tag:theconversation.com,2011:/fr/topics/venomous-snakes-32239/articlesVenomous snakes – The Conversation2023-10-05T15:49:43Ztag:theconversation.com,2011:article/2132942023-10-05T15:49:43Z2023-10-05T15:49:43ZFossil snake traces: another world-first find on South Africa’s Cape south coast<figure><img src="https://images.theconversation.com/files/550184/original/file-20230926-29-aodxzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Puff adders leave linear, sometimes slightly undulating traces.</span> <span class="attribution"><span class="source">EcoPrint/Shutterstock</span></span></figcaption></figure><p>Snakes are familiar, distinctive – and often feared – reptiles. And they’ve been around for a long time: body fossils found in the UK, Portugal and the US stretch all the way back to <a href="https://doi.org/10.1038/ncomms6996">the late Jurassic period</a>, about 150 million years ago.</p>
<p>Until now, though, there hasn’t been a single description of a surface fossilised snake trace – a mark on a surface that’s become cemented and re-exposed over time – anywhere in the world. </p>
<p>There are probably several reasons for this. One is that the tracks of large quadrupeds (four-legged animals), including dinosaurs, are easier to recognise than those of snakes. Another reason could be that snakes tend to avoid sandy or muddy areas in which their trails could be registered, preferring vegetated terrain. Maybe, as the weight of the snake is distributed over its entire length, the trails are shallow and are not easy to identify. </p>
<p>Or perhaps researchers are not adequately familiar with the types of traces that snakes can create. </p>
<p>We are part of an <a href="https://theconversation.com/my-job-is-full-of-fossilised-poop-but-theres-nothing-icky-about-ichnology-182906">ichnological team</a> – experts in identifying fossil tracks and traces. In a <a href="https://www.tandfonline.com/doi/abs/10.1080/10420940.2023.2250062?src=">recently published article</a> in the journal <em>Ichnos</em>, we described the first snake trace in the fossil record, which we found on South Africa’s Cape south coast. It dates to the <a href="https://www.britannica.com/science/Pleistocene-Epoch">Pleistocene epoch</a>, and our studies have shown that it was probably made between 93,000 and 83,000 years ago, almost certainly by a puff adder (<em>Bitis arietans</em>).</p>
<p>As this is a world first, our research team was obliged to create a new ichnogenus and ichnospecies, <em>Anguinichnus linearis</em>, to describe the distinctive pattern in the sand registered by the puff adder. </p>
<h2>A snake and a buffalo</h2>
<p>The puff adder is a not uncommon sight on the Cape south coast today and, with good reason, strikes fear into residents and visitors: its cytotoxic (tissue-destroying) venom can cause the loss of a limb or worse. It habitually suns itself on trails, staying motionless, and then strikes without warning.</p>
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Read more:
<a href="https://theconversation.com/the-ultimate-in-stealth-puff-adders-employ-camouflage-at-every-level-53316">The ultimate in stealth, puff adders employ camouflage at every level</a>
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<p>We found the trace fossil in the <a href="https://www.capenature.co.za/reserves/walker-bay-nature-reserve">Walker Bay Nature Reserve</a> (adjacent to <a href="https://www.grootbos.com/en">Grootbos Private Nature Reserve</a>), just over 100 kilometres south-east of Cape Town. </p>
<p>Intriguingly, a <a href="https://prehistoric-fauna.com/Pelorovis-antiquus">long-horned buffalo</a> – an extinct species – had walked across the same dune surface soon after the snake left its trace. We know this because one of the buffalo’s tracks is superimposed on the puff adder trace, slightly deforming it.</p>
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<img alt="A large, smooth, light grey rock surface on which the indent of a slithering snake is visible, as are several hoof prints" src="https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551116/original/file-20230929-21-r9kbpi.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">The puff adder trail, crossed by a long-horned buffalo trackway. Geological hammer for scale.</span>
<span class="attribution"><span class="source">Hayley Cawthra</span></span>
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<p>The puff adder and long-horned buffalo traces were found on the surface of a loose slab, 3 metres long and 2.6 metres wide, which had become dislodged and fallen down onto the beach from overlying cliffs. The slab is submerged twice a day by high tides. We were fortunate to discover it when its surface was bare, as repeat visits have shown that it is often covered in algae or by a thick layer of beach sand.</p>
<h2>Snakes in motion</h2>
<p>Snakes use four main types of locomotion. Each results in distinctive, recognisable traces. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/7-AKPFiIEEw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Here’s how snakes move through the world.</span></figcaption>
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<p>Puff adders are heavy, thick-set snakes with an average adult length of less than a metre. They mostly employ rectilinear motion, leaving a linear, sometimes slightly undulating trace, often with a central drag mark registered by the tail tip. In this form of motion the snake uses its weight and its belly muscles and grips rough areas on the surface with the posterior edges of its scales. It is drawn forwards through the muscular contractions, creating a linear trace. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/iWZfIzIayDk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A puff adder in motion, filmed by research team member Mark Dixon.</span></figcaption>
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<p>We also found possible trace evidence at other sites on the Cape south coast of sidewinding and undulatory motion, but this was inconclusive. We will be looking for further, more conclusive evidence. </p>
<h2>Filling important gaps</h2>
<p>The newly described puff adder traces help fill a gap in the Pleistocene trace fossil record from the region. <a href="https://doi.org/10.1016/j.quascirev.2019.07.039">More than 350 vertebrate tracksites</a> have been identified, of mammals, birds and reptiles. Most of these sites were registered on dune surfaces, which have now become <a href="https://doi.org/10.1016/S0012-8252(01)00054-X">cemented into aeolianites and re-exposed</a>. Our latest find is yet another global first for the Cape south coast. </p>
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Read more:
<a href="https://theconversation.com/first-fossil-trails-of-baby-sea-turtles-found-in-south-africa-122434">First fossil trails of baby sea turtles found in South Africa</a>
