulous when it comes to their tunnels – whisking away any unruly roots, pebbles and other litter in the passageways. </p>
<p><a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1971.tb04544.x">In one study</a>, scientists planted cables and a thermometer in a mole rat burrow, which were promptly cleared away by the “cleaning crew”.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/jin0dGcFjao?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>5. Damselfish</h2>
<p>For those of you who watched the BBC’s Blue Planet II, you may remember the footage of the garibaldi damselfish tirelessly removing sea urchins from their nest areas, only to find the next day that it was again covered in sea urchins. </p>
<p>Much of the work of rearing offspring is handled by the male. Upon becoming an adult, a male garibaldi will <a href="https://www.nps.gov/chis/learn/nature/garibaldi.htm">select a promising stretch of reef</a> where he will live for the rest of his life. In addition to removing sea urchins from their nest areas, the garibaldi will remove debris, sea stars that wander along, and gnaw away all the plant growth except for a few species of red algae. These he trims so they are about an inch long, which is perfect for the eggs to rest in.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"934878000834842624"}"></div></p>
<p>Just like physical traits, behavioural traits aren’t just influenced by the environment, they can also be inherited. Certain traits make some individuals more likely to reproduce and pass on their genes than others – such as an insistence on cleanliness to prevent disease or predation. As much as we like to think that humans are special and unique, it’s worth recalling the words of Charles Darwin, who said: “The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.”</p><img src="https://counter.theconversation.com/content/114040/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The mouse who tidied the shed he lives in fascinated human viewers, but cleanliness isn’t a virtue unique to humans.Sophia Daoudi, Lecturer in Psychology, University of StirlingJan Hoole, Lecturer in Biology, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/921902018-03-05T15:00:47Z2018-03-05T15:00:47ZFrom foe to friend: how carnivores could help farmers<figure><img src="https://images.theconversation.com/files/208633/original/file-20180302-65533-1gbn2qm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Species like the large spotted genet were commonly found in cropping areas.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Across the globe, the numbers of carnivore species such as <a href="https://doi.org/10.1098/rsos.161090">leopards</a>, <a href="https://portals.iucn.org/library/node/8500">dingoes</a>, and <a href="https://doi.org/10.1111/j.1365-2907.2011.00207.x">spectacled bears</a> are rapidly <a href="https://doi.org/10.7717/peerj.1537">declining</a>. The areas they occupy are also <a href="https://doi.org/10.1073/pnas.1611122114">getting smaller</a> each year. This is a problem, because carnivores are incredibly important to ecosystems as they may provide <a href="https://doi.org/10.1126/science.1241484">services</a> such as biodiversity enhancement, disease regulation, and improving carbon storage. And that, in turn, is <a href="https://doi.org/10.1126/science.aai9214">important to human wellbeing</a>. </p>
<p>But convincing people to conserve wildlife based on these indirect benefits can be challenging – particularly in the case of farmers. After all, carnivores such as leopards can pose a <a href="https://doi.org/10.1111/cobi.12959">threat to livestock</a>, livelihoods, and sometimes even <a href="https://doi.org/10.1038/srep20552">lives</a>. So interactions between farmers and carnivores have typically been framed as a conflict.</p>
<p>Farmers often <a href="https://doi.org/10.1016/j.jnc.2017.03.002">overestimate</a> <a href="https://doi.org/10.1016/j.jnc.2017.03.002">these threats</a>. For many, the response is to kill carnivores – even those that are not eating livestock. This is one of the main reasons why <a href="https://doi.org/10.1126/science.1241484">carnivores are in crisis</a>. </p>
<p>This could change if people were aware of the more <a href="https://doi.org/10.1017/S0030605307001779">tangible benefits</a> that carnivores could provide. <a href="https://doi.org/10.1016/j.ecoser.2017.12.006">Our new study</a> showed that far from causing problems for farmers, carnivores could actually be beneficial by controlling rodent pests.</p>
<h2>Rodents and carnivores</h2>
<p>There’s a desperate <a href="https://theconversation.com/why-controlling-rats-on-small-scale-african-farms-is-vital-for-food-security-79865">need for farmers to control rodents</a> because they <a href="https://doi.org/10.1371/journal.pone.0174554">destroy 15% of the crops</a> growing in African fields. The most common solution is to use <a href="https://www.cabi.org/cabebooks/ebook/20153154910">poison</a>. But this can be expensive and can kill many other species. On top of this, rodents eventually become resistant.</p>
<p>We set out to find out whether carnivores that eat rodents were found naturally on smallholder farms. We set camera traps on land used for cropping in South Africa, areas used to graze cattle (which was less disturbed than cropland), and among houses in village settlements. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=520&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=520&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208017/original/file-20180227-36671-1i28wg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=520&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A cape fox (Vulpes chama) on a maize farm feeding on Gerbilliscus, a common rodent pest in South Africa’s grain areas.</span>
<span class="attribution"><span class="source">Lourens Swanepoel</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We found nine species of carnivores in the camera trap pictures. Rodents are an important part of the diet of seven of the nine, including the striped polecat, honey badger, and African civet. To our surprise, we found that the <a href="https://doi.org/10.1016/j.ecoser.2017.12.006">highest number of carnivore species</a> were often found in the cropping area, which included species such as the large spotted genet and slender mongoose. </p>
<p>So not only are carnivores present on farmers’ fields, but it’s likely that they are also controlling rodents that would otherwise damage crops. But more research is needed to confirm this.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=239&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=239&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=239&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=300&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=300&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208042/original/file-20180227-36686-1b2wr9i.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=300&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Infographic summarising the findings of the study of rodent control by carnivores on South African farms.</span>
<span class="attribution"><span class="source">Sam Williams</span></span>
</figcaption>
</figure>
