tag:theconversation.com,2011:/africa/topics/breeding-program-5719/articlesBreeding program – The Conversation2022-01-12T16:43:33Ztag:theconversation.com,2011:article/1745382022-01-12T16:43:33Z2022-01-12T16:43:33ZRegent honeyeaters were once kings of flowering gums. Now they’re on the edge of extinction. What happened?<p>Less than 80 years ago, regent honeyeaters ruled Australia’s flowering gum forests, with huge raucous flocks roaming from Adelaide to Rockhampton. </p>
<p>Now, there are less than 300 birds left in the wild. Habitat loss has pushed the survivors into little pockets across their once vast range. </p>
<p>Sadly, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320721004821?via%3Dihub">our new research</a> shows these birds are now heading for rapid extinction. Unless we urgently boost conservation efforts, the regent honeyeater will follow the <a href="https://www.pnas.org/content/111/29/10636.short">passenger pigeon</a> into oblivion within the next 20 years. </p>
<p>If we let the last few die, the regent honeyeater will be only the second bird extinction on the Australian mainland since European colonisation, following the <a href="https://theconversation.com/100-years-ago-this-man-discovered-an-exquisite-parrot-thought-to-be-extinct-what-came-next-is-a-tragedy-we-must-not-repeat-171939">paradise parrot</a>. </p>
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<img alt="" src="https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=840&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=840&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=840&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1055&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1055&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440139/original/file-20220110-17-i5hkd0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1055&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Regent honeyeaters are one of the most endangered birds in Australia.</span>
<span class="attribution"><span class="source">Lachlan Hall.</span></span>
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<h2>How did it come to this?</h2>
<p>With vivid yellow and black wings, embroidered body and warty faces, these honeyeaters are among Australia’s most spectacular birds.</p>
<p>John Gould, one of Australia’s earliest European naturalists, observed these birds in “immense flocks amongst the brushes of New South Wales”. He described the regent honeyeater as “the most pugnacious bird he ever saw”, noting they “reigned supreme in the largest, most heavily-flowering trees.” Their success in securing nectar supplies made them vital pollinators. </p>
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Read more:
<a href="https://theconversation.com/only-the-lonely-an-endangered-bird-is-forgetting-its-song-as-the-species-dies-out-156950">Only the lonely: an endangered bird is forgetting its song as the species dies out</a>
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<p>The world Gould saw is sadly a thing of the past. Regent honeyeater populations have plummeted, with the loss of over 90% of their <a href="https://academic.oup.com/jpe/article/5/1/109/1294916?login=true">preferred woodland habitats</a> to farmland. </p>
<p>You might wonder how this could be, given there are still large tracts of forest in Australia. But these are invariably on poorer soils and hilltops. Our remaining forests do not yield the rich nectar regent honeyeaters require for breeding. </p>
<p>As their habitat has declined, the surviving regent honeyeaters have been forced to compete with larger species – without the safety of their huge flocks. The result? The once common species <a href="https://www.tandfonline.com/doi/full/10.1080/01584197.2017.1333392">no longer reigns supreme</a>. </p>
<h2>Gone within 20 years</h2>
<p>Unless conservation actions are urgently stepped up, our research shows these birds will be extinct within 20 years. </p>
<p>We’ve known about the decline of regent honeyeaters since the <a href="https://search.informit.org/doi/abs/10.3316/informit.629962143894936">late 1970s</a>. In response, a recovery team including BirdLife Australia and Taronga Conservation Society launched a <a href="https://www.awe.gov.au/sites/default/files/documents/national-recovery-plan-regent-honeyeater.pdf">long-term recovery effort</a> to protect habitat, plant new trees and release zoo-bred birds. These efforts have slowed but not arrested the decline of these birds. </p>
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<img alt="" src="https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=730&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=730&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=730&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=917&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=917&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439989/original/file-20220110-19-1y7oxfm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=917&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Regent honeyeaters are important pollinators of eucalypts.</span>
<span class="attribution"><span class="source">Liam Murphy.</span></span>
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<p>In 2015, we began a <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.13104">large-scale survey</a> to better understand their population decline. Regent honeyeaters are a notoriously <a href="https://www.difficultbirds.com/about-us">difficult bird</a> to study in the wild. As nomads, they wander long distances throughout their vast range in search of nectar in their <a href="https://woodiwild.org/tree-species/yellow-box-eucalyptus-melliodora/">favoured tree species</a>. Finding these birds is hard enough, let alone monitoring the population in detail.</p>
<p>After six years of intensive fieldwork, and with data from research in the 1990s and long term bird banding, we have finally gathered enough information to be able to understand the challenges for the few remaining wild birds. We now know their <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ibi.12659">breeding success has declined</a> because their nests are raided and the chicks killed by aggressive native species, with <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.12128">noisy miners a particular problem</a>. </p>
<p>We also know the wild birds are <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.0225">losing their song culture</a> because of a lack of older birds for fledglings to learn their songs.</p>
<p>Our fieldwork has given us accurate estimates of vital breeding data, such as how many young birds fledge for each adult female, how many birds are breeding and how well juveniles are surviving. We combined this with data from the decades of monitoring of zoo-bred and released birds to create <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/cobi.13414">population models</a>, which allow us to predict the future for the wild population under different conservation scenarios.</p>