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<p>With other vertebrate groups, such as dinosaurs and crocodiles, the trace fossil record has substantially augmented the body fossil record, providing new insights. Hopefully this discovery will act as a spur to identify other snake traces from around the world from older deposits, and thus increase our understanding of the evolution of snakes and help to fill a substantial gap in the global trace fossil record.</p><img src="https://counter.theconversation.com/content/213294/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The trace was probably made between 93,000 and 83,000 years ago, almost certainly by a puff adder.Charles Helm, Research Associate, African Centre for Coastal Palaeoscience, Nelson Mandela UniversityHayley Cawthra, Specialist Scientist, Council for GeoscienceLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1751882022-02-06T19:06:41Z2022-02-06T19:06:41Z7 reasons Australia is the lucky country when it comes to snakes<figure><img src="https://images.theconversation.com/files/444632/original/file-20220206-23-1lf3f24.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2038%2C1321&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A dugite (Pseudonaja affinis) </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/96574168@N02/">Chris Hay</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Australia has a global reputation as a land full of danger, where seemingly everything is out to kill you. Crocodiles lurk in estuaries, large spiders hide in bathrooms, and we share our suburbs with some of the world’s most venomous snakes.</p>
<p>Snakes hold a particular fear and fascination for many people. The bite of an <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0053188">eastern brown snake</a> can kill an adult in under an hour. And that’s just one of more than <a href="https://reptile-database.reptarium.cz/advanced_search?taxon=Elapidae&location=Australia&submit=Search">150 venomous snakes</a> inhabiting the island continent across land and sea. Australian snakes are well and truly <a href="https://www.sciencedirect.com/science/article/abs/pii/0041010179902459">overrepresented</a> out of the world’s top 25 most venomous snakes. </p>
<p>Terrifying, right? Not quite. Australians are actually extremely lucky when it comes to snakes. Here are seven reasons why. </p>
<h2>1) Our snakes bolt away from us</h2>
<p>The best way to <a href="https://www.abc.net.au/news/science/2021-10-30/snakes-venomous-how-to-survive-a-bite/100406488">survive a snakebite</a> is of course not to be bitten. Keeping your distance is the easiest way to avoid a bite. </p>
<p>But what if you’re walking through the bush and don’t see the snake? Luckily, most Australian snakes will rapidly <a href="https://www.publish.csiro.au/WR/WR98042">slither away</a> from us. </p>
<p>It could be much worse. Imagine if most of our snakes were like vipers or rattlesnakes, which hold their ground and can be easily trodden on. And imagine if our venomous snakes could sense our body heat, as pit vipers and rattlesnakes do with their heat-sensing pits. For Australians, simply staying still can keep you safe.</p>
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<a href="https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A blue pit viper from Komodo Island flicks its tongue upwards" src="https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443274/original/file-20220130-17-4jsreu.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">Pit vipers like this white-lipped pit viper (<em>Trimeresurus insularis</em>) from Indonesia can sense heat but can’t bolt away.</span>
<span class="attribution"><span class="source">Christina N. Zdenek</span></span>
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<h2>2) We have very few snakebite deaths</h2>
<p>Compared to other countries with many snake species, Australia has orders of magnitude fewer <a href="http://www.ncbi.nlm.nih.gov/pubmed/28905944">snakebites and related deaths</a>. South Africa has <a href="https://doi.org/10.1016/j.toxicon.2018.12.002">476 snakebite deaths</a> on average every year. By contrast, Australia has <a href="https://onlinelibrary.wiley.com/doi/10.1111/imj.13297">two or three</a>.</p>
<h2>3) If you do get bitten, you’re very unlikely to lose a limb</h2>
<p>Most snakebites in Australia are completely painless. This is in part due to the short fangs of our brown snakes (<em>Pseudonaja</em> spp.), who are responsible for <a href="https://pubmed.ncbi.nlm.nih.gov/19570990/">most bites in Australia</a>, but mainly because most Australian snakes have venom which <a href="http://dx.doi.org/10.1580/0953-9859-2.3.219">works internally</a>, rather than locally at the bite site. This means snakebites in Australia very rarely result in amputations. </p>
<p>By contrast, across sub-Saharan Africa it is <a href="http://dx.doi.org/10.1016/j.toxicon.2010.12.022">sadly common</a>, with almost <a href="https://doi.org/10.1016/j.toxicon.2018.12.002">2400 amputations</a> reported in Africa’s most populous country, Nigeria, every year. Unfortunately, the people <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0000569">most at risk of snakebite</a> are the ones least able to afford the high treatment costs.</p>
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<a href="https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Dugite's fangs" src="https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443255/original/file-20220129-15-1orl5i8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&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">Brown snakes like this dugite (<em>Pseudonaja affinis</em>) have small fangs.</span>
<span class="attribution"><span class="source">Christina N. Zdenek & Chris Hay</span></span>
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<h2>4) We have great access to excellent antivenom and other treatments</h2>
<p>For snakebites, antivenom is the only <a href="https://pubmed.ncbi.nlm.nih.gov/29746978/">specific treatment</a>. If you’re unlucky enough to be bitten by a highly venomous snake, getting the antivenom as quickly as possible is vital. Luckily, antivenoms work quickly, and ours are high quality. </p>
<p>Antivenom is often produced from purified horse antibodies. It’s well known antivenom can cause anaphylaxis, which occurs <a href="https://pubmed.ncbi.nlm.nih.gov/18429716">around 10%</a> of the time in Australia. These reactions can be quickly reversed by adrenaline administered in a hospital. </p>
<p>By contrast, some other countries have <a href="https://theconversation.com/unsuitable-antivenoms-are-being-sold-in-africa-costing-lives-83658">alarmingly ineffective antivenoms</a> as well as <a href="https://doi.org/10.1016/j.toxicon.2020.12.009">triggering anaphylaxis</a> 57% of the time. </p>
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Read more:
<a href="https://theconversation.com/does-australia-really-have-the-deadliest-snakes-we-debunk-6-common-myths-145765">Does Australia really have the deadliest snakes? We debunk 6 common myths</a>
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<p>You can get antivenom at 750 hospitals across Australia. For more remote regions, snakebite victims benefit from <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(79)90580-4/fulltext?cc=y">proven pressure-immobilisation </a> which should be applied before the Royal Flying Doctors come to the rescue. </p>
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<a href="https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seven Australian snake antivenoms." src="https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=398&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=398&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443306/original/file-20220131-15-1r8713j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=398&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">Many quality snake antivenoms are available in Australia.</span>
<span class="attribution"><span class="source">Christina N. Zdenek</span></span>