<p>We set about establishing whether people were aware of the potential connection between the presence of carnivores on their farms and rodent control. During a series of interviews it quickly became clear that even though some people believed that carnivores ate rodents, they still had negative perceptions and often <a href="https://doi.org/10.1016/j.ecoser.2017.12.006">killed them</a>.</p>
<h2>Big potential</h2>
<p>The idea to use natural predation to control rodents is not <a href="https://www.sciencedirect.com/science/article/pii/S1049964416301256">new</a>. But to use mammalian predators to assist in biological control of rodent pests has often been neglected in <a href="https://www.nature.com/articles/s41559-017-0421-2">conservation circles</a>. As such there is great potential for carnivores to help farmers, but for this to work, farmers would need to stop killing them. </p>
<p>Changing these perceptions would take a lot of work. But efforts to change African perceptions about predatory birds, particularly barn owls, <a href="http://wiredspace.wits.ac.za/handle/10539/5067">have been successful</a> in some South African townships. Successful approaches to change community attitudes has often relied on education programmes through local schools. Bringing owls, snakes and other predators to primary schools can help raise awareness among children, who then go home and educate their parents, ultimately breaking down widely held superstitions. </p>
<p>If education campaigns could convince farmers to kill fewer carnivores, carnivores might just repay the favour by doing a better job of controlling rodents in crop fields. This could lead to less reliance on poisons, avoiding unnecessary killings and costs. </p>
<p>If successful, this could help farmers to save money, while working in a much more environmentally friendly way. This really could be a win-win situation for both people and wildlife, and it shows that interactions between people and carnivores on farmland can be much more nuanced and positive than the traditional image of conflict. </p>
<p>Finding new ways in which people and wildlife can coexist will be essential to lessen the impact of the growing human population on the ecosystems on which humans depend.</p><img src="https://counter.theconversation.com/content/92190/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sam Williams receives funding from the University of Venda postdoctoral grant. He is affiliated with the University of Venda and Durham University.</span></em></p><p class="fine-print"><em><span>Lourens Swanepoel receives funding from the National Research Foundation (NRF RSA), University of Venda, International Foundation for Science and The African Union. He is affiliated with the University of Venda and the African Institute of African Conservation Ecology. </span></em></p><p class="fine-print"><em><span>Steven Belmain currently receives funding from The McKnight Foundation, the World Bank and The African Union. He is affiliated with the Natural Resources Institute, University of Greenwich.</span></em></p>Instead of causing problems for farmers, carnivores could actually be beneficial by controlling rodent pests.Sam Williams, Postdoctoral Research Fellow in the Department of Zoology, University of Venda, and Honorary Research Fellow in the Department of Anthropology, Durham UniversityLourens Swanepoel, Associate lecturer, University of VendaSteven Belmain, Professor of Ecology, Natural Resources Institute, University of GreenwichLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/836582017-10-30T12:22:56Z2017-10-30T12:22:56ZUnsuitable antivenoms are being sold in Africa, costing lives<figure><img src="https://images.theconversation.com/files/192005/original/file-20171026-13309-musqyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Echis_, also known as the saw-scaled viper, dominates snakebite statistics and kills more people annually than any other.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Snakes bite more than <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050218">5 million people every year</a>. Of these, around 1.8 million people are envenomated and over <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050218">94,000 are killed</a>. These statistics suggest that snakebite is one of the most <a href="http://www.who.int/snakebites/news/Snakebite_under_spotlight_in_Oxford/en/">neglected tropical diseases</a>. </p>
<p>But getting accurate statistics is incredibly difficult. Many bites go unreported, with as few as 8.5% of snakebite victims <a href="http://www.tandfonline.com/doi/abs/10.1080/00034983.1980.11687380">seeking medical treatment</a>. In Africa snakebite probably kills over <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050218">30 000 people per year</a>. This is <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0000851">proportionally more</a> than in most other regions around the world. A large percentage of these deaths can be attributed to one genus of snake, <em>Echis</em>. </p>
<p>Also known as the saw-scaled viper, <em>Echis</em> can <a href="http://www.megasphera.cz/africanvenomoussnakes/images/Echis/Mapa_Efy_V.jpg">be found</a> throughout sub-Saharan Africa north of the equator and in parts of Asia and the Middle East. This small viper dominates snakebite statistics and kills more people annually than any other. For example, <em>Echis ocellatus</em> is responsible for as many as <a href="https://www.ncbi.nlm.nih.gov/pubmed/9129531">95% of snake bites in northern Nigeria</a>.</p>
<p>Many of the toxins in their venom target the blood to induce clotting. For humans, this causes a potentially lethal condition called <a href="http://www.sciencedirect.com/science/article/pii/S0887796314000972#bb0010">“venom-induced consumption coagulopathy”</a>, more commonly called VICC. This disrupts the body’s ability to regulate blood flow and results in severe internal bleeding. Haemorrhage, stroke, and shock are typically the cause of death following VICC. Antivenom is the only effective antidote.</p>
<p>But the continent is experiencing an <a href="http://www.nature.com/news/africa-braced-for-snakebite-crisis-1.18357">antivenom crisis</a>. This crisis is a result of the <a href="https://theconversation.com/the-african-snakebite-crisis-is-nothing-new-weve-been-worried-about-antivenom-for-decades-47293">discontinuation of a key antivenom</a> in Africa, <a href="http://www.toxinfo.org/antivenoms/productinfo/FAV-AFRIQUE.html">Fav-Afrique</a>. Fav-Afrique was very effective at treating snakebites in Africa. Some clinics reported a <a href="https://www.ncbi.nlm.nih.gov/pubmed/10674688">100%</a> success rate when using this antivenom. But the antivenom’s manufacturers, Sanofi-Pasteur, stopped production of Fav-Afrique after claiming they were <a href="http://www.bbc.com/news/health-34176581">priced out of the market</a>.</p>
<p>The disappearance of Fav-Afrique from African clinics partly explains the exceptionally high rates of snakebite death on the continent. It has seen an increase in the use of cheaper, Indian-produced antivenoms - many of which appear to be <a href="http://www.sciencedirect.com/science/article/pii/S0041010113000147">largely ineffective</a>. </p>