<h2>Habitat is king</h2>
<p>What do the models show? That time is critical. To have any chance of getting the regent honeyeater back, we must build its numbers up enough for them to be able to roam in large flocks for protection. </p>
<p>How? First, we have to nearly double the nesting success rate for both wild and released zoo-bred birds. Too many young birds are dying early. That means we have to find nesting birds early in the breeding season and protect them from noisy miners, pied currawongs and even possums. </p>
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<img alt="" src="https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439991/original/file-20220110-15-qmhcqw.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">
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<span class="caption">Regent honeyeater nests need protection from predators.</span>
<span class="attribution"><span class="source">Nathan Sherwood</span></span>
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<p>Next, we have to boost the numbers of zoo-bred birds released in the Blue Mountains, and maintain these numbers for at least twenty years. Staff at Taronga Conservation Society are preparing zoo-bred birds for the trials of the wild by exposing them to competition in flight aviaries, song tutoring young males and improving <a href="https://www.frontiersin.org/articles/10.3389/fcosc.2021.669563/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Conservation_Science&id=669563">husbandry practices in zoos</a> to increase survival in the wild.</p>
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Read more:
<a href="https://theconversation.com/should-we-cull-noisy-miners-after-decades-of-research-these-aggressive-honeyeaters-are-still-outsmarting-us-169524">Should we cull noisy miners? After decades of research, these aggressive honeyeaters are still outsmarting us</a>
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<p>Finally, our models clearly show regent honeyeaters will only become self-sustaining if we do much more to secure their habitat. Their remaining pockets of habitat are simply too small. We must protect all remaining habitat, restore degraded habitat and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.12878">control noisy miners</a>. </p>
<p>Without habitat, other conservation efforts will be pointless. The honeyeater will simply never reach flock sizes large enough to muscle their way back into the surprisingly competitive business of drinking nectar. </p>
<p>Unfortunately, we continue to destroy essential regent honeyeater habitat in some areas even as we attempt to restore lost habitat elsewhere. For example, if the Warragamba Dam in the Blue Mountains is <a href="https://www.smh.com.au/environment/conservation/cracks-in-warragamba-dam-plan-revealed-by-leaked-documents-20200721-p55e3e.html">raised</a> it will flood essential habitat and make it even harder to bring back our iconic honeyeater. </p>
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<img alt="" src="https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440140/original/file-20220110-19-19g9ykm.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">
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<span class="caption">Ongoing destruction of the habitat of regent honeyeaters is likely to lock-in their extinction.</span>
<span class="attribution"><span class="source">Lachlan Hall</span></span>
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<h2>The status quo is not enough</h2>
<p>For decades, conservationists and researchers have worked to save the regent honeyeater. Despite this tireless work, the species is inching towards the exit. If we maintain the status quo, we will lose it. </p>
<p>We must think bigger. Nest protection and release of zoo-bred birds can help get flock sizes up, but these efforts will be pointless if there are no blossoms for them to drink from. </p>
<p>Like the regent honeyeater, the passenger pigeon sought safety in numbers. We now know its extinction <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320714003401">could have been predicted</a>, if modern risk assessments had been available. Those same assessments and models tell us very clearly what will happen to the regent honeyeater. </p>
<p>It is too late for the passenger pigeon. It is not too late to save the regent honeyeater. But only if we act now. </p>
<p><em>Monique Van Sluys (Taronga Conservation Society) and Dean Ingwersen (Birdlife Australia) contributed to this article</em></p><img src="https://counter.theconversation.com/content/174538/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rob Heinsohn receives funding from the Australian Research Council. The study reported here was funded by an Australian Government Wildlife and Habitat Bushfire Recovery Program grant to Birdlife Australia.</span></em></p><p class="fine-print"><em><span>Dejan Stojanovic receives funding from an Australian Government Natural Heritage Trust grant. </span></em></p><p class="fine-print"><em><span>Ross Crates receives funding from the NSW Office of Environment and Heritage, BirdLife Australia, CWP renewables and the Department of Agriculture, Water and Environment.</span></em></p>These iconic honeyeaters once ruled the flowering gum trees in massive numbers. But habitat loss means they’re on the edge of extinction.Rob Heinsohn, Professor of Evolutionary and Conservation Biology, Australian National UniversityDejan Stojanovic, Postdoctoral Fellow, Australian National UniversityRoss Crates, Postdoctoral fellow, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1739792022-01-06T14:39:16Z2022-01-06T14:39:16ZGreat balls of fire: How heating up testicles with nanoparticles might one day be a form of male birth control<figure><img src="https://images.theconversation.com/files/439249/original/file-20220103-36920-yu4j17.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C9485%2C5800&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Warming the testicles using nanorods affects sperm production.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/great-balls-of-fire--how-heating-up-testicles-with-nanoparticles-might-one-day-be-a-form-of-male-birth-control" width="100%" height="400"></iframe>
<p>Women have a variety of methods for contraception, but only two methods are commonly available to men: condoms and vasectomies. Both methods have their drawbacks. </p>
<p>Condoms can break, and some men <a href="https://doi.org/10.1111/j.1600-0536.1989.tb03173.x">are allergic to the latex in standard condoms</a>. Vasectomies are surgical procedures that can be <a href="https://dx.doi.org/10.4103/1008-682X.175090">painful</a> and <a href="https://dx.doi.org/10.4103/1008-682X.175091">difficult to reverse</a>. </p>
<p>So the search for <a href="https://dx.doi.org/10.4103/2230-8210.102991">alternative male contraceptive options continues</a>, and one method currently being investigated is <a href="https://doi.org/10.1038/nmat3701">nanocontraception</a>.</p>