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<h2>5) We have the world’s only snake venom detection kits</h2>
<p>Using the wrong antivenom can lead to the treatment failing. So how do doctors know which antivenom to administer? It’s not via snake identification by the victim because, more often than not, Australians <a href="https://www.tandfonline.com/doi/abs/10.1080/10871209.2020.1769778?journalCode=uhdw20">get it wrong</a>. </p>
<p>In 1979, Australia became the <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2021.661457/full">first country in the world</a> to have a commercial snake venom detection kit to make antivenom choice more accurate. Even now, we’re the only ones with this option. </p>
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Read more:
<a href="https://theconversation.com/the-suns-shining-and-snakes-are-emerging-but-theyre-not-out-to-get-you-heres-what-theyre-really-up-to-168089">The sun's shining and snakes are emerging, but they're not out to get you. Here's what they're really up to</a>
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<p>Every other country has to rely on more dangerous options. Either the victim brings the snake to hospital for a professional ID, or doctors have to <a href="https://www.ajol.info/index.php/safp/article/view/13271">rely on the patient’s symptoms</a> and location where they were bitten to take an educated guess as to which antivenom will work. </p>
<p>As you’d expect, this can be a challenge. Why? Because there can be a great deal of <a href="https://pubmed.ncbi.nlm.nih.gov/33153179/">overlap of symptoms</a> caused by venom from unrelated species. Plus, picking the species responsible can take years of experience treating snakebite which many doctors do not have. </p>
<p>In Australia, there’s another option if the kit is unavailable: <a href="https://www.nps.org.au/medicine-finder/polyvalent-snake-antivenom-concentrate-for-infusion">polyvalent antivenom</a>, effective against all our most dangerous snakes. </p>
<h2>6) Snakebites are covered by Medicare</h2>
<p>Antivenom can be <a href="https://www.sciencedirect.com/science/article/abs/pii/S0887233318304399?via%3Dihub">prohibitively expensive</a>, costing thousands of dollars per dose. </p>
<p>Our nearest neighbour, Papua New Guinea, is a snakebite hotspot. But many people simply do not have the money to pay for the antivenom. In some areas, taipans kill <a href="https://www.abc.net.au/news/2013-04-03/an-png-trials-new-snake-anti-venom/4606988">more people than malaria</a> due to the cost of treatment. </p>
<p>In Australia, treatment for a bite may cost around AUD$6,000, but this cost is covered by Medicare. In my lab, we’re working to make snakebite treatment more affordable by testing <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2021.688802/full">next-generation snakebite treatments</a>. </p>
<h2>7) Snake venom is actually saving lives</h2>
<p>To top it all off, snake venom is saving lives. There are <a href="https://www.mdpi.com/2072-6651/11/10/564">six therapeutic drugs</a> on the global market derived from snake venoms, with another two in clinical trials. </p>
<p>Our many venomous snake species hold in their venom glands a mini drug library, a cornucopia for scientists to trawl through looking for promising new therapeutic drugs. In fact, a toxin from the venom of <a href="http://dx.doi.org/10.1038/s41467-017-00647-9">eastern brown snakes</a> (<em>P. textilis</em>) is <a href="https://www.varmx.com/news/first-subjects-dosed-first-human-trial-varmxs-anticoagulant-reversal-agent-vmx-c001-0">being tested</a> as a drug used to reverse life-threatening bleeding complications.</p>
<p>Rather than fearing our venomous snakes, let’s try seeing them as they are. </p>
<p>They pose little risk to us. They flee from us. Their bites can usually be cured quickly. Their venom holds therapeutic promise. And they play a <a href="https://www.publish.csiro.au/wr/wr00106">vital role</a> in keeping down the numbers of introduced rats and mice. </p>
<p>So let’s take a moment to appreciate Australia’s wealth of beautiful snakes.</p><img src="https://counter.theconversation.com/content/175188/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christina N. Zdenek 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>Over 150 types of venomous snake live in Australia. But deaths from snakebite are vanishingly rare. From snake behaviour to human innovation, here are the reasons why.Christina N. Zdenek, Lab Manager/Post-doc at the Venom Evolution Lab, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1680892021-09-23T20:04:15Z2021-09-23T20:04:15ZThe sun’s shining and snakes are emerging, but they’re not out to get you. Here’s what they’re really up to<figure><img src="https://images.theconversation.com/files/422809/original/file-20210923-15-yxnhp7.jpg?ixlib=rb-1.1.0&rect=0%2C14%2C4914%2C3057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>It’s early spring in southern Australia and the sun is, gloriously, out. You decide to head to your local patch of greenery – by the creek, lake, or foreshore – with the sun on your face, the breeze in your hair, and your dog’s tongue blissfully lolling. </p>
<p>Suddenly you see it. Paused on the path just a few meters in front of your feet, soaking up those same springtime rays — a snake.</p>
<p>Love them or loathe them, snakes have been co-existing with, and haunting us, since well before our ancestors called themselves “human”. From the <a href="https://www.biblegateway.com/verse/en/Genesis%203%3A1">subtle tempter of Genesis</a> to the <a href="https://www.worldhistory.org/Quetzalcoatl/">feathered serpent deities of Mesoamerica</a>, snakes have always been potent symbols of otherness. </p>
<p>Today, to encounter a snake is to brush up against the wild and mysterious heart of the natural world. Snakes are important members of every terrestrial ecosystem across Australia. Even in the most populous parts of the country, snakes inhabit the remnant bushland dispersed throughout our major cities. </p>
<p>But what exactly influences human–snake interactions? Whether you’re hoping to maximise your chances of seeing one of these shy, fascinating critters or wanting to avoid them at all costs, this article is for you.</p>
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<h2>Snakes in southern springtime</h2>
<p>In southern Australia, a flurry of animal activity occurs in spring. As resources start becoming plentiful after the relatively lean months of winter, spring is the reproductive season for many plants and animals. </p>
<p>One such resource is heat — a particularly crucial resource for organisms such as reptiles, which don’t make their own body heat (unlike mammals). It’s a common misconception, however, that snakes want as much heat as they can get. Like Goldilocks, snakes want the temperature to be just right. </p>
<p>Southern springs are the right temperature for snakes to bask during the times of day we humans are also out and about. In summer, snakes, including venomous species such as tiger snakes and brown snakes, are typically more active very early in the morning, late in the evening, or during the night when temperatures are not too high for them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422824/original/file-20210923-15-13vcmkp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">During spring in south-eastern Australia, red-bellied blacksnakes are common in suburban areas.</span>