<p>To investigate the issue further, <a href="http://www.sciencedirect.com/science/article/pii/S0378427417312675">we conducted a comparison of four antivenoms</a> that are commonly used to treat <em>Echis</em> bites on the continent. Two were made using Indian <em>Echis</em> venoms and two made using African <em>Echis</em> venoms. We tested these antivenoms against venom samples from ten different populations of <em>Echis</em> across their distribution, from Africa to Asia. </p>
<h2>Comparing antivenoms</h2>
<p>We first added the venom to human <a href="http://www.redcrossblood.org/learn-about-blood/blood-components/plasma">blood plasma</a> and measured the rate at which each venom induced a blood clot. We then repeated the experiment, but with an additional step. Before adding the venom to the plasma, we mixed the venom and antivenom. This step was to give the antivenom a chance to bind with the venom toxins and neutralise their harmful activity on the blood. We assessed the effectiveness of the antivenoms by looking at how well they were able to slow the clotting caused by the venom when compared to our first experiment. </p>
<p>What we found was alarming. Despite the antivenoms being marketed as species-specific (that is, able to treat the bite of a given species), we found extreme region-specific variability in their effectiveness. This means that the performance of the antivenoms varied based on the geographical origin of the venoms, even within a single species. </p>
<p>The Indian-made antivenoms, common throughout Africa because they are affordable, showed little-to-no neutralisation of the African <em>Echis</em> venoms. Even the venoms of some Indian <em>Echis</em> populations showed limited response to the Indian antivenoms. </p>
<p>Clinical case statistics support our findings. After switching to an Indian-produced antivenom following the discontinuation of Fav-Afrique, some African clinics have recorded a horrific <a href="https://academic.oup.com/trstmh/article/102/5/445/1921278/Failure-of-a-new-antivenom-to-treat-Echis">7</a> to <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0003896">20-fold</a> increase in case death rates.</p>
<h2>Why such variability in the antivenoms?</h2>
<p>Antivenoms are developed by injecting a small amount of venom from either one or from multiple species (to produce “monovalent” or “polyvalent” antivenom, respectively) into a host animal, such as a horse. The animal’s immune system responds by producing antibodies that recognise and fight those venom toxins, much like what happens in our bodies when we get a vaccine. These antibodies are extracted and purified. The resulting antivenom is then marketed as being able to treat a bite by the species whose venom was used during its production. </p>
<p>This process is effective and reliable when venom composition does not differ much between individual snakes. Antivenoms may even be effective in treating the bite of a <a href="http://www.sciencedirect.com/science/article/pii/S0041010109002141">closely related snake species</a>. Unfortunately, this is not the case for <em>Echis</em> as their venom composition varies between populations. </p>
<p>This is partly thought to be an <a href="http://pages.bangor.ac.uk/%7Ebss166/Publications/2009_Barlow_Echis_scorpions_FirstCite.pdf">evolutionary adaptation linked to diet</a>. A key function of snake venom is to assist in prey capture. The toxins in venom do this by targeting specific parts of the prey’s physiology, such as the blood or the nerves, to disrupt normal body function and immobilise the animal. </p>
<p>Different <em>Echis</em> populations feed on different prey types. For example, some feed mostly on vertebrates such as rodents or lizards, while others prefer invertebrates such as scorpions. The physiology of these prey animals differs, and this dictates what makes a toxin effective for predation. This could be why some populations have evolved <a href="http://www.pnas.org/content/111/25/9205.full.pdf">different sets of toxins</a>.</p>
<p>From a medical perspective, this means that the antibodies in an antivenom may not be able to adequately recognise and fight all the harmful toxins in the venom. The outcome for patients and clinicians is variable or reduced antivenom effectiveness between regions. </p>
<p>Our results show the failings that come from using a geographically restricted range of antivenoms and marketing them inappropriately. Given the seriousness of snakebite in Africa and around the world, this puts the pressure firmly on antivenom manufacturers to develop, market, and distribute their antivenoms responsibly.</p><img src="https://counter.theconversation.com/content/83658/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bianca op den Brouw does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Indian-made antivenoms, common throughout Africa because they are affordable, showed little-to-no neutralisation of the African Echis venoms.Bianca op den Brouw, PhD Candidate in Toxinology, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/798652017-08-02T15:45:02Z2017-08-02T15:45:02ZWhy controlling rats on small-scale African farms is vital for food security<figure><img src="https://images.theconversation.com/files/180505/original/file-20170801-21062-ppzt0i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In many parts of Africa rodents often cause crop losses.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><a href="http://www.pnas.org/content/113/52/14964.short">Recent analysis</a> suggests that Africa will only be able to achieve food security if it invests in crop intensification like increased fertiliser and pesticide input per hectare. But the expansion of agricultural production areas can also improve this. </p>
<p>A complicating factor in African agriculture is that most of the production comes from relatively <a href="http://www.sciencedirect.com/science/article/pii/S0305750X15002703">small farms</a>. Most of these are less than 2 hectares in size. This is much smaller than in Europe and the Middle East where most farms are greater <a href="http://ec.europa.eu/eurostat/statistics-explained/index.php/File:Distribution_of_holdings_and_utilised_agricultural_area_by_size_class_(utilised_agricultural_area),_EU,_2005_and_2010.png">than 10 hectares</a>. In Latin America most farms <a href="http://www.globalagriculture.org/report-topics/industrial-agriculture-and-small-scale-farming.html">exceed 50 hectares</a>.</p>
<p>This means that addressing issues that affect small scale farmers’ productivity can play an important role in food security. Most farmers simply can’t afford pest management control. Often, these methods are lacking in rural areas. And where there are products it can be adulterated or misused. </p>
<p>Agricultural pests are one of the key factors affecting small holder farmer production. In many parts of Africa large population outbreaks of rodents occur often and can sometimes lead up to <a href="http://books.irri.org/9789712202575_content.pdf">100% crop loss</a>. Rodents can damage nearly every crop people try to grow. It’s often difficult to measure chronic damage because it happens over the entire growing season and even after the crop is harvested.</p>
<h2>The neglected rodents</h2>