<h2>An on/off switch</h2>
<p>Nanocontraception is based on the idea that nanoparticles — here, about 100 nanometres in diameter, or roughly one-thousandth the width of a piece of paper or of a strand of human hair — can somehow be delivered to the testicles, where they can be warmed.</p>
<p>If you could warm up the testicles just a bit, you would have a way to turn sperm production on and off at will because the warmer they get, <a href="https://doi.org/10.1530/jrf.0.1140179">the less fertile they become</a>. But it’s a delicate process because the testicles can be irreversibly destroyed if they become too warm; the tissue dies and can no longer produce sperm, even when the testicles return to their normal temperature.</p>
<p>Using nanotechnology to warm testicles was first studied in 2013 on mice by biologist Fei Sun and his multidisciplinary research team. His early experiments <a href="https://doi.org/10.1021/nl400536d">involved injecting nanoparticles directly into mouse testicles</a>. These nanoparticles were long nanorods (or nanocylinders) of gold atoms — imagine a tube 120 gold atoms long with a diameter of 30 gold atoms — coated with a few long polymer chains on their surface. They looked like oblong bacteria with hairs sticking out.</p>
<p>Infrared radiation was then used on the mice’s testicles. This caused the nanoparticles to warm from around 30 C to between 37 and 45 C. The exact temperature depended on both the concentration of nanoparticles injected and the intensity of the radiation.</p>
<p>The radiation caused heat lesions on the skin surrounding the mice’s testicles, so it was assumed that this procedure was painful for the animals, even though there was no reliable way to measure their pain. The researchers decided to look for other ways to inject the nanoparticles.</p>
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<a href="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A hand wearing a latex glove holds a white lab mouse" src="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439252/original/file-20220103-23-e6nw1u.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>
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<span class="caption">Researchers used mice to test nanotechnology as a method of male birth control.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>Iron rods</h2>
<p>In July 2021, Sun’s team <a href="https://doi.org/10.1021/acs.nanolett.1c02181">published a paper on their latest findings</a>. The nanorods in the new method are composed of magnetic iron oxide instead of gold, and they are coated with citric acid instead of ethylene glycol — but they have the same size and shape as the earlier nanorods.</p>
<p>These magnetic nanoparticles were injected into mice’s veins, and then the animals were anesthetized. A magnet was then placed next to their testicles for four hours, drawing the nanoparticles there.</p>
<p>This procedure — injection followed by magnetic targeting — was performed daily for one to four days.</p>
<p>After the last day of treatment, an electric coil was wrapped around the testicles, through which a current was passed. This induced a magnetic field that heated up the nanorods and, therefore, the testicles. Similar temperature increases — from a baseline of 29 C to between 37 and 42 C — were observed through this method. The more days a mouse had been injected with nanorods, the hotter its testicles became.</p>
<p>Hotter testicles led to their atrophy and shrinkage, but they showed gradual recovery both 30 and 60 days after treatment as long as testicle temperatures didn’t reach 45 C. Fertility was down seven days after treatment — in some cases, fertility was completely eliminated — but it also showed gradual (though not complete) recovery after 60 days.</p>
<p>Although fertility was not back to normal levels, there was no noticeable difference in the litter size of females impregnated by the treated mice and no morphological defects were observed in any of the mice pups. There seemed to be no difference in the sperm that did make it through.</p>
<p>And Sun and his colleagues found that, unlike the gold nanorods that stayed indefinitely in mouse testicles, the iron nanorods were gradually eliminated into the liver and spleen, and later fully eliminated from the body. This reduced the risk for long-term toxicity.</p>
<h2>Controlled breeding</h2>
<p>The cost and the irreversibility of surgical castration <a href="https://doi.org/10.1177/1098612X15594994">lead many pet owners to look for alternative methods of contraception</a>. Nanocontraception is ready to be used on household pets, says Sun, and adds that this method is already being used on cats in China. </p>
<p>Surgical castration is less popular in Europe than in North America, so nanocontraception might be of greater interest there, says David Powell, director of the Reproductive Management Center of the Association of Zoos and Aquariums in St. Louis, Mo. “There’s really not a big pet contraception market in the U.S.,” says Powell.</p>
<p>He adds that contraception is not typically used with agricultural animals like sheep and cows. “They are reared for consumption and slaughter, so the agriculture industry is not doing much, if any, research on animal contraception.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A male lion and a cub" src="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439196/original/file-20220103-25-cxsk5y.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>
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<span class="caption">Viable contraception for animals can be a valuable tool for animal conservation and breeding programs.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>“Zoos are a very small market, and so drug companies don’t have a lot of motivation to make animal contraceptives,” says Powell. But some of them do, and the <a href="https://www.aza.org/reproductive-management-center/">Reproductive Management Center</a> collects data to evaluate how contraceptives work on different species.</p>
<p>Nanocontraception could be a part of zoos’ reproductive toolkit one day. But before this happens, says Powell, further studies would need to establish how painful it is and in which species the iron nanorods can be used. Research has indicated that some mammals — such as rhinoceroses, lemurs and dolphins — might accumulate iron, <a href="https://doi.org/10.1638/2011-0152.1">which can be toxic in larger quantities</a>.</p>
<h2>Reversible options</h2>
<p>One potential advantage of nanocontraception is its reversibility, as zoos often try to precisely time breeding events over animals’ life cycles. But just how reversible it is needs further study. All of Sun’s experiments treated mice only once; they were never subjected to a second injection of nanoparticles after their testicles had healed.</p>