<span class="attribution"><span class="source">Damian Lettoof</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>After a slow winter, snakes are both hungry (they may have been fasting for months!) and on the lookout for eligible members of the opposite sex. Basking, hunting, and searching for a mate brings snakes out into the open in spring a bit more than at other times of year, so we’re most likely to encounter them during this time.</p>
<h2>Snake activity in northern Australia</h2>
<p>Like all things, snake activity is a little different in the north. Spare a thought for those poor northern Australians who will never know the joys of a snake-filled springtime. </p>
<p>Still, the north has far more snake species than the south, including many species of non-venomous python — the farther south you go, the more our snake fauna is dominated by venomous species (check out <a href="http://www.arod.com.au/arod/">Australian Reptile Online Database</a> for distribution maps).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422836/original/file-20210923-22-e8ozjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Darwin carpet pythons (<em>Morelia spilota variegata</em>) are most often encountered in the cooler months of the year following the annual wet season.</span>
<span class="attribution"><span class="source">Chris Jolly</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Because of the unforgiving year-round heat across northern Australia, temperature doesn’t drive snake activity as it does in the south. You will rarely see a basking snake in Australia’s Top End, they’re too busy avoiding the heat.</p>
<p>Instead, snake activity is driven by another important resource – rain. In the Top End, this means <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.12990">snakes are most often encountered following the wet season</a> (April–June) when prey and water abound. </p>
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<p>In other, more arid “boom and bust” systems, large rainfall events may only happen every five to ten years. When they do, they can trigger huge flurries of snake activity as the serpents emerge to take advantage of fleetingly available prey.</p>
<h2>Snakes indicate ecosystem health</h2>
<p>From the moment of birth, all species of snake are predatory, although some, like <a href="http://www.arod.com.au/arod/reptilia/Squamata/Elapidae/Brachyurophis">shovel-nosed snakes</a>, prey only upon eggs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422822/original/file-20210923-15-1u7uqly.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Shovel-nosed snakes prey only on eggs.</span>
<span class="attribution"><span class="source">Damian Lettoof</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In some terrestrial Australian ecosystems, snakes are near the top of the food chain. After reaching a certain size, they have few predators of their own. A two-metre coastal taipan in the cane fields of northern Queensland, for example, has more to fear from harvesters than it does from any natural predator. </p>
<p>For large snakes to persist in an environment, they need an abundance of their prey (mice, frogs and lizards), as well as all the species their prey feed upon (invertebrates, even smaller animals, or plants).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422838/original/file-20210923-17-14dxlnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Coastal taipans (<em>Oxyuranus scutellatus</em>) are exceptionally elusive, but when they are (rarely) encountered, it is most often males observed while they are on the hunt for females during northern Australia’s winter.</span>
<span class="attribution"><span class="source">Chris Jolly</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Snakes often also have specific habitat requirements. In general, they need shelter and protection from bigger predators, which might include birds of prey, predatory mammals such as native marsupials or introduced cats and foxes, or other snakes. They also need opportunities for safely regulating their body temperature. </p>
<p>This means a snake will only call a place home if it has both a functioning food-web and the necessary habitat complexity. So remember, if you see snakes in your backyard or local park, it’s a sign the ecosystem is doing pretty well.</p>
<h2>Snakes don’t want to bite you</h2>
<p>Snakes are awesome predators, but no Australian snake is interested in eating a human. In fact, they want as little to do with us giant hairless apes as possible.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=482&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=482&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422813/original/file-20210923-22-1018xx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=482&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Merri Creek in inner-city Melbourne is famously home to many snakes, including tiger snakes, who bask in the sun at springtime.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Why? Because snakes are actually quite vulnerable animals. Compared to many other species, they are small, have no sharp claws or strong limbs, and limited energy to put up a fight — they are basically limbless lizards with different teeth. </p>
<p>For those that possess it, venom is a last resort and only a minority of species —such as taipans, brown snakes, tiger snakes, and death adders — can deliver a life-threatening bite to a person. But snakes would much rather use their venom to subdue prey (that’s what they have it for) than to defend themselves.</p>
<p>When snakes bite humans in Australia, it’s a defensive reaction to a large animal they view as a potential predator. Remember, they can’t understand your intentions, even if those intentions are good. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422823/original/file-20210923-23-1dae3xb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tiger snakes and other venomous snakes won’t bite you if you respect their boundaries.</span>
<span class="attribution"><span class="source">Damian Lettoof</span></span>
</figcaption>
</figure>
<p>If you’re lucky enough to see a wild snake, and if you respect its boundaries and give it personal space, it’s sure to do the same for you. Keep dogs on the lead in snakey areas and educate your kids to be snake-smart from as young as possible. </p>
<p>Even though snakes don’t want to bite, snakebite envenoming can be a life-threatening emergency. Learn <a href="https://biomedicalsciences.unimelb.edu.au/departments/department-of-biochemistry-and-pharmacology/engage/avru/advice-and-resources/first-aid">first aid</a>, and when you go for a walk in one of those sanctuaries of greenery that snakes like as much as we do, carry a compression bandage (or three). </p>
<p>It’s almost certain you will never need it, but it could just save a life.</p>
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Read more:
<a href="https://theconversation.com/does-australia-really-have-the-deadliest-snakes-we-debunk-6-common-myths-145765">Does Australia really have the deadliest snakes? We debunk 6 common myths</a>