<p>Efforts to control pests face a number of challenges. Firstly, management is often limited, because of the high cost of herbicides, insecticides and rodenticides. On top of this they aren’t readily available in local farming areas. And most pest control focuses on invertebrate pests like stem borers, armyworm and locusts. Very little attention is paid to vertebrate pests like rodents or birds like the <a href="http://www.irinnews.org/news/2009/08/19">red-billed quelea</a> (<em>Quelea quelea</em>).</p>
<p>Rodents are a particularly important group of pests. Agriculturally, they can inflict considerable economic damage because of their abundance, diversity, feeding habits and high reproduction abilities. </p>
<p>Research on rodent pest control tends to be neglected. But some community based development programmes are looking at how rodents can be controlled using <a href="http://projects.nri.org/ecorat">ecological methods</a>. <a href="https://www.youtube.com/watch?v=nWTC9ZE25EQ">Ecologically-based rodent management</a> involves, firstly, increasing our understanding of their population biology, social behaviour, taxonomy and community ecology. These insights can then be used to develop effective and sustainable management strategies. This approach has been effective in reducing pest damage as well as <a href="http://www.sciencedirect.com/science/article/pii/S1573521404800113">reducing reliance on rodenticide poisons</a> in many countries. </p>
<p>There is little data on the effects of pest control on rodents, particularly when it comes to small holder farming systems. To gain a better understanding we did a <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0174554">systematic review</a> on the effect of rodent pests on small holder farming in Africa and the island nation of Madagascar. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=562&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=562&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180573/original/file-20170801-22175-4pbx7v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=562&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The damage to maize caused by rats.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<h2>Rodent management in Africa</h2>
<p>Our review highlighted several important findings. We found median crop losses (midpoint of reported losses) attributed to rodent pests were around 15%. This has a significant impact on small holder grain yields and is comparable to losses from cereal stem borers in Africa where much greater investments have been made in <a href="http://onlinelibrary.wiley.com/doi/10.1111/een.12216/full">control programmes</a>.</p>
<p>But there was a big discrepancy in estimated and reported losses, which highlights the importance of standardising research protocols. For example, very little research has been done to try and find a link between rodent density to crop impact. This limits the setting of reasonable management thresholds on when to control rodents based on their density. </p>
<p>Most importantly, we found a paucity of research investigating effectiveness of control measures on rodent pests.</p>
<p>We made several detailed recommendations that we feel will improve the robustness of rodent pest research. The most important ones included the fact that researchers must adopt a “meta-analytic” <a href="https://link.springer.com/chapter/10.1007/978-3-319-55895-0_25">framework</a>. For example, they must place their study in the context of prior literature and they must report on the effect of rodent control, particularly making the comparison between studies and strategies more explicit. This framework has been successfully applied to other evidence based research fields <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049418">like medical research</a>. </p>
<p>Another was that researchers and funding organisations must be encouraged to establish and fund <a href="https://academic.oup.com/bioscience/article-abstract/67/3/271/3057250/Long-Term-Studies-Contribute-Disproportionately-to?redirectedFrom=fulltext">long-term studies</a>. Once a firm foundation has been established on understanding the drivers of population cycles of the dominant rodent pest species, other important aspects like management and community ecology can be successfully developed. </p>
<p>For example, in some African countries – like Tanzania – there have been great improvements in understanding the ecology of pest rodent species. Researchers showed that rainfall plays an important role in predicting rodent pest outbreaks. This facilitated regional planning to control rodent pests in agricultural areas. </p>
<p>We also found that researchers must focus more on empirical treatment control studies that test a management action compared to no management actions. These must be done with suitable replication that investigates management actions on rodent pest populations and associated crop losses. For example, our <a href="http://www.sciencedirect.com/science/article/pii/S1049964416301256">recent meta-analysis showed</a> that avian predators, like barn owls, can reduce rodent pests.</p>
<p>Lastly, we suggest that ecologically based rodent management activities and research should be carried out by multidisciplinary and interdisciplinary teams. In this way research can be sustained over a longer period if there’s collaboration, knowledge is transferred and communities are involved.</p><img src="https://counter.theconversation.com/content/79865/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lourens Swanepoel receives funding from Sasol Agricultural Trust (South Africa), International Foundation for Science (D/4984-2), European Union through its ACP S & T programme (StopRats; FED2013-330223; <a href="http://www.acp-hestr.eu/">http://www.acp-hestr.eu/</a>). He is affiliated with the African Institute for Conservation Ecology and Genetics (AICEG) (Not for profit organization).</span></em></p><p class="fine-print"><em><span>Steven Belmain currently receives funding from the McKnight Foundation, the European Development Fund and the Netherlands Organisation for Scientific Research.</span></em></p>Agricultural pests are one of the key factors affecting small holder farmer production. Focus is normally put on invertebrate pests, but rodents can do severe damage to crops as well.Lourens Swanepoel, Associate lecturer, University of VendaSteven Belmain, Professor of Ecology, University of GreenwichLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/644962016-09-27T16:07:18Z2016-09-27T16:07:18ZThe survival secrets of tiny mammals that could help them avoid extinction<figure><img src="https://images.theconversation.com/files/138476/original/image-20160920-16646-7m4m7f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Grey Mouse Lemurs enter torpor to conserve water.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We live in a changing world – and <a href="http://www.sciencedirect.com/science/article/pii/S2213305413000404">humans are the cause</a>. Habitat loss and fragmentation, pollution, the spread of invasive species, over-harvesting, pollution and climate change are just some of the problems. </p>
