tag:theconversation.com,2011:/fr/topics/vampire-bat-6072/articlesvampire bat – The Conversation2018-10-29T07:49:34Ztag:theconversation.com,2011:article/1049572018-10-29T07:49:34Z2018-10-29T07:49:34ZFive vampire traits that exist in the natural world<figure><img src="https://images.theconversation.com/files/242611/original/file-20181028-169196-122hm3x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The common vampire bat.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/376769800?src=U2Dhk8_ZaR1K48YccSixDg-1-0&size=medium_jpg">Shutterstock</a></span></figcaption></figure><p>When asked to describe a vampire, most people think of a tall, pale creature, with fangs and a cloak. But were the creatures of folklore inspired by real traits seen in the animal kingdom? From avoiding sunlight to using a cloak, here are five classic vampire characteristics that exist in the natural world.</p>
<h2>1. Drinking blood</h2>
<p>The primary characteristic of a vampire is feeding on blood. Although many ectoparasites such as mosquitoes and <a href="https://www.youtube.com/watch?v=oiQ08f6AoqM">leeches also drink blood</a>, the vampire bat is the only species of mammal that is truly haematophagic (feeds exclusively on blood). </p>
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<p><a href="https://www.youtube.com/watch?v=iLp-ls8AoaU">Vampire bats</a> prey on warm-blooded animals such as livestock, locating blood hotspots with their inbuilt infra-red heat sensors, and even utilise a protein called <a href="https://www.ncbi.nlm.nih.gov/pubmed/9795244">“draculin”</a> to keep their prey’s blood flowing.</p>
<p>But they also need to feed every two days in order to survive, and finding prey this frequently is a challenge. Fortunately, vampire bats live in communal roosts, so have evolved a mechanism of <a href="https://news.nationalgeographic.com/2015/11/151117-vampire-bats-blood-food-science-animals/">food sharing</a> whereby they regurgitate blood for starving individuals. This is often done in a tit-for-tat manner – so individuals that have benefited in this way will reciprocate later by donating to the bats that helped them.</p>
<h2>2. Immortality</h2>
<p>Although vampires are often considered immortal, there are few animals that possess the same quality. Animals such as whales and <a href="https://www.theguardian.com/environment/2016/aug/11/400-year-old-greenland-shark-is-the-oldest-vertebrate-animal">sharks can live for over 200 years</a>, and tardigrades (a tiny, water-dwelling creature) can exist in a state of suspended animation indefinitely – coming back to life when hydrated. </p>
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<img alt="" src="https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/242612/original/file-20181028-7059-kqy661.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&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">The immortal jellyfish.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/immortal-jellyfish-turritopsis-nutricula-sarigerme-turkey-646161799?src=A5goKi2Xf9xMj5hBuTPU8w-1-0">Shutterstock</a></span>
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<p>The <a href="https://thebiologist.rsb.org.uk/biologist/158-biologist/features/1510-everlasting-life-the-immortal-jellyfish">immortal jellyfish</a>, however, is reborn repeatedly. Rather like a caterpillar starting life as an egg and developing into a butterfly, the jellyfish begins life as an egg, develops into a larva, grows into a polyp, then buds into a medusa that grows to just 4.5mm when fully mature.</p>
<p>The jellyfish is “immortal” because it can change from a medusa back into a polyp when stressed. This “transdifferentiation” – reverting back to a previous form then redeveloping into the latter form – could aid our understanding of <a href="https://singularityhub.com/2011/04/25/immortal-jellyfish-provides-clues-for-regenerative-medicine/#sm.000dzk9t91awufhzyj41dybsrlkxe">repairing and regenerating damaged tissues</a>.</p>
<p>Although most medusae succumb to predation or disease eventually, this jellyfish has the potential to regenerate indefinitely, making it pretty much immortal.</p>
<h2>3. Avoiding sunlight</h2>
<p>Like many vampires, animals often avoid light. These tend to include invertebrates that prefer to inhabit dark conditions, or nocturnal species that are adapted to feeding at night. Nevertheless, there are a few species that are hypersensitive to light and actively avoid it at all costs, including some <a href="https://theconversation.com/there-be-dragons-creatures-you-might-find-on-a-real-journey-to-the-centre-of-the-earth-57905">cave dwellers</a> that spend their lives in permanent darkness.</p>
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<p>Perhaps one of the strangest-looking creatures is the <a href="https://www.youtube.com/watch?v=A5DcOEzW1wA">naked mole rat</a>, which inhabits underground burrows in Africa. Like vampires, they are pale, avoid sunlight and are known for their longevity. They also possess a colonial lifestyle, similar to ants and bees – workers acquire food, maintain the tunnel system and protect the nest of the breeding queen, akin to a vampire sire.</p>