<p>Sun’s ultimate goal is human contraception, although he admits that’s still a long way off. As with zoo animals, detailed studies will be required to establish that nanocontraception is not toxic for men. It is also more difficult to put a man under anesthesia for four hours and wrap an electric coil around his testicles than it is to do the same thing on a mouse. Instead, Sun hopes to be able to deliver the magnetic nanorods orally and find another way to direct them to the testicles.</p>
<p>And it is uncertain how many men will be comfortable with shrunken testicles, even if they recover their original size with time. </p>
<p>Until then, better get those condoms out.</p><img src="https://counter.theconversation.com/content/173979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeffrey Mo 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>Growing applications of nanotechnology include using nanorods for male birth control. The technique has had some success in animals, and offers the potential of human male contraception.Jeffrey Mo, Global Journalism Fellow, Dalla Lana School of Public Health, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/966352019-05-20T04:03:42Z2019-05-20T04:03:42ZManaging mutations of a species: the evolution of dog breeding<figure><img src="https://images.theconversation.com/files/259476/original/file-20190218-56220-1789by1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Wire Fox Terrier named King is trotted out before being named Best in Show on the second night of the 2019 Westminster Kennel Club Dog Show.</span> <span class="attribution"><span class="source">JUSTIN LANE/EPA</span></span></figcaption></figure><p>In the first edition of <a href="http://darwin-online.org.uk/EditorialIntroductions/Freeman_OntheOriginofSpecies.html">On the Origin of Species</a>, Charles Darwin mentions dogs 54 times. He does so mainly because the extraordinary variation between dog breeds provides a marvellous illustration of the power of selection. For most of the roughly 15,000 years since their domestication, dogs were selected by humans for their usefulness as hunters, retrievers, herders, guards or companions. </p>
<p>As modern breeds became recognisable, the extent to which a dog aligned with the expected shape, size and coat for its breed (known as “conformation”) became more important. So important, in fact, that just a few years before On the Origin of Species hit the bookshops, the world’s first conformation-based dog show was held in the Town Hall of Newcastle-upon-Tyne in England.</p>
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Read more:
<a href="https://theconversation.com/is-your-dog-happy-ten-common-misconceptions-about-dog-behaviour-97541">Is your dog happy? Ten common misconceptions about dog behaviour</a>
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<p>By 1873, the UK <a href="https://www.thekennelclub.org.uk/our-resources/about-the-kennel-club/history-of-the-kennel-club/">Kennel Club</a> was formed to, among other things, regulate the showing and breeding of dogs. Similar organisations soon followed in other countries. The criteria for judging and breeding for conformation were formalised in breed standards that are now administered by kennel clubs around the world. </p>
<p>Unfortunately, breeding for the standard in some breeds resulted in <a href="https://theconversation.com/vets-can-do-more-to-reduce-the-suffering-of-flat-faced-dog-breeds-110702">serious compromises to health and welfare</a>, especially in cases where the wording of the standard encouraged exaggeration of certain features. </p>
<h2>Breeds to watch out for</h2>
<p>The Kennel Club <a href="https://www.thekennelclub.org.uk/services/public/breed/watch/Default.aspx">Breed Watch</a> has highlighted roughly 15% of breeds as having “breed-specific conformational issues which may lead to health problems” and a further 4% of breeds in which “some dogs have visible conditions or exaggerations that can cause pain or discomfort”.</p>
<p>Fortunately, there is now global coordination in addressing these issues. The <a href="https://dogwellnet.com/">International Partnership For Dogs (IPFD)</a> which works with many of the world’s leading breed-regulating organisations, is highlighting “<a href="https://dogwellnet.com/content/international-actions/extremes-of-conformation-brachycephalics/extremes-of-conformation-dwn-resources-r569/">extremes of conformation</a>”.</p>
<p>Without up-to-date prevalence data on each disorder, we cannot be sure how effective watch lists or changes in breed standards have been in tackling these disorders. Furthermore, in 2009-2010, one of us (Paul McGreevy) helped to show that while <a href="https://www.ncbi.nlm.nih.gov/pubmed/19836981">some of the conformational issues of concern are related to breed standards</a>, others are <a href="https://www.ncbi.nlm.nih.gov/pubmed/19963415">inherited disorders not related to breed standards</a>. </p>
<p>So, even if there were no breed standards and dogs were bred solely for health and welfare, many inherited disorders would still occur. In fact, the vast majority of inherited disorders have nothing to do with conformation.</p>
<p>All inherited disorders (and all desirable inherited traits) are, in essence, the result of random mutations in DNA that have occurred and continue to occur in all species.</p>
<p>The number of known inherited disorders varies enormously among species, mainly reflecting the extent of research effort. For example, the number of single-gene disorders documented in humans is <a href="https://www.omim.org/statistics/geneMap">more than 5,300</a>, whereas the figure for dogs is <a href="https://omia.org">fewer than 300</a>. As many of the inherited disorders that occur in humans could also occur in dogs, the present number for dogs is likely to be just the tip of the iceberg. </p>
<p>A global research effort is providing an ever-increasing number of DNA tests for known canine inherited disorders, enabling (in many cases) elimination of the disorder. National kennel clubs provide <a href="https://www.thekennelclub.org.uk/health/for-breeders/dna-testing-simple-inherited-disorders/worldwide-dna-tests/">useful guidance on testing</a> and <a href="https://www.thekennelclub.org.uk/services/public/mateselect/test/Default.aspx">public access to test results on individual dogs</a>. The IPFD provides global information for breeders on the <a href="https://dogwellnet.com/ctp/">harmonisation of genetic testing for inherited disorders in dogs</a>. </p>
<p>One of us, Paul McGreevy, has been part of an international team that developed a <a href="https://www.ncbi.nlm.nih.gov/pubmed/21742521">risk-assessment criterion</a> for determining priorities for research and control of inherited disorders. A major component of this score is the prevalence of a disorder in a particular breed.</p>
<h2>Estimating the prevalence of disorders</h2>
<p>Fortunately, digital health has arrived in the veterinary sphere and is set to provide, for the first time, comprehensive estimates of disorder prevalence. </p>