<p>It could be argued that the current changes to the Earth’s climate are part of a pattern that has gone on over aeons. <a href="http://www.indiana.edu/%7Egeol105/images/gaia_chapter_4/milankovitch.htm">Milankovitch’s cycles</a>, for example, describe how changes in the Earth’s movements, like the shape of its orbit around the sun or how much it is tilted on its axis, influence the climate. These changes occur at predictable intervals of 10 000 to 100 000 years. </p>
<p>But there is a growing consensus that the current rate and unpredictability of environmental change is <a href="http://science.sciencemag.org/content/299/5615/2005">unprecedented in Earth’s history</a>.</p>
<p>If humans are indeed driving the <a href="https://www.sciencedaily.com/releases/2015/06/150619152142.htm">sixth mass extinction</a>, what hope is there for hundreds of thousands of animal species? </p>
<p><a href="https://uanews.arizona.edu/story/ua-study-evolution-too-slow-to-keep-up-with-climate-change">A recent study</a> suggests that the majority of vertebrate species will not be able to evolve at a rate capable of withstanding current environmental change. This is because evolution is a slow process. It takes time for organisms to adapt.</p>
<p>As is already clear, some species are simply not going to be able to adapt. Extinction of species is something we have come to accept. And it’s not only the iconic species that are at risk. The <a href="https://www.uq.edu.au/news/article/2016/06/barrier-reef-rodent-first-mammal-declared-extinct-due-climate-change">first species to be declared extinct due to climate change</a> was a mouse, the Bramble Cay mosaic-tailed rat.</p>
<p>But some mammals might survive, or even thrive, for reasons that aren’t immediately obvious. It is worthwhile understanding what these are by <a href="http://www.journals.uchicago.edu/doi/abs/10.1086/686810">taking a different approach to how species are studied</a>. </p>
<h2>Thinking outside the box</h2>
<p>Animals have a range of adaptations that could help them cope. </p>
<p>Some species are able to migrate or shift their home ranges, evading unfavourable environments. For example, several rodent and shrew species in Yosemite National Park have shown <a href="http://science.sciencemag.org/content/322/5899/261">substantial range shifts</a>. This has been in response to global warming, but is clearly part of a pattern of behaviour that’s simply being applied to current circumstances.</p>
<p>Other coping mechanisms include mammals being able to secrete vasopressin, an antidiuretic hormone. This helps them to reabsorb water from the kidneys in the event of drought. <a href="http://br9xy4lf5w.scholar.serialssolutions.com/?sid=google&auinit=U&aulast=Shanas&atitle=Diet+salinity+and+vasopressin+as+reproduction+modulators+in+the+desert-dwelling+golden+spiny+mouse+%28Acomys+russatus%29&id=doi:10.1016/j.physbeh.2004.03.002&title=Physiology+%26+behavior&volume=81&issue=4&date=2004&spage=645&issn=0031-9384">Vasopressin</a> is released by the pituitary gland in response to water restriction. It stimulates contraction of the glomerular arterioles in the kidney, facilitating reabsorption of water in the collecting ducts. This could help with conserving water in the short-term. </p>
<p>Animals may also have <a href="http://rspb.royalsocietypublishing.org/content/205/1161/581">exaptations</a>, traits that evolved in response to past environments, that could be useful under changing conditions. An example is the <a href="http://link.springer.com/article/10.1007/s003600000140">eastern rock sengi, which enters torpor</a>, a state of inactivity like hibernation, in response to food restriction. Similarly, the <a href="http://link.springer.com/article/10.1007/s00114-009-0515-z">grey mouse lemur enters torpor</a>, but it does so to conserve water. So torpor didn’t evolve specifically for animals to cope with drought. But it could be useful if droughts increase.</p>
<p>The problem is that there isn’t a record of every morphological, physiological and behavioural trait of every single species. For example, some species, like the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.1971.tb01735.x/abstract">Spinifex hopping mouse</a>, are well studied, while others, such as the <a href="http://www.iucnredlist.org/details/22802/0">masked white-tailed</a> rat are so secretive that we know practically nothing about them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The African striped mouse survived severe drought by forming non-kin huddling groups.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Another coping strategy could be behavioural flexibility. Animals that are behaviourally flexible <a href="http://www.mdpi.com/2071-1050/5/1/163/htm">can change their behaviour quickly</a> in response to the environment. </p>
<p>A great example is the <a href="http://stripedmouse.com/">African striped mouse</a> from the Succulent Karoo of South Africa. During an <a href="http://jmammal.oxfordjournals.org/content/86/4/757.abstract">extreme drought in 2003</a>, 99% of mice died and the population faced extinction. Food was in short supply and many mice starved. Those that survived had no fat reserves. Being small-bodied, mice lose body heat quickly and, without fat, these mice were at extreme risk of freezing to death at night. </p>
<p>But they survived by forming <a href="http://www.nrcresearchpress.com/doi/abs/10.1139/z06-048#.V93Ya3oXdhA">non-kin huddling groups</a> that changed daily. This allowed them to conserve energy. Although striped mice are social, they normally nest in family groups. Nesting with strangers was a unique response to a stressful situation. </p>
<p>Strange as it may seem, the personality of animals may also affect their ability to adapt. Even within a species, some individuals are more likely to survive than others. For example, <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2008.16567.x/full">red squirrels</a> that are more active and risk-prone have a lower chance of survival. But we know little about which personalities will be better off during environmental change.</p>
<p><a href="http://www.journals.uchicago.edu/doi/10.1086/668204">Aggressive individuals</a> may be able to exploit or dominate limited, uniformly distributed resources, which would be great in simple environments like grasslands. But <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0091718">reactive individuals</a> are more behaviourally flexible, which could promote the discovery and exploitation of new resources. </p>
<p>In reality, it is nearly impossible to conserve species and reduce the rate of extinction if <a href="http://science.sciencemag.org/content/341/6145/504">we can’t predict</a> which species, and which individuals, will be threatened and which will survive. But <a href="http://www.journals.uchicago.edu/doi/abs/10.1086/686810">we can make a start</a> by identifying the stressors that are likely to have the most impact. This would include water availability during drought.</p>