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<span class="caption">The naked mole rat.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/naked-molerat-guarding-underground-tunnel-heterocephalus-1015648228?src=T6hvdLTTxLT70LfLMytYmA-1-14">Shutterstock</a></span>
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<h2>4. Heightened senses</h2>
<p>Vampires are often depicted with heightened senses such as vision and hearing. But many animals have also evolved <a href="https://theconversation.com/five-comic-book-superpowers-that-really-exist-in-animals-81352">super senses</a> far exceeding those of both humans and vampires.</p>
<p>Vampires, for example, seem to have a particularly keen sense of smell. This characteristic is mirrored in animals such as bears, which can <a href="https://www.researchgate.net/profile/Ramesh_Padodara/publication/262932824_Olfactory_Sense_in_Different_Animals/links/02e7e53958d94f129c000000/Olfactory-Sense-in-Different-Animals.pdf">smell food from up to 18 miles away</a>.</p>
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<img alt="" src="https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/242614/original/file-20181028-7044-1k4a27u.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">Sharks have a directional sense of smell.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTU0MDc3MTk2NCwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfNjg3MDk4MDMyIiwiayI6InBob3RvLzY4NzA5ODAzMi9tZWRpdW0uanBnIiwibSI6MSwiZCI6InNodXR0ZXJzdG9jay1tZWRpYSJ9LCJRdG93UzVia1pOWFpPbGtVK0xKQStuS0ZZL00iXQ%2Fshutterstock_687098032.jpg&pi=33421636&m=687098032&src=mjCOakJjF9-oRsl7NjNkbw-1-24">Shutterstock</a></span>
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<p>Although it is often stated that sharks can smell a single drop of blood from a mile away, this is an <a href="https://www.ripleys.com/weird-news/sharks-smell-blood/">exaggeration</a> – it is more like a single drop in a swimming pool. Nevertheless, sharks have nostrils that give them a directional sense of smell, allowing them to pin-point prey with incredible accuracy. Their nostrils also have only one function: to detect odours. Perhaps undead vampires have such an impressive sense of smell because they don’t have to breathe either. </p>
<h2>5. Morphing</h2>
<p>Vampires can also morph into another form, such as a bat, often behind the shroud of a cloak. Species such as the mimic octopus are similarly capable of <a href="https://theconversation.com/some-shape-shifting-animals-that-can-morph-to-fool-others-39616">changing shape</a> to avoid a tricky situation. Unfortunately, they can’t turn into a bat and fly away, but this is essentially what a caterpillar does when it morphs into a butterfly and flutters skywards – although this process takes them weeks rather than an instant. </p>
<p>Like vampires that disappear in a puff of smoke, squid are also capable of producing <a href="https://www.theguardian.com/science/2017/aug/09/why-do-cephalopods-produce-ink-and-what-on-earth-is-it-anyway">clouds of ink</a> – confusing predators and creating the illusion that they have vanished.</p>
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<p>But what about the cloak? Nothing resembles a textbook vampire quite like the black heron. These birds <a href="https://www.youtube.com/watch?v=gepRyOILsxE">create a cloak</a> of plumage around themselves, forming a shadow that both enables the birds to see prey in the water, and creates a dark trap that fish dart into, assuming it’s cover.</p>
<p>There are many animals that possess vampiric qualities, so it is likely that stories of vampires or mythical blood suckers, such as the <a href="http://www.bbc.com/earth/story/20161109-the-truth-about-a-strange-blood-sucking-monster">chupacabra</a>, are based, in part, on these characteristics. </p>
<p>And they all have one more thing in common, too: all can be killed with a stake through the heart.</p><img src="https://counter.theconversation.com/content/104957/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Gentle works for Nottingham Trent University</span></em></p>From naked mole rats to the immortal jellyfish – the creatures that would make Dracula shudder.Louise Gentle, Senior Lecturer in Behavioural Ecology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/716542017-02-15T07:32:41Z2017-02-15T07:32:41ZHow we discovered the vampire bats that have learned to drink human blood<figure><img src="https://images.theconversation.com/files/156524/original/image-20170213-23337-1rwmb0o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Doesn't look like much of a threat, does he?</span> <span class="attribution"><a class="source" href="https://goo.gl/images/oQIg5L">Gerry Carter/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>What’s for dinner? For some Brazilian vampire bats, these days it’s human blood.</p>
<p>That’s the surprising outcome of my research, recently published in the <a href="http://www.bioone.org/toc/acta/18/2">Acta Chiropterologica</a> journal, which revealed that the hairy-legged vampire bat of Pernambuco, Brazil, has developed an appetite for human blood over that of other possible prey. </p>
<p>This finding upends all the existing scientific literature on this bat species, which typically feeds on bird blood. </p>
<h2>A little-known bat (with a secret)</h2>