<p>Paul is the chair of <a href="http://www.mdpi.com/2076-2615/7/10/74">VetCompass Australia</a>, based on the highly successful <a href="https://www.rvc.ac.uk/vetcompass">UK VetCompass</a> that he helped to establish ten years ago. It’s the first Australia-wide surveillance system that gathers together clinical records on companion animal diseases and treatments. </p>
<p>Bringing together all seven Australian veterinary schools, VetCompass Australia collects clinical records from hundreds of vets across the country for researchers to interrogate. Analysis of these records will reveal trends in the prevalence of inherited and acquired diseases, identify effective treatments, and help vets and breeders improve dogs’ quality of life.</p>
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<strong>
Read more:
<a href="https://theconversation.com/vets-can-do-more-to-reduce-the-suffering-of-flat-faced-dog-breeds-110702">Vets can do more to reduce the suffering of flat-faced dog breeds</a>
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<p>The vision for this surveillance system is that it will one day provide real-time data on the prevalence of each known disorder and show how effective various control strategies are. Real-time data will also sound the alarm on clusters of new disorders as they emerge.</p>
<p>Complementing VetCompass is <a href="http://www.mybreeddata.com/crm/index.html">MyBreedData</a>, a Finland-based website that collects the results of genetic analyses from huge numbers of dogs to identify mutations known to cause particular inherited disorders. Among other things, this information provides early warning signs of which breeds contain which harmful mutations. </p>
<h2>What about hybrid vigour?</h2>
<p>Hybrid vigour for a particular trait is the extent to which, on average, the puppies from the mating of a purebred female from one breed with a purebred male from another breed, are better for that trait than the average of the two parental breeds for that trait.</p>
<p>Evidence from other species suggests that hybrid vigour in dogs could occur to a limited extent in traits related to health, welfare, and fitness for purpose. The greater the genetic difference between two breeds, the greater the hybrid vigour is expected to be in first-generation offspring between those breeds. </p>
<p>Specifically, first-generation offspring are unlikely to develop any recessive disorders that are present in only one of the two parental breeds. On the other hand, they can obviously develop inherited disorders that are present in both parental breeds, which is often the case for disorders such as hip dysplasia. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=487&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=487&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=487&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=612&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=612&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275330/original/file-20190520-69204-1e3ewxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=612&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">Husky dog waiting for his turn to be judged at a dog show in Bishkek, Kyrgyzstan, 05 May 2019. The International Kennel Club Dog Show was held in Bishkek.</span>
<span class="attribution"><span class="source">EPA/IGOR KOVALENKO</span></span>
</figcaption>
</figure>
<p>Importantly, breeding beyond first-generation crosses reduces hybrid vigour and unleashes unpredictable variation. This is good news for traditional stud breeders, because it means the most desirable hybrids are the offspring of two purebreds, rather than those bred subsequently.</p>
<p>Mixed-breed (or “designer”) dogs are not new: the Kennel Club has been <a href="https://www.thekennelclub.org.uk/getting-a-dog-or-puppy/finding-the-right-dog/crossbreed-dogs/">registering them for more than 50 years</a>. Unfortunately, most peer-reviewed studies of canine cross-breeds do not let us estimate actual hybrid vigour, simply because they fail to report the parentage of mixed-breed dogs. </p>
<p>Fortunately, obtaining evidence of actual hybrid vigour in dogs <a href="https://www.ncbi.nlm.nih.gov/pubmed/27387730">should be relatively straightforward</a>: it simply requires veterinary records to include the parentage of mixed-breed dogs, when known. </p>
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Read more:
<a href="https://theconversation.com/are-you-walking-your-dog-enough-100530">Are you walking your dog enough?</a>
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<p>The information being collected by VetCompass and MyBreedData will provide a firm foundation for prioritising research into, and schemes for controlling, inherited disorders within breeds. It also has potential to shed valuable light on the extent to which hybrid vigour exists in dogs. Armed with this information, breeders will be able to combine new technology with the skills of traditional dog breeding to breed dogs that are more likely to look great, be healthy and thrive in the niches we provide for them.</p><img src="https://counter.theconversation.com/content/96635/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul McGreevy consults on a voluntary basis to the RSPCA Australia and is a lifetime member of the RSPCA NSW. He receives funding from the Australian Research Council. In 2017, he received an International Lifetime Achievement Award from the UK Kennel Club.</span></em></p><p class="fine-print"><em><span>Bethany Wilson consults to RSPCA Australia on an ad hoc basis.</span></em></p><p class="fine-print"><em><span>Frank Nicholas 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>A global research effort is targeting inherited disorders in dogs.Paul McGreevy, Professor of Animal Behaviour and Animal Welfare Science, University of SydneyBethany Wilson, Honorary Affiliate, University of SydneyFrank Nicholas, Emeritus Professor of Animal Genetics, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1136412019-03-17T18:48:31Z2019-03-17T18:48:31Z‘Give us a sniff, love’: giving marsupials scents from suitors helps breeding programs<figure><img src="https://images.theconversation.com/files/264062/original/file-20190315-28499-dyfjo3.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A baby eastern barred bandicoot pokes its head out of its mother’s pouch. </span> <span class="attribution"><span class="source">M. Parrott, Zoos Victoria</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Smell is a vital part of sexual attraction for all kinds of animals (including humans). We may be able to use smell to improve breeding programs by giving the female animal a sample sniff of potential mates and letting her choose the best one before introducing them.</p>
<p>Our <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159118305781">new research</a> found female marsupials paired with the male of their choice in captive breeding programs had a higher chance of becoming pregnant, a shorter time to pregnancy and may produce healthier young. </p>
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Read more:
<a href="https://theconversation.com/curious-kids-how-do-we-smell-104772">Curious Kids: How do we smell?</a>
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<h2>Ladies’ choice</h2>
<p>Zoos and breeding institutions traditionally pair animals based on their relatedness and pedigree so they can manage the overall genetic health of the population. It’s expensive and often not possible to transport multiple males just to give a female some options – but if she refuses her solitary suitor when he arrives, it can cause major problems.</p>
<p>Our research shows that presenting the female with a range of scent samples and letting her pick her favourite dramatically increased compatibility. </p>
<p>This simple 10-minute test more than <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159118305781?via%3Dihub">doubled the number of pregnancies</a> and shortened the time to becoming pregnant in a small carnivorous marsupial, the stripe-faced dunnart. </p>
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<a href="https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264063/original/file-20190315-28502-yvjpg7.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>
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<span class="caption">Marissa Parrott with a captive-bred mountain pygmy-possum released to the wild.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<p>Using the same technique in the critically endangered <a href="https://www.zoo.org.au/healesville/animals/mountain-pygmy-possum">mountain pygmy-possum</a> at Healesville Sanctuary, we showed that females had significantly higher breeding success with males they liked during their choice tests. We have shown a similar effect of <a href="http://www.mun.ca/serg/bandicoot-choice.pdf">increasing breeding success and shortening the time to pregnancy</a> in the endangered <a href="https://www.zoo.org.au/werribee/animals/eastern-barred-bandicoot">eastern barred bandicoot</a> at Zoos Victoria through scent and interactions.</p>
<h2>How are female marsupials choosing mates?</h2>
<p>Put simply, they are following their noses. We gave females a choice of male smell and allowed her to sniff out the best mate.</p>
<p>In the first published study of marsupial mate choice, we found female agile antechinus <a href="https://link.springer.com/article/10.1007/s00265-006-0340-8">chose the most genetically suitable male</a> based on his smell. Females preferred males that were genetically dissimilar to themselves (avoiding in-breeding), but not too dissimilar (avoiding genetic out-breeding).</p>
<p>There is a sweet spot to female choice. If you can provide a female with a suite of males, they can choose their most compatible suitor, which in turn is likely to produce the healthiest and fittest young. </p>
<p>Better yet, females are choosing males compared with their own genes, so each female may like a different male, which is good for managing the overall population. However, care must be taken with sisters, as they are likely to have <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159118305781?via%3Dihub">the same choices</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/swingers-hookup-program-can-find-the-right-match-for-endangered-species-68579">Swingers' hookup program can find the right match for endangered species</a>
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<p>This information is particularly helpful for global programs that have endangered species spread across different institutions and zoos, such as <a href="https://www.zoo.org.au/healesville/news/rare-tree-kangaroo-joey-emerges-from-pouch-in-healesville-sanctuary-first">tree kangaroos</a>. </p>
<p>In the dunnarts, we found that freezing and storing the scents of males for up to 40 days <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159118305781?via%3Dihub">did not affect a female’s choice</a> or interest in a scent. Thus, if you have a female tree kangaroo at Melbourne Zoo and are uncertain which male should be sent from overseas, you could freeze scents from eligible bachelors and send them to her in advance for her approval. This could reduce the stress, time and cost associated with sending males between zoos, especially if the male you sent ended up being the wrong choice!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264064/original/file-20190315-28505-1w282ev.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"></a>
<figcaption>
<span class="caption">A stripe-faced dunnart in the captive breeding colony at the University of Melbourne.</span>
<span class="attribution"><span class="source">M Parrott</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>But why focus on females?</h2>
<p>In marsupials, females provide the majority of the care of the young. In the extreme case of the antechinus, all males die after mating, leaving the females with all the work <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0122381">raising the offspring</a>. Thus, females are generally the choosier sex, ensuring they get the maximum benefit from appropriate mate choice.</p>
<p>In other species, such as the critically endangered <a href="https://www.zoo.org.au/werribee/news/plains-wanderer-chicks-born">plains wanderer</a> whose females lay eggs and leave them with stay-at-home fathers, you may expect the male bird’s choice to be more important. He is providing the care to the growing chicks and thus will want to maximise their success through choosing the best mate.</p>
<h2>Can people learn from the marsupial approach?</h2>
<p>Female mate choice is a perennial issue for many humans. A <a href="http://www.coherer.org/pub/mhc.pdf">study that supplied 49 women</a> with T-shirts worn by different men found the women could sniff out the men in their genetic “sweet spot” – not too similar or dissimilar – and found those scents most attractive.</p>
<p>We are not so different to the endangered marsupials we are working to recover. Perhaps in the future, instead of swiping right on an image, we can be sent a palette of smells to choose a potential suitor. Instead of speed dating, could we use smell dating? </p>
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Read more:
<a href="https://theconversation.com/tasmanian-devils-reared-in-captivity-show-they-can-thrive-in-the-wild-68058">Tasmanian devils reared in captivity show they can thrive in the wild</a>