<p>We could then identify traits that can promote survival. We should think outside the box and look for exaptations. It is important to take into account that animals can be flexible. In the end, it’s crucial to remember that populations are made up of individuals, which have different personalities, so some individuals will be better suited for coping than others. It’s important that top-down and bottom-up scientists make a point of talking to each other more.</p><img src="https://counter.theconversation.com/content/64496/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tasmin Rymer is currently employed by James Cook University (JCU), Cairns, Australia, within the College of Science and Engineering. She is also a member of the Centre for Tropical Environmental and Sustainability Science (TESS) at JCU. She is also an honorary research fellow at the University of the Witwatersrand, Johannesburg, South Africa. </span></em></p>Climate change has an impact on small mammals and some battle to survive. But some others have developed intriguing coping mechanisms to survive.Tasmin Rymer, Lecturer College of Science & Engineering, Centre for Tropical Environmental and Sustainability Studies, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/624152016-09-12T01:41:42Z2016-09-12T01:41:42ZScientist at work: Revealing the secret lives of urban rats<figure><img src="https://images.theconversation.com/files/136938/original/image-20160907-25257-1bcwvbu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Public park in Manhattan, home to a rat population with over 100 visible burrows</span> <span class="attribution"><span class="source">Dr. Michael H. Parsons</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In an era when we can decode language among animals and design coatings that make military weapons virtually invisible, it may seem that there are few things science cannot accomplish. At the same time, we are surprisingly ignorant about some things that are much more ordinary. For me, perhaps the most intriguing example is city rats, which in many ways are the most important species of urban wildlife in our increasingly urbanized world. </p>
<p>Because rats are small, vigilant and live mainly underground, even behavioral ecologists like me know remarkably little about how they move through cities and interact with their environments. That’s a problem because rats foul our foods, spread disease and damage infrastructure. As more people around the world move to densely packed cities, they become increasingly vulnerable to rat behaviors and diseases. That makes it critically important to understand more about rats and the pathogens they carry. </p>
<p>I decided to study urban rats to help fill some gaps in our knowledge of how they use their sense of smell to seek favored resources (food and potential mates), and how this attraction influences their fine-scale movements across particular types of corridors. </p>
<h2>Small animals with big impacts</h2>
<p>Rats like to feed on small quantities of human rubbish while remaining just out of sight, so they have been associated with humans since the rise of agriculture. The ancestors of today’s urban rats followed humans across the great migratory routes, eventually making their way by foot or ship to every continent. </p>
<p>In cities, rats can enter buildings through openings as small as a quarter. They also may “vertically migrate” upward and enter residential dwellings <a href="https://www.youtube.com/watch?v=0t2VPBF6Kp4">through toilets</a>. Because rats often make their way into homes from parks, subways and sewers, they can transport microorganisms they pick up from decomposition of wastes, thus earning the colloquial nickname of “disease sponges.” </p>
<p>Unlike humans, rats are not limited by the density of their population. In population biology, they are referred to as an <a href="https://www.britannica.com/science/r-selected-species">“r-adapted species,”</a> which means they mature rapidly, have short gestation periods and produce many offspring. Their typical life span is just six months to two years, but a female rat can produce up to 84 pups per year, and pups reach sexual maturity as soon as five weeks after birth. </p>
<p>Like other rodents (derived from the Latin word “rodere,” to gnaw), rats have large, durable front teeth. Their incisors rank at 5.5 on the Mohs scale, which geologists use to measure minerals’ hardness; for comparison, iron scores around 5.0. Rats use their constantly growing incisors to gain access to food. They can cause structural damage in buildings by chewing through wood and insulation, and trigger fires by gnawing on wiring. In garages, rats often <a href="http://www.popularmechanics.com/cars/how-to/a9998/what-happens-when-a-rat-decides-to-live-in-your-car-16393667/">nest inside cars</a>, where they will also chew through insulation, wires and hoses.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/136789/original/image-20160906-25260-l0joa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="http://www.nature.nps.gov/geology/education/concepts/minerals.cfm">National Park Service</a></span>
</figcaption>
</figure>
<p>In addition to causing physical damage, rats spread diseases directly by passing infectious agents through their blood, saliva or wastes, and indirectly by serving as hosts for disease-carrying arthropods such as fleas and ticks. They are known vectors for Lyme disease, Rocky Mountain spotted fever, Toxoplasma, Bartonella, <a href="http://allafrica.com/stories/201608220314.html">Leptospira</a> and other microorganisms, many as yet unnamed. A seminal 2014 study <a href="http://mbio.asm.org/content/5/5/e01933-14.short">found 18 novel viruses</a> in 133 rats collected in Manhattan. </p>
<h2>Studying rats in the city</h2>
<p>Although they are abundant, wild rats are exceptionally difficult to study. They are small, live mainly underground and are active at night, out of most humans’ sight. When people do see rats they are most likely to notice either the sickest or the boldest individuals – such as the <a href="https://www.youtube.com/watch?v=UPXUG8q4jKU">“pizza rat”</a> captured in a 2015 viral video – and make inaccurate generalizations about all rats.</p>
<p>Scientists study animal behavior by analyzing many individuals so that we can detect variations and patterns in behaviors within a population. It may be funny to see a rat drag a whole slice of pizza down subway stairs, but it is much more interesting and useful to know that 90 percent of a population is drawn to foods that are high in fat and protein. To draw conclusions like this, we need to observe how many individual animals behave over time. </p>
<p>Biologists typically track wild animals and observe their movements by capturing them and fitting them with radio or GPS transmitters. But these methods are nearly useless in urban areas: radio waves cannot pass through rebar-reinforced concrete, and skyscrapers block satellite link-ups. </p>
<p>In addition to physical barriers, working with wild rats also poses social challenges. Rats are the pariahs of the animal world: We associate them with filth, disease and poverty. Rather than striving to learn more about them, most people want only to avoid them. That instinct is so strong that last December an Air India pilot flying a Boeing 787 Dreamliner from Mumbai to London made an <a href="http://www.dailymail.co.uk/travel/travel_news/article-3379095/Rats-plane-Packed-passenger-jet-bound-London-forced-make-mid-air-diversion-rodent-spotted-cabin.html">emergency landing</a> after a single rat was spotted on the plane.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/136961/original/image-20160907-16611-1mml7rf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Assessing the health of a rat prior to implanting a microchip.</span>