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<img src="https://counter.theconversation.com/content/168089/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timothy N. W. Jackson receives funding from the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Chris J Jolly receives funding from National Environmental Science Program (Threatened Species Hub).</span></em></p><p class="fine-print"><em><span>Damian Lettoof receives funding from HWRE. </span></em></p>Whether you’re hoping to maximise your chances of seeing one of these shy, fascinating critters or wanting to avoid them at all costs, this article is for you.Timothy N. W. Jackson, Postdoctoral Research Fellow, Australian Venom Research Unit, The University of MelbourneChris J Jolly, Postdoctoral Research Fellow, Charles Sturt UniversityDamian Lettoof, PhD Candidate, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658812021-08-10T23:08:34Z2021-08-10T23:08:34ZHow venomous snakes got their fangs<figure><img src="https://images.theconversation.com/files/415385/original/file-20210810-27-uyosvw.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C1699%2C1077&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Tontan Travel</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Venomous snakes inject a cocktail of toxins using venom fangs — specialised teeth with grooves or canals running through them to guide the venom into a bite wound. Uniquely among animals, grooved and tubular teeth have evolved many times in snakes.</p>
<p>Our new research, published today in <a href="http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2021.1391">Proceedings of the Royal Society B</a>, reveals this happened via a modification of tooth structures that probably served to help anchor snakes’ teeth in their sockets. In certain species, these structures evolved into grooves running the length of the tooth, which served as a handy conduit to deliver venom. </p>
<p>Of the <a href="http://www.reptile-database.org/db-info/SpeciesStat.html">almost 4,000 species</a> of snakes, about 600 are considered “medically significant”, meaning they can deliver a bite that would require hospital treatment, but many more have small fangs and are only mildly venomous. The <a href="https://en.wikipedia.org/wiki/Snake_venom">appearance of mild venoms</a> is thought to predate the appearance of venom fangs in snakes.</p>
<p>Venom fangs are positioned in one of three main ways: fixed at the back of the mouth, as in crab-eating water snakes, cat-eyed snakes, twig snakes and boomslangs; fixed at the front of the mouth, as in cobras, coral snakes, kraits, taipans and sea snakes; or at the front of the mouth and able to fold backwards or sideways, as in adders, vipers, rattlesnakes and stiletto snakes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of different fang types" src="https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=150&fit=crop&dpr=1 600w, https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=150&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=150&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=189&fit=crop&dpr=1 754w, https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=189&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/415371/original/file-20210810-13-36yzmn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=189&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Types of snake fangs and their position in the mouth. Left, a rear-fanged crab-eating water snake; middle, a taipan with fixed front-fangs; right, a Gaboon viper, a snake with hinged front-fangs that can be folded backwards.</span>
<span class="attribution"><span class="source">Alessandro Palci</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>The repeating history of fangs</h2>
<p>By looking at snakes’ evolutionary tree, we can assume the most recent common ancestor of all fanged snakes was probably fangless. This seems much more likely than the alternative: that fangs were acquired once and then lost independently in dozens of different snake lineages. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-snake-fangs-evolved-to-perfectly-fit-their-food-159932">How snake fangs evolved to perfectly fit their food</a>
</strong>
</em>
</p>
<hr>
<p>So how did snakes repeatedly evolve syringe-like teeth from the simpler cone-shaped teeth of their ancestors?</p>
<p>To address this question, we took a closer look at snake teeth and how they develop. We examined 19 species of snakes, including both venomous and non-venomous species and one early fossil form. We used both traditional methods, such as studying slides under a microscope, and cutting-edge <a href="https://en.wikipedia.org/wiki/X-ray_microtomography">microCT scans</a> and <a href="https://en.wikipedia.org/wiki/Finite_element_method">biomechanical modelling</a>. </p>
<h2>The secret to snake teeth: dental origami</h2>
<p>We found that nearly all snakes — whether venomous or not — have teeth that are tightly infolded at their base, and look wrinkly in cross-section (the wrinkles in the red part of the diagram below).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of taipan skull showing fangs and venom groove" src="https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=190&fit=crop&dpr=1 600w, https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=190&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=190&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=238&fit=crop&dpr=1 754w, https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=238&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/415372/original/file-20210810-21-1jo6ebz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=238&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The skull of a taipan, a venomous snake, showing a close-up of its left fang sectioned longitudinally and transversely to show the relationship between plicidentine infoldings at its base and the venom groove.</span>
<span class="attribution"><span class="source">Alessandro Palci</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These folds or wrinkles occur in a tooth layer called dentine, and are known as “plicidentine”, from the Latin word “plica”, meaning “fold”. Plicidentine has been found in many extinct animals and a handful of living fish and lizard species. The function of these folds is not clear, but one theory is they make teeth less likely to break or bend during biting. </p>
<p>However, when we tested this idea using computer simulations on digital tooth models with and without these folds we found that this is not the case. </p>
<p>Snakes replace their teeth throughout their life, rather like sharks, and their teeth do not have deep sockets. So we think the folds could improve the initial attachment of new teeth to shallow sockets by providing a larger area for attachment.</p>
<p>Regardless of the original function of folded snake teeth, what is really interesting is that in venomous snakes, one of those folds is much larger than the others and extends up the tooth to produce a groove: the venom groove. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-some-snakes-so-venomous-22821">Why are some snakes so venomous?</a>
</strong>
</em>
</p>
<hr>
<p>These long, single grooves have occasionally been found in the teeth of other species, such as the venomous <a href="https://www.britannica.com/animal/Gila-monster">Gila monster</a>, which has plicidentine folds and associated grooves in all of its teeth. Importantly, the grooved teeth of the Gila monster can occur in the mouth away from the venom glands, implying a disconnection between the two. We also found that some venomous snakes occasionally have grooves on teeth other than the venom fangs; such teeth are not connected to the venom glands. </p>