<p>The hairy-legged vampire bat (<em>Diphylla ecaudata</em>) is the least-studied of the <a href="https://en.wikipedia.org/wiki/Vampire_bat">three species of known vampire bats</a>. In 20 years working as a zoologist, I had never held a live specimen in my hands.</p>
<p>But there I was in Pernambuco’s drylands in 2013, inside a cave in the Catimbau National Park, when I focused the flashlight on a little colony of bats above my head and spotted a few <em>Diphylla</em>. </p>
<p>Though not the prettiest species of bat, they are more delicate than some, with a gentle face, small ears and, I must say, a soft look. </p>
<p>On the ground below the bats, I saw pools of guano, or bat droppings, each the size of a soup dish. Vampire bats are hematophagous, meaning they can only eat blood, so their excrement is tinged red. </p>
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<img alt="" src="https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/156676/original/image-20170213-25962-1lafbgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&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">View of Catimbau National Park, where some bats are starting to change their feeding habits.</span>
<span class="attribution"><span class="source">Enrico Bernard/UFPE</span>, <span class="license">Author provided</span></span>
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<p><em>Diphylla</em> prey on bird blood, but in Catimbau Park, native birds of medium and large size have <a href="http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492005001400001">become locally extinct</a>. Probably due to <a href="http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492005001400001">unregulated hunting</a>, the white-browed guan, the yellow-legged tinamou, and the picazuro pigeon — all potential prey for <em>Diphylla</em> in the past — were no longer observed there by 2013. </p>
<p>So what were those <em>Diphylla</em> feeding on, if not birds? Goat blood might make sense. I had seen many grazing in the park, raised by the hundreds of families who still live in Catimbau, despite its legal status as a natural protection zone. </p>
<p>I returned to the Federal University of Pernambuco in Recife, determined to investigate <em>Diphylla’_s</em>_ diet.</p>
<h2>The scientific method</h2>
<p>Extracting DNA from vampire-bat guano is no small feat. Proteins in their digestive tracts can break down the DNA of the blood consumed, and samples collected in caves can be contaminated with exogenous DNA, either from other organisms in the guano (such as bacteria, fungi and insects) or by the sample collector. </p>
<p>For this task I joined forces with Fernanda Ito, then an UFPE student working toward her undergraduate honours thesis. She liked the idea of using fecal DNA to figure out the bats’ prey as her thesis project. Later our team welcomed Rodrigo Torres, from UFPE’s Department of Zoology, who works with genetics applied to biodiversity conservation.</p>
<p>If all went well, the sequences we obtained would be compared to those deposited in GenBank, indicating the possible prey <em>Diphylla</em> were feeding on. </p>
<p>The process of extracting and purifying the DNA was as long and dramatic as a Brazilian soap opera. For days, Fernanda persistently tested and modified protocols at various temperatures and lengths of time, until finding the right combination that would allow the perfect reaction to happen. </p>
<p>Finally, when Fernanda was on the verge of quitting in frustration, she managed to sequence the samples. When we compared our bat DNA sequences with those obtained from goats, pigs, cows, dogs, chickens and humans, we found that <em>Diphylla</em> had consumed blood from chickens and humans.</p>
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<img alt="" src="https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/156675/original/image-20170213-25969-1vlmvj6.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">
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<span class="caption">Researcher installing monitoring equipment in a cave in Brazil’s Catimbau National Park.</span>
<span class="attribution"><span class="source">Eder Barbier</span>, <span class="license">Author provided</span></span>
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<p>At least three samples obtained on different dates pointed to the consumption of human blood. The other 12 of our 15 samples found evidence of <em>Diphylla</em> sucking chickens’ blood.</p>
<p>This was an intriguing finding. Science suggests that <em>Diphylla</em> would never consume human blood. Indeed, three articles (from Mexico in <a href="https://academic.oup.com/jmammal/article-abstract/48/4/683/861258/Villa-R-Bernardo-Los-Murcielagos-de-Mexico-Su?redirectedFrom=fulltext">1966</a> and <a href="https://academic.oup.com/jmammal/article-abstract/62/1/215/953100/Observations-on-Diphylla-ecaudata-in-Captivity?redirectedFrom=fulltext">1981</a> and from Brazil in <a href="http://www.bibliotecadigital.unicamp.br/document/?code=vtls000075144">1994</a>) even indicated that in captivity, <em>Diphylla</em> would rather starve to death than feed on blood from cows, rats, rabbits, pigs or live goats. </p>
<h2>Groundbreaking data</h2>