<span class="attribution"><span class="source">Dr. Michael H. Parsons</span></span>
</figcaption>
</figure>
<p>Working with Michael A. Deutsch, a medical entomologist at <a href="http://www.arrowexterminating.com/">Arrow Pest Control</a>, I have started designing studies to investigate urban rat behavior in situ so that we can, for the first time, learn the histories of individual animals in the wild. We capture rats by luring them with pheromones – natural scents that they find irresistible – and implant radio-frequency identification (RFID) microchips under their skin to identify each animal. This is the same technology that retail stores use to identify commercial products with bar codes and that pet owners can use to identify their dog or cat if it strays. </p>
<p>After we release the microchipped rats, we use scents to attract them back to specific areas and monitor when and how often they return. Using camera traps and a scale that the rats walk across, we can assess their health by tracking weight changes and looking for new wounds and bite marks. We also test their ability to penetrate barriers, such as wire mesh. And we repeatedly collect biological samples, including blood, stool and DNA, to document the rats’ potential to carry pathogens. We have become familiar enough with some rats to give them names that match their unique personalities.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/137276/original/image-20160909-13379-1n3oypr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A newly microchipped rat, groggy but otherwise healthy.</span>
<span class="attribution"><span class="source">Dr. Michael H. Parsons</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In a <a href="http://journal.frontiersin.org/article/10.3389/fevo.2015.00146/full">pilot study</a> published last year, we reported some initial findings. By monitoring individual rats, we learned that males foraged around the clock 24 hours per day, but females did so only during late mornings. Females and males were equally attracted to scents from lab rats, and females responded to pheromones at the same rate as males. </p>
<p>In 2016 we <a href="http://dx.doi.org/10.3389/fpubh.2016.00132">published our detailed methods</a>
as a roadmap that other scientists can use to replicate this research. Using this approach, we believe scientists can learn when and where particular pathogens enter a given rat population. As far as we know, these are the first two studies to analyze wild city rats at the level of the individual in a major U.S. metropolitan area. </p>
<h2>Overcoming taboos against studying city rats</h2>
<p>In doing this research, I have encountered strong social taboos against working with rats. In 2013, while I was seeking opportunities to carry out field research on rats in New York City, I requested access to the CCTV surveillance cameras of <a href="http://forgotten-ny.com/1999/05/the-alleys-of-lower-manhattan-how-did-mill-lane-marketfield-strret-and-theatre-alley-get-their-names">“Theatre Alley,”</a> a narrow lane in Manhattan’s Financial District where rats scurried at will. Just a few weeks later, I learned that Theatre Alley had been hastily cleaned, changing the setting forever and removing information that could have provided useful insights into rat movements and behavior.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/137090/original/image-20160908-25257-ab48h6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The feeling isn’t mutual.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/denial_land/2911479223">caruba/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>We have also found that there is little money for this kind of research. Although New York City spends a lot of money training pest control workers and finding and exterminating rat colonies through public institutions such as the <a href="http://www.mta.info/">Metropolitan Transportation Authority</a> and the <a href="http://www1.nyc.gov/site/doh/index.page">Department of Health and Mental Hygiene</a>, there are few opportunities for academic studies. </p>
<p>Officials at public agencies think pragmatically and respond to a specific threat after a problem has been reported. Thus, it is understandable that they may be unreceptive to requests for access to subways for theoretical purposes, or for disease-related surveillance in the absence of a demonstrated threat that may or may not come to fruition. </p>
<p>Instead, Michael Deutsch and I are looking for New York City residents who will allow us to do scientific research in their homes, businesses, apartment buildings and other establishments, without fear of publicity, fines or judgment. To do this work on a larger scale, we need to do more work to build bridges between academic research and front-line public health and sanitation agencies.</p>
<p>In New York alone, up to six million people use the subway system every day, coming into close proximity with rats, and nearly one-fourth of more than 7,000 restaurants inspected so far this year have shown <a href="http://www.theepochtimes.com/n3/2141467-in-new-york-city-rats-and-humans-are-one-for-one-says-rat-expert/?utm_expvariant=D001_01&utm_expid=21082672-11.b4WAd2xRR0ybC6ydhoAj9w.1&utm_referrer=https%3A%2F%2Fnews.google.com%2F">signs of rat or mouse activity</a>. We clearly need to know more about urban rats: how they behave, where they travel, when and where they pick up diseases and how long they spread them, how these diseases affect rats’ health and, eventually, how rats transmit infections to humans.</p><img src="https://counter.theconversation.com/content/62415/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael H. Parsons does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Rats foul our food, spread disease and damage property, but we know very little about them. A biologist explains how he tracks wild rats in New York City, and what he’s learned about them so far.Michael H. Parsons, Scholar-in-Residence, Hofstra UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/573602016-04-08T04:21:39Z2016-04-08T04:21:39ZExplainer: understanding plague in the 21st century<figure><img src="https://images.theconversation.com/files/117864/original/image-20160407-16252-17u3bir.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Uncollected rubbish provides food and shelter for rodents which can spread plague if they pick up the bacteria. </span> <span class="attribution"><span class="source">Reuters/Siphiwe Sibeko</span></span></figcaption></figure><p><em>In medieval times, plague was known as the “black death” and resulted in millions of Europeans dying. Plague still persists in many areas, with the highest annual burden of disease in Africa.
The advent of antibiotics means that milder versions of plague can be treated. But according to the World Health Organization, pneumonic plague is still one of the most <a href="http://www.who.int/topics/plague/en/">deadly infectious diseases</a>. If someone contracts it, they can be dead within 24 hours.