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<p>Certainly, when used in conservation breeding programs, allowing a female to choose her own mate can help find the best pairings, reduce the time to produce young and hopefully help produce the healthiest offspring to fight extinction for their species.</p><img src="https://counter.theconversation.com/content/113641/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marissa Parrott received funding from The Australian Academy of Science and Winifred Violet Scott Charitable Trust for her work with the stripe-faced dunnart. She works for Zoos Victoria, a not-for-profit zoo-based conservation organisation. Zoos Victoria raises funds to aid their work fighting extinction for endangered species, with a commitment that no Victorian terrestrial vertebrate species will ever go extinct on their watch.</span></em></p>Giving female marsupials a sniff of prospective partners increases the chance of a successful love connection.Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/318112014-09-18T15:26:04Z2014-09-18T15:26:04ZStar zoo animals draw crowds but they wont save their species<figure><img src="https://images.theconversation.com/files/59423/original/3w95j98t-1411034231.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A star is born? LuLu and her still unnamed baby.</span> <span class="attribution"><span class="source">Rob Young / Belo Horizonte Zoo</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Brazilians head to the polls in October to decide on their new president. The country’s votes always produce surprises such as the <a href="http://www.reuters.com/article/2010/10/04/us-brazil-election-clown-idUSTRE6930C920101004">election of a clown</a> in 2010 and in 1959 the election of a rhinoceros named <a href="http://content.time.com/time/magazine/article/0,9171,869297,00.html">Cacareco</a> with 100,000 votes as a city councillor of São Paulo. </p>
<p>Cacareco was arguably Brazil’s first celebrity animal but the Belo Horizonte Zoo, through captive breeding, has produced the first two <a href="http://latino.foxnews.com/latino/lifestyle/2014/08/06/brazilian-zoo-welcomes-first-gorilla-born-in-captivity-in-south-america/">“Brazilian” gorillas</a> in the past month. Once their names have been chosen, these baby gorillas will no doubt become celebrities. The zoo just needs to be careful with the naming – after a public competition in the 1970s its first gorilla was called Idi Amin Dada, after the African dictator.</p>
<p>London Zoo’s most famous resident <a href="http://www.nhm.ac.uk/nature-online/collections-at-the-museum/museum-treasures/guy-the-gorilla/index.html">Guy the Gorilla</a> became a national icon in the 60s and 70s; he too was named after an infamous character, 17th century would-be terrorist Guy Fawkes. Superstar zoo animals long pre-date social media and demonstrate that animal celebrity culture is nothing new. </p>
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<img alt="" src="https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/59435/original/xjzzt9t3-1411039671.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">
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<span class="caption">Guy the Gorilla lives on as a statue at London Zoo.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:ZSL_London_-_Guy_the_Gorilla_sculpture_(02).jpg">Katie Chan</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>But modern zoos find it difficult to balance celebs with conservation. Celebrity culture is all about the individual and species conservation is all about the population. Thus, zoos need to strike a happy medium between public (over-)interest in certain star attractions and doing what is right for the whole species.</p>
<p>The problem is it takes a lot of captive animals to save a certain species from extinction, and most zoos are too small to do this by themselves. For large mammals with long lives, for example, we need approximately 250 individuals in captivity to maintain a genetically healthy population. When it comes species’ with shorter generation times (birth to sexual maturity) we need even more individuals in captivity to avoid the loss of <a href="http://press.princeton.edu/chapters/s12_9242.pdf">genetic diversity</a>: so to save a small rodent with a generation interval of a few months we would need thousands of individuals. </p>
<p>Paradoxically it can be more expensive to save a territorial mouse species from extinction than a species of elephant because of the need to construct hundreds, if not thousands, of mouse enclosures.</p>
<p>Genetic diversity is important because it allows species to adapt to their environment. But zoo animals in captivity are not subject to natural selection. Despite this, the goal of many zoos is to create a safety net population of species to guarantee the survival of their wild counterparts; this might be by reintroducing animals to the wild.</p>
<p>Zoos get over the numbers problem by thinking globally. International co-operation means all the gorillas in zoos participating in the captive breeding programme are managed as a <a href="http://www.eaza.net/News/EZE%20Conference/2.%20Additional%20recommended%20reading/Edinburgh2013_TraylorHolzer_CBSG_OnePlanApproach.pdf">metapopulation</a>. That is, although each zoo has its own group of gorillas they are managed as if they are part of a single global population – and issues such as genetic diversity or gender balance are considered in terms of the 850+ in the programme rather than the five or six in any particular zoo.</p>
<p>A studbook keeper uses genetic management software to decide who should breed, who should not breed and who should be paired with who. A digital-age cupid if you like. But here decisions are based on the genetic value of the individual not their celebrity or good looks. The more genetically important the individual, the greater the chance he will be given the nod to breed. Studbook keepers also select against individuals with genetic illnesses.</p>
<p>An individual is genetically important if there are few copies of their genes among others: the aim being to maintain as much genetic diversity in the captive population as possible for as long as possible. This approach has been incredibly successful – the <a href="http://www.iucnredlist.org/details/7961/0">Przewalski horse</a>, for instance, the only surviving breed of truly “wild” (never domesticated, non-feral) horse, was once down to as few as 13 individuals. Thanks to captive breeding it was brought back from the brink of extinction to number in the thousands and is now being reintroduced to Mongolia.</p>
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<img alt="" src="https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/59439/original/58m6zrkn-1411040449.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Back from the near dead.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/File:Takhi_Hustai.jpg">Chinneeb</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Reproductive technologies such as artificial insemination can help with captive breeding, but in general zoos still favour producing offspring the old fashioned way. Mainly because this exposes the animals to less risk; that is, no need for it to participate in an invasive medical procedure. But this does imply that we need to move animals around the world for dating purposes.</p>
<p>Leon, the male gorilla at the Belo Horizonte Zoo, came from Spain – and the two females, Imbi and Loulou came from the UK. These animals are on loan as part of the international gorilla captive breeding programme. Loaning animals across international borders could be a legal nightmare; if there were some sort of dispute in this case – the ownership of the baby gorilla, for instance – which of the three legal systems should be followed in the case of a dispute? </p>