<p>So, grooved teeth can occur all over the mouth, even away from the venom glands and their ducts, and we found a clear connection between the presence of plicidentine and venom grooves. This led us to hypothesise that the original condition for venomous snakes could have been that of randomly expressing grooves on their teeth simply as a result of enlarged plicidentine folds, independently of venom glands.</p>
<p>Next, we looked at how the grooved fangs and venom glands of venomous snakes could have evolved together to become an efficient structure for delivering venom. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Venom fang of Gaboon viper" src="https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/415387/original/file-20210810-21-1crfwvy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=402&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Venom fang of a Gaboon viper, with the venom groove running along the top.</span>
<span class="attribution"><span class="source">Alessandro Palci</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Among the ancestors of today’s venomous species, the presence of venom glands (or their precursors, the modified salivary glands called Duvernoy’s glands) was an important prerequisite for the refinement of grooved teeth into enlarged venom fangs. </p>
<p>We think that when a grooved tooth appeared near the discharge orifice of the venom gland, natural selection likely favoured its increase in size and efficiency, as that tooth was more effective at injecting venom. </p>
<p>This refining evolutionary process would eventually produce the large, syringe-like fangs we see today in snakes such as cobras and vipers, where the edges of the groove meet to form a needle-like tubular structure.</p>
<p>This discovery shows how a simple ancestral feature, such as plicidentine (wrinkles on the tooth base likely related to tooth attachment), can be modified and re-purposed for a completely new function (a groove for venom injection). And this could help explain why snakes, uniquely among all animals, have evolved venomous fangs so many times.</p><img src="https://counter.theconversation.com/content/165881/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alessandro Palci is affiliated with Flinders University and the South Australian Museum, and receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Aaron LeBlanc currently receives funding from the European Commission for a Marie Curie Postdoctoral Fellowship and previously received funding from the Natural Sciences and Engineering Research Council of Canada for a Postdoctoral Fellowship.</span></em></p><p class="fine-print"><em><span>Dr Olga Panagiotopoulou is affiliated with Monash University, Australia and previously received funding from EU Marie Curie and Biotechnology and Biological Sciences Research Council (BBSRC). </span></em></p>How have snakes evolved venom fangs so many times in their evolutionary history? Research suggests it’s due to a structure called ‘plicidentine’ in their teeth that can evolve into venom grooves.Alessandro Palci, Research Associate in Evolutionary Biology, Flinders UniversityAaron LeBlanc, Postdoctoral Fellow in Vertebrate Palaeontology, King's College LondonOlga Panagiotopoulou, Senior lecturer, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1535702021-01-21T19:00:09Z2021-01-21T19:00:09ZSpitting cobras may have evolved unique venom to defend from ancient humans<figure><img src="https://images.theconversation.com/files/379529/original/file-20210119-23-13mrf32.jpg?ixlib=rb-1.1.0&rect=247%2C113%2C3077%2C2198&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spitting cobras use their venom for defence.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mozambique-spitting-cobra-naja-mossambica-venom-97045964">Stu Porter/shutterstock.com</a></span></figcaption></figure><p>Cobras are fascinating and frightening creatures. These snakes are most well known for their characteristic defence mechanism called hooding, when the sides of their neck flare out in a dramatic display.</p>
<p>However, hooding isn’t the only defensive behaviour in a cobra’s arsenal. Some species of cobra have modified fangs with small, front facing orifices. These allow them to forcibly eject venom as a spray or “spit”, which can hit the eyes of a target <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1995.tb02743.x">up to 2.5 metres</a> away. For this behaviour, they are known as spitting cobras.</p>
<p>Bizarrely, this unique adaptation has evolved three times independently in a small group of Afro-Asian snakes: once in African cobras, once in Asian cobras, and once in the related rinkhals, also known as the ring-necked spitting cobra.</p>
<p>While most snakes use venom for preying on other animals, spitting cobras use it purely for defence. In <a href="https://doi.org/10.1126/science.abb9303">a new study</a>, we tested the venom of spitting cobras to see what toxins could be found, to work out what might have caused this defensive behaviour to evolve. The results show it might have been to ward off attacks from our human ancestors.</p>
<figure class="align-center ">
<img alt="A spitting cobra." src="https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/379539/original/file-20210119-23-1v5h3g1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spitting cobras can hit the eyes of a target up to 2.5 metres away with venom.</span>
<span class="attribution"><span class="source">Wolfgang Wüster</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Unique toxin cocktails</h2>
<p>Snake venoms are complex mixtures of proteins, used primarily in foraging to efficiently incapacitate prey. While snakes do use their venom in self defence, for example in the case of <a href="https://doi.org/10.1038/nrdp.2017.63">human snakebites</a>, most of the evidence suggests venom composition has been evolved for foraging, <a href="https://theconversation.com/why-do-snakes-produce-venom-not-for-self-defence-study-shows-134189">not defence</a>. </p>
<p>Venom in fixed front-fanged snakes, including cobras, tends to cause paralysis. This is due to an abundance of toxins called neurotoxic three-finger toxins, which stop neurotransmission, signals being sent from the nervous system to the prey’s muscles. However, cobras have a unique type of three-finger toxins that destroy cells, rather than block neurotransmission. These are called cytotoxins. </p>
<p>Our results found spitting cobras have increased the abundance of a different toxin family, called phospholipase A2 (PLA2s), in their venom compared to their non spitting counterparts. Because these cobras spit for defensive reasons, this is the first evidence of a defensive driver of venom evolution in snakes. </p>
<h2>Toxic teamwork</h2>
<p>Many animals that use venom defensively do so by inflicting rapid, severe pain <a href="https://www.pnas.org/content/80/11/3382">on their aggressors</a>. We set out to find out whether defensive spitting cobra venom would be especially painful on contact.</p>
<p>To assess pain causing activity, we tested cobra venom on isolated mouse neurons, responsible for sensations in the eyes and face. We suspected spitting cobra PLA2s might activate these neurons and potentially cause pain.</p>
<p>To our surprise, PLA2s were ineffective on their own. It was the cytotoxins, the toxins widespread in spitting and non-spitting cobras alike, that caused activation of the neurons. However, the mixture of PLA2s and cytotoxins caused this activity to increase dramatically.</p>