<p>Our data was contrary to all the information available on <em>Diphylla</em> so far. In fact, we had seen <a href="https://books.google.com.mx/books/about/Comparative_Nutritional_Ecology_of_Two_G.html?id=1H5PAAAAYAAJ&redir_esc=y">reports</a> that indicated that this species actually has a physiological intolerance of mammalian blood, which has more dry matter, mainly proteins, than bird blood (which contains more water and fat).</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=348&fit=crop&dpr=1 600w, https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=348&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=348&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=437&fit=crop&dpr=1 754w, https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=437&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/156677/original/image-20170213-25977-bufyup.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=437&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Diphylla</em> ecaudata.</span>
<span class="attribution"><span class="source">Eder Barbier</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>That would explain why the bats weren’t going after the goats, as I had originally thought. But how to explain the strange preference for human blood? </p>
<p>It seems the scarcity of native large bird species in the park has led <em>Diphylla</em> to develop a more flexible diet than scientists could have imagined. That may be good for <em>Diphylla’s</em> survival, but it’s also an indicator that the area we studied is not faring well. In northeastern Brazil’s dry forests, native species are disappearing, presumably forcing other species, too, to change their diet and behaviour. </p>
<p>The presence of human blood in bat guano also raises public health issues. Clearly, some people in the Catimbau region are being bitten by bats, raising the risk that rabies and other diseases could be transmitted. </p>
<p>On the positive side, Fernanda defended her thesis with success and our article in Acta Chiropterologica is attracting media coverage worldwide. </p>
<p>Discovering that bats can learn to live on human blood has given me several new ideas to explore, such as radio-tracking them to find their human prey. </p>
<p>New research will start soon. Now, I just have to find a new Fernanda …</p><img src="https://counter.theconversation.com/content/71654/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Enrico Bernard receives funding from Brazilian CNPq and FACEPE. </span></em></p>New data shows that the hairy-legged vampire bat of Pernambuco, Brazil, has developed an appetite for human blood over that of other possible prey.Enrico Bernard, Departamento de Zoologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco (UFPE)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/606032016-06-08T05:35:01Z2016-06-08T05:35:01ZHow to stop vampire bats wreaking havoc (no stakes or garlic required)<figure><img src="https://images.theconversation.com/files/125571/original/image-20160607-15049-6lhmjk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Daniel Streicker/Julio Benavides</span></span></figcaption></figure><p>During the darkest hours of the night, they fly and hunt for prey. They live in caves and ruined buildings and have to drink blood every night to survive. They can bite with their fangs without you even noticing. No wonder these bats are called vampires. Yet when it comes to coping with these bloodthirsty creatures, the good news is that a breakthrough could finally be in sight. </p>
<p>Vampire bats only live in one part of the world – which is a relief, unless you happen to be in Latin America. They exist between northern Mexico and northern Chile, and they are a major problem. They are now the <a href="http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1020-49892009000300010">main cause</a> of human deaths from rabies in the region. </p>
<p>Between 2009 and 2013, vampire bats bit 20,000 people in Peru alone, according to the country’s health minister; and in communities across the Amazon, where bites are commonplace, the rate of rabies infection <a href="http://www.ncbi.nlm.nih.gov/pubmed/9025698">could be</a> almost as high as 1% per year. At least 12 children were killed by rabies earlier <a href="http://www.dailymail.co.uk/news/article-3440814/Rabies-spread-bats-kills-12-Peruvian-Amazon.html">this year</a> in a single outbreak. </p>
<p>Meanwhile, <a href="http://www.sciencedirect.com/science/article/pii/S0168170205000705">farmers lose</a> a few thousand livestock every year – or perhaps many more, since the worst-hit remote communities almost certainly under-report infection rates. We found that about 70% of farms in the Andes have at least one animal bitten regularly. </p>
<p>The virus is also steadily expanding into areas that were historically free of the disease, as we discovered through our <a href="http://rspb.royalsocietypublishing.org/content/283/1832/20160328">recent work</a> in Peru. As many as 12 new governmental districts become infected per year on average, which has doubled the number of outbreaks at national level. We found that the virus invades new areas in waves that advance at between 10km and 20km per year. The advance is stalled only by tall mountains that rise above the altitudes where bats thrive. </p>