<p>In the spirit of co-operation this problem has been solved in a simple means by zoos through the use of what are essentially gentlemen’s agreements. In this day and age when lawyers seem to run the world it is refreshing to know that trust can win out for species conservation.</p><img src="https://counter.theconversation.com/content/31811/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Young has conducted research with the Belo Horizonte Zoo and aided them in their captive breeding programs.</span></em></p>Brazilians head to the polls in October to decide on their new president. The country’s votes always produce surprises such as the election of a clown in 2010 and in 1959 the election of a rhinoceros named…Robert John Young, Professor of Wildlife Conservation, University of SalfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/287912014-07-11T15:37:32Z2014-07-11T15:37:32ZCaptive breeding could bring big cats back from the brink<p>It may be the fastest animal on earth, but the cheetah is struggling to outrun the threats to its extinction. With only <a href="http://www.iucnredlist.org/details/220/0">50 to 70</a> animals estimated to remain in Iran, the Asiatic cheetah is <a href="http://bigstory.ap.org/article/iran-tries-save-asiatic-cheetah-extinction">on the verge of extinction</a> in the wild. While the more familiar African cheetah is more numerous, with <a href="http://www.iucnredlist.org/details/219/0">around 12,000 individuals</a> across the whole continent, it’s also at risk.</p>
<p>So long as humans and wildlife compete for the use of the same land and resources, there will always be a struggle. This comes down to rights, and which species have more. Animals, including humans, are resource-driven, so removing food sources and fragmenting habitats will have the most serious impact on a species. But when humans go beyond this by actively removing “problem animals”, perhaps due to a perceived threat to crops or livestock, this puts an even greater pressure on their survival.</p>
<p>However, there are means to try to boost cheetah numbers in the wild. Fenced, predator-proof refuge areas, such as private reserves like <a href="http://www.cheetahplains.com/">Cheetah Plains Private Game Reserve</a> and <a href="http://www.timbavati.co.za/">Timbavati Nature Reserve</a>, can be appropriately stocked and managed to ensure cheetah survival. Populations can also be relocated to regions where cheetahs historically ranged but where the cause of their extermination has been addressed. This was demonstrated by the <a href="http://www.cheetah.org">Cheetah Conservation Fund</a> in Namibia and the <a href="http://www.ewt.org.za">Endangered Wildlife Trust</a> in South Africa. </p>
<p>Alternatively, cheetahs can be bred in captivity, trained, and released into controlled wild areas. Where species or sub-species are critically endangered, the release of captive-bred animals into the wild can be used as way of supplementing existing populations or forming new founder populations.</p>
<h2>In training for the wild</h2>
<p>In South Africa, the most promising strategy has been when cheetahs, prior to release, have been “trained to be wild”. This includes changing their diet to the wild game they will encounter on release so they become accustomed to tearing skin and even chewing around bones. And they must develop the strength to be able to bring down prey. It’s also important that these cheetahs become accustomed to starvation periods when prey is scarce or other conditions hinder a successful hunt. These are simple things that a wild cheetah would learn through nurture, but captive breeding does not afford the luxury of learning from mother.</p>
<p>Removing any conditioning or familiarity to human presence that can develop during captivity is also important as this could pose a threat to the cheetahs – and to people. If cheetahs gravitate to human settlements which carry familiar associations with food they are likely to be harmed, and in a volatile situation a cheetah is perfectly capable of causing harm with its teeth and claws.</p>
<p>Once the animal has been released, there are even more decisions to be made about how to monitor and manage the programme. There is debate as to what is deemed a successful re-introduction – for example, if and when breeding can take place, and how independent of human interference the animals really are.</p>
<h2>Difficult but needed</h2>
<p>Such re-introductions <a href="http://upetd.up.ac.za/thesis/available/etd-07042011-101546/">have been tried</a> but have not always been successful, mainly because of human influences like poisoning, hunting, and road accidents. Other deaths have been due to natural problems of starvation, disease, or often due to insufficient conditioning of the animal prior to release.</p>
<p>The forerunner of these style of re-introduction projects is the <a href="http://www.dewildt.co.za">Ann Van Dyke Cheetah Centre</a> (formerly the De Wildt Cheetah and Wildlife Centre), which produced 785 cubs between 1975-2005. As part of a re-introduction project, the centre released six captive bred cheetahs into the wild between 2007-2010 – two single females and two pairs of male <a href="http://www.catcollection.org/cat/cheetah/">coalitions</a> (as social animals, cheetah males often form a group known as a coalition). After extensive training, only one female and two males survived and recovered their wild habits. Since then, there have been no more attempts to re-introduce captive bred cheetah into the wild in South Africa.</p>
<p>Until human populations see evident economic or cultural value in wildlife then protecting endangered species such as the cheetah will continue to be a struggle. And until these values can be assured then any efforts to increase wild cheetah populations will be futile. It’s essential – particularly when dealing with endangered species and predators – that the issues that drove them to become endangered in the first place are tackled.</p>
<p>Unfortunately this usually takes time and effort, and so it’s important to continue working on programmes of captive-born reintroductions. While these have not always been successful, the ground has been laid for future work, and re-introduction remains an important means to win time in the fight against species extinction. </p><img src="https://counter.theconversation.com/content/28791/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nkabeng Maruping-Mzileni 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>It may be the fastest animal on earth, but the cheetah is struggling to outrun the threats to its extinction. With only 50 to 70 animals estimated to remain in Iran, the Asiatic cheetah is on the verge…Nkabeng Maruping-Mzileni, Lecturer in Wildlife Management and Nature Conservation, Tshwane University of TechnologyLicensed as Creative Commons – attribution, no derivatives.