Health and Medicine Editor Candice Bailey spoke to John Frean, Head of the Centre for Opportunistic, Tropical and Hospital Infections at the National Institute for Communicable Diseases in South Africa, about the deadly disease.</em></p>
<p><strong>Why is plague considered dangerous?</strong></p>
<p>Plague is a zoonotic disease caused by the bacterium <a href="http://web.uconn.edu/mcbstaff/graf/Student%20presentations/Y.%20pestis/Yersinia%20pestis.html"><em>Yersinia pestis</em></a>. It is found mainly in rodents and is spread by fleas from rodent to rodent. It can also spread from rodents to humans and other mammals, including dogs and cats. </p>
<p>Rodents are susceptible to plague bacteria and usually become ill or die after they are infected. An outbreak of plague in rodents is recognised by an unusual number of rodents dying. In these situations, rodent fleas are more likely to bite and infect other animals or humans, as their natural hosts have died.</p>
<p>People are at risk of getting plague if they:</p>
<ul>
<li><p>are bitten by rodent fleas that are infected with plague; </p></li>
<li><p>handle rodents that have died from plague, as infected blood or tissue could contaminate skin or be ingested; or</p></li>
<li><p>are in contact with humans or animals infected with plague, as infected pus or sputum droplets could carry the organism.</p></li>
</ul>
<p>If plague is not recognised and treated promptly, it can produce potentially serious or fatal disease. In its pneumonic form, plague may rapidly spread from person to person, which could constitute a public health hazard.</p>
<p><strong>How does plague manifest in humans?</strong></p>
<p>There are three forms of the plague that humans can get, all of which are potentially deadly: </p>
<p><strong>1. Bubonic plague:</strong> This happens after someone is bitten by a flea from an infected rat. There is a sudden onset of fever, chills, headache, weakness and the swelling of lymph nodes (glands) near the bite site. The patient may complain of abdominal pain, nausea, vomiting and diarrhoea. If treated, symptoms resolve in three to five days. If untreated, the disease can become more severe and can be fatal. Complications may include bubonic plague progressing to septicaemic or pneumonic forms, which could result in death.</p>
<p><strong>2. Septicaemic plague:</strong> This may arise as a complication of untreated bubonic plague but could be the first presentation of plague in a person. Aside from the fever, chills, extreme weakness, abdominal pain and shock experienced with bubonic plague, septicaemic plague can also result in bruises and bleeding in organs. Skin and other tissues – especially on the person’s extremities, such as the fingers, toes and nose – may turn black and die. </p>
<p><strong>3. Pneumonic plague:</strong> This can come about after bubonic or septicaemic plague is not treated, but it can also develop when someone inhales infectious droplets from a patient with pneumonic plague. People who have pneumonic plague have a fever, headache, weakness and a rapidly-developing pneumonia. They experience shortness of breath, chest pain, coughing and sometimes bloody or watery sputum.</p>
<p><strong>How common is plague?</strong></p>
<p>Plague has been reported in several African countries in the past decade. These include Madagascar, the Democratic Republic of Congo, Uganda, Mozambique, Malawi, Tanzania, Angola, Namibia and Zimbabwe.</p>
<p>There is currently a plague outbreak in Madagascar that was first reported in December 2013. It is affecting humans and there have been more than 170 cases of bubonic plague and a single case of pneumonic plague reported.</p>
<p>The last case of human plague in South Africa was reported in 1982 in Coega in the Eastern Cape province after being dormant for more than ten years. There were seven laboratory-proven infections and one death.</p>
<p><strong>How is plague diagnosed and treated?</strong> </p>
<p>Symptoms of plague may start showing two to eight days after the person has been exposed to the organism.</p>
<p>Plague may be diagnosed through culture of clinical specimens. For example, pus from the swollen lymph node, or blood or sputum could be cultured. This takes a few days. There are rapid tests that can identify the presence of a specific plague antigen in these samples, but they are generally only available in high plague transmission areas. They are relatively quick. </p>
<p>Plague can also be detected by finding <em>Yersinia pestis</em> antibodies in a blood specimen. Laboratory testing is done in specialised laboratories under strict biosafety conditions. Antibody testing takes a few hours.</p>
<p>Antibiotics are effective to treat all forms of plague and should be started as soon as possible to prevent complications. A vaccine is available for people at high risk, such as laboratory workers, but its effectiveness is not fully known.</p>
<p><strong>Can plague be prevented?</strong></p>
<p>Rodent and flea control, and monitoring of the wild rodent population, are the main measures to monitor the risk of outbreaks. Rodents are trapped and tested for plague antibodies. Their tissues might be cultured if plague infection is strongly suspected. </p>
<p>If there is a positive result, public health measures are implemented to prevent humans becoming infected. These include insecticide spraying in and around dwellings to kill fleas. Rodent surveillance and elimination measures such as trapping and poisoning also take place. Rubbish cleanup is an important element of control as it reduces the availability of food and shelter for rodents.</p>
<p>In South Africa, there are currently two national plague surveillance sites: the Coega area of the Nelson Mandela Bay Metropolitan Municipality in the Eastern Cape, and the City of Johannesburg Metropolitan Municipality in Gauteng province. </p>
<p>A rat that was plague antibody-positive was recently trapped in the greater Johannesburg area in an informal settlement. Although the origin of the rat’s infection is unknown, plague typically survives at low or undetectable levels in wild rodent populations. A wild rodent flea may have been the source. </p>
<p>Public health measures were rolled out by the city’s environmental health officers and to date no further plague-positive rodents have been found. </p>
<p>South Africa has been a plague risk area for many years but the number of animal and human outbreaks dwindled to zero in the past 34 years, so the risk of a major outbreak is low. Environmental health officers are, however, alert to the possibility of new plague outbreaks.</p><img src="https://counter.theconversation.com/content/57360/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Frean previously received funding from the SA Medical Research Council for molecular plague epidemiology research, but the project has terminated.</span></em></p>Plague, one of the deadliest diseases in the world, has been reported in several African countries in the past decade.John Frean, Principal Pathologist and Head of the Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable DiseasesLicensed as Creative Commons – attribution, no derivatives.