<p>This suggests spitting cobras increased the abundance of PLA2s in their venom over time, to make the already present cytotoxins much more effective as a pain inducer. The threefold independent evolution of spitting was accompanied on each occasion by the same complex, synergistic changes in venom composition.</p>
<h2>Could human ancestors have prompted this evolution?</h2>
<p>Venom spitting is a unique behaviour found only in a small handful of closely related snake species. Yet this projectile defence system, and the specific mixture of toxins that cause more pain, evolved three times independently, only within this small group.</p>
<p>This kind of defence must have been stimulated by a very strong selective pressure. We believe several factors make human ancestors the most likely selective agent.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/I6mD9vfsX6o?wmode=transparent&start=1" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Secrets of the spitting cobra.</span></figcaption>
</figure>
<p>Many primates will <a href="https://www.journals.uchicago.edu/doi/abs/10.1086/692830">pre-emptively kill a snake</a> if they <a href="https://www.pnas.org/content/108/52/E1470">feel threatened</a>, often using projectile weapons or tools, like rocks and sticks. While these may not always be lethal, they can cause severe damage. Bipedal hominins, human ancestors who walked on two legs with forelimbs freed, almost certainly posed an even greater long-distance threat compared to their four-legged relatives. This requires a long distance defence from their serpentine enemies, like spitting.</p>
<p>The timing of the evolution of venom spitting coincides with key dates in the evolution of early human ancestors. The emergence of spitting in African cobras occurred at around the same time as the separation of hominins from the chimpanzees and bonobos lineage, <a href="https://nyuscholars.nyu.edu/en/publications/primate-phylogenetic-relationships-and-divergence-dates-inferred-">approximately 7 million years ago</a>. The evolution of spitting in Asian cobras occurred alongside the arrival of <a href="https://www.sciencedirect.com/science/article/pii/S1631068316300410"> <em>Homo erectus</em> in Asia</a> around 2.5 million years ago.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-snakes-produce-venom-not-for-self-defence-study-shows-134189">Why do snakes produce venom? Not for self-defence, study shows</a>
</strong>
</em>
</p>
<hr>
<p>In addition, fossils of spitting cobra fangs have been found in ancient hominin sites such as the <a href="https://www.jstor.org/stable/26558414?seq=1">cradle of humanity in Africa</a>. Current evidence is circumstantial, which means we require more proof. However, venom spitting as a response to trampling by herd animals or being preyed on by birds or mammals is far less supported. </p>
<p>Additional fossils might support or refute our hypothesis. In particular, finding <a href="https://www.researchgate.net/publication/279767147_Amphibia_and_Squamata">the fossilised remains of spitting cobras</a> that predate the divergence between hominins and chimpanzees would refute our hypothesis.</p>
<p>If our distant ancestors’ tendency to attack snakes with rocks or sticks did trigger the evolution of a specific defensive adaptation in snakes, one that persists to this day, we should ponder our own place in Earth history. Rather than being a lineage apart, our human ancestors might have had a direct impact on how these animals evolved.</p><img src="https://counter.theconversation.com/content/153570/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Casewell receives funding from the Wellcome Trust, Royal Society, Medical Research Council, NIHR and DFID.</span></em></p><p class="fine-print"><em><span>Wolfgang Wüster receives funding from The Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Harry Greene and Taline Kazandjian do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A toxin unique to spitting cobras means their venom causes more pain than other snakes.Taline Kazandjian, Postdoctoral Research Assistant, Liverpool School of Tropical MedicineHarry Greene, Professor of Ecology and Evolutionary Biology , Cornell UniversityNicholas Casewell, Director of Centre for Snakebite Research & Interventions, Liverpool School of Tropical MedicineWolfgang Wüster, Reader in Zoology, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1507832021-01-03T18:56:19Z2021-01-03T18:56:19Z‘Good luck fella, stay safe’: a snake catcher explains why our fear of brown snakes is misplaced<figure><img src="https://images.theconversation.com/files/375299/original/file-20201216-13-1cmaqa4.jpg?ixlib=rb-1.1.0&rect=0%2C24%2C5472%2C3612&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Sun, sea … snakes: all three are synonymous with the Australian summer, but only the first two are broadly welcomed. And of all Australia’s snake species, brown snakes are among the most feared. </p>
<p>To some degree, this is understandable. Brown snakes are alert, nervy and lightning-fast over short distances. When threatened, they put on a spectacular (and intimidating) defensive display, lifting the front half of their body vertically, ready to strike.</p>
<p>They are also fairly common, and well adapted to suburban life – especially the eastern brown species. And of course, certain species have a highly toxic venom designed to immobilise the mammals they prey on. </p>
<p>Besides my work as a sociologist, I’m also a professional snake catcher and handle scores of venomous snakes during the warmer months. I don’t expect people to love snakes, but I believe greater knowledge about them will help with their being respected more as keystone ecological creatures.</p>
<figure class="align-center ">
<img alt="The author catching a brown snake." src="https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=829&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=829&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374979/original/file-20201214-17-eexr5f.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=829&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The author catching a brown snake. He wants to garner public respect for the creatures.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<h2>Not just wicked serpents</h2>
<p>Around two Australians <a href="https://www.theguardian.com/australia-news/2020/jan/31/tasmanian-sheep-farmer-dies-after-being-bitten-by-tiger-snake">die each year</a> from snake bites, and the brown snake family causes the most human – and likely pet – fatalities. But compare that figure with the annual road toll (<a href="https://www.bitre.gov.au/sites/default/files/documents/rda_dec_2019.pdf">1,188 deaths in 2019</a>) or the 77 people <a href="https://www.abc.net.au/news/2018-11-27/sharks-snakes-crocodiles-horses-australias-most-dangerous/10534786?nw=0&pfmredir=sm">killed by horses and cows</a> in Australia between 2008 and 2017. You can see why many herpetologists – or snake experts – feel our fear of snakes is somewhat misplaced.</p>
<p>Where does this fear come from, then? It partly arises from the representation of snakes throughout human history as menacing. The fact snakes are cold-blooded, with an unblinking stare, means humans have often depicted them as callous and cold-hearted. Examples include the serpent who <a href="https://bibleinterp.arizona.edu/articles/2015/04/day398028">corrupts Eve</a> in the Book of Genesis, and monstrous mythological characters such as <a href="https://www.history.com/news/snake-symbol-history-mythology">Medusa</a>.</p>