<p>We don’t know what has sparked the spread of rabies into new territories, but one possibility is that bats nowadays have access to more livestock and man-made structures for roosting. This could be making it possible to allow the disease to spread by connecting previously isolated populations. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/125515/original/image-20160607-15031-1d2fdds.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">Vampire bats have sharp teeth for feeding on blood.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&searchterm=vampire%20bats&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=376769797">Wikimedia</a></span>
</figcaption>
</figure>
<h2>Breaking the waves</h2>
<p>We are pleased to report that the waves of rabies in bats move quite predictably. This makes it possible to forecast in some areas when and where the virus is likely to strike next. With this information, which has not been known until now, the authorities in Peru will have the option of anticipating their arrival, allowing them to vaccinate the animals and people before deaths begin. </p>
<p>This would be a big shift from the norm, where livestock and people typically get vaccinated only after an outbreak has been declared. Assuming the virus behaves in the same way in other countries, the same approach could be adopted across Latin America. </p>
<p>Having said that, vaccinating animals and people does nothing to prevent the spread of the virus. It only saves the recipients of vaccines from dying. If you want to stop the virus, you have to tackle the source of the transmission – the bats themselves. </p>
<p>Since the 1970s, Latin American governments’ answer has been bat culls. Yet there is no <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1439-0450.2003.00713.x/full">convincing evidence</a> that this has made a substantial difference, and it may even have been counterproductive – by <a href="http://rspb.royalsocietypublishing.org/content/early/2012/06/07/rspb.2012.0538.short">mainly targetting</a> adult bats that are already immune and <a href="http://www.pnas.org/content/110/51/20837.abstract">provoking bats</a> to disperse between roosts, it might have hastened the spread of the disease. </p>
<p>Governments across the world have been <a href="http://www.ncbi.nlm.nih.gov/pubmed/15742629">very successful</a> at using mass-vaccination programmes to curb rabies in dogs and other key carrier species such as foxes and raccoons, but this has never been attempted on a large scale with vampire bats. This is despite the fact that an effective vaccine is now an option. Researchers in <a href="http://www.ncbi.nlm.nih.gov/pubmed/9682368">Mexico</a> and <a href="http://www.ncbi.nlm.nih.gov/pubmed/18761044">Brazil</a> have shown that you can prevent bats in captivity from catching rabies by giving them an orally transmitted gel that has been impregnated with the vaccine. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/125570/original/image-20160607-7438-1g0bp43.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rabies spreads among bats by bites.</span>
<span class="attribution"><span class="source">Daniel Streicker</span></span>
</figcaption>
</figure>
<p>Whether this would work with wild bats is another matter, of course. All the biological and ethical challenges inherent in any wildlife vaccination campaign are likely to apply, not to mention the logistical challenge of remote landscapes in the Andes and Amazon. </p>
<p>But our findings on the way that the disease spreads in waves among bats could change the game here, too: rather than seeking to eliminate rabies from all vampire bats in endemically infected areas, we could try to halt the spread into new areas instead. </p>
<p>It is also important to galvanise interest in bat vaccination among public health officials and conservationists for other reasons. As well as rabies, bat populations are thought to spread other diseases such as <a href="http://www.who.int/mediacentre/factsheets/fs103/en/">Ebola</a> and <a href="http://www.batcon.org/index.php/our-work/regions/usa-canada/address-serious-threats/wns-intro">white-nose syndrome</a> in other parts of the world. </p>
<p>Given that vampire bat rabies has a major impact on human lives and livestock, and we now have both an effective vaccine and a better understanding of how it spreads, we believe this is the right starting point to inspire a new generation of disease control strategies for bats. It is surely something we could all get our teeth into.</p><img src="https://counter.theconversation.com/content/60603/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julio Benavides receives funding from The UK – Peru CONCYTEC Fund for Science and Innovation. He is the vice-president of the not-for-profit group Apes Incorporated.</span></em></p><p class="fine-print"><em><span>Daniel Streicker receives funding from the Wellcome Trust, the Royal Society, the Beit Trust, National Geographic, the UK-Peru CONCYTEC Fund for Science and Innovation and the Leverhulme Trust</span></em></p>They kill thousands of animals and people every year by spreading rabies. New research findings could solve the problem.Julio Benavides, Research Associate, University of GlasgowDaniel Streicker, Research Fellow, University of GlasgowLicensed as Creative Commons – attribution, no derivatives.