<p>Partly because of these and other depictions, snakes are often considered something to be feared. When they slither into our manicured back yards, they are seen as a “problem” that has transgressed our sanitised domestic lives. And this fear is often transferred down the generations.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/does-australia-really-have-the-deadliest-snakes-we-debunk-6-common-myths-145765">Does Australia really have the deadliest snakes? We debunk 6 common myths</a>
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</em>
</p>
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<p>In my snake-catching work, I have extricated snakes from backyards and homes, a shopping centre, parks and school classrooms. I’ve even removed snakes from a woman’s boot, under a soccer team’s kit bag and inside a weapons bunker! About 85% of the snakes I work with on callouts are eastern browns.</p>
<p>Many callers wanting a snake removed experience intense emotions, from shock and hostility to awe and reverence. Most want the snake taken as far away from their property as possible.</p>
<p>After catching a snake, I release it into a suitable non-residential environment. I always wonder what happens to it next. The threats snakes face are numerous. They can be harmed or killed by humans, pets, feral animals or predators. They are also threatened by habitat loss, climate events and contaminated prey items. </p>
<p>I release each with the departing words: “Good luck fella, stay safe, stay out of trouble.”</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/7tGziMNCybs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<h2>Tracking snake movements</h2>
<p>Eastern brown snakes are timid and reluctant to strike unless provoked. They are generally solitary animals except during breeding periods. They perform a crucial ecological role by eating vermin such as mice and rats, controlling the numbers of other native species and providing a food source for various animals. </p>
<p>Information on how brown snakes move through and use urban space is limited. We urgently need more understanding of their daily habits, especially as urban development encroaches on their natural habitat, increasing the chances of conflict with humans or pets. More insight is also needed on whether it’s damaging to relocate hundreds of snakes each year. </p>
<p>A study in Canberra funded by the Ginninderry Conservation Trust aims to answer these issues. A team of researchers, including myself, will track the movements of 12 eastern brown snakes in the urban environment. We will do this using telemetry – tracking technologies fitted to the snakes. Some devices will be implanted into the snake under the skin, and others attached externally above the tail.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ive-always-wondered-who-would-win-in-a-fight-between-the-black-mamba-and-the-inland-taipan-129906">I've always wondered: who would win in a fight between the Black Mamba and the Inland Taipan?</a>
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</em>
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<p>We will examine:</p>
<ul>
<li><p>movements of adult male and female eastern browns</p></li>
<li><p>how far they travel</p></li>
<li><p>the times of day and temperatures when they are active</p></li>
<li><p>where they go dormant in the cooler months</p></li>
<li><p>the refuges they use to navigate the hostile environment they live in.</p></li>
</ul>
<p>Our team will also explore the effects of catching a snake and releasing it into new habitat within a designated range (5km in the ACT, and 20km in NSW). We will examine how the snake responds to the stress of being captured and moved, the risks it might confront in an unfamiliar landscape, and whether it survives. We will also explore the implications for other snakes in the release habitat and the genetic consequences of interbreeding between geographically distinct populations.</p>
<figure class="align-center ">
<img alt="A brown snake under a log." src="https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375302/original/file-20201216-13-t9hpam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&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 study will examine how snakes move through the urban landscape.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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</figure>
<h2>Knowledge breeds greater tolerance</h2>
<p>We anticipate the study’s findings will help educate the public about how snakes operate in suburbia. It will also inform translocation policies and conservation efforts.</p>
<p>We also hope to show how eastern browns are vital – not superfluous or undesirable – parts of thriving ecosystems. The better we understand snakes, the less we might fear them. This may also mean we are less disposed to relocating or harming them.</p><img src="https://counter.theconversation.com/content/150783/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gavin JD Smith receives funding from the Ginninderry Conservation Trust.</span></em></p>As well as my work as a sociologist, I’m also a professional snake catcher. I don’t expect people to love snakes, but I believe they should know more about them - and it’s not all bad.Gavin JD Smith, Associate Professor in Sociology, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1213862019-09-12T12:59:29Z2019-09-12T12:59:29ZWhy knowing what black mamba venom does to the human body is crucial<figure><img src="https://images.theconversation.com/files/286755/original/file-20190802-117861-h5lp88.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Black mamba venom can be lethal.</span> <span class="attribution"><span class="source">Photograph courtesy Thomas Birkenbach </span></span></figcaption></figure><p><a href="https://www.nationalgeographic.com/animals/reptiles/b/black-mamba/">Black mambas</a> are extremely dangerous reptiles – in fact, many consider the species to be one of the world’s deadliest snakes. They are found in southern and eastern Africa, and are shy, evasive creatures. They won’t seek out human interaction. But if cornered or confronted, they will strike. And their venom is lethal. </p>
<p>Black mambas (don’t let the name fool you – they’re very rarely black, and are more usually a dark brown – it is the inside of the mouth which is black) probably cause the largest number of <a href="https://www.africansnakebiteinstitute.com/snakebite/">snake-related deaths</a> in southern Africa. In a recent case, a South African judge <a href="https://www.timeslive.co.za/news/south-africa/2019-05-21-sa-judge-dies-from-black-mamba-bite-on-zambia-holiday/">died after being bitten by a black mamba</a> while he was travelling in Zambia. But the data for the whole continent is limited, so the precise number isn’t known. This is chiefly because most of these deaths occur in rural parts of Africa with limited health infrastructure and other resources. </p>
<p>Sub-optimal mortuary facilities, inadequate professional manpower, poorly developed protocols and the lack of an efficient and reliable toxicology service means many of these deaths in Africa’s more rural areas are not properly diagnosed. It is most likely that these snakebite victims get buried without a thorough forensic pathological autopsy.</p>
<p>The black mamba is born with two to three drops of venom per fang. It is a front-fanged snake, with fangs up to 6.5 mm in length, located at the front of the upper jaw. An adult of the species has between 12 and 20 drops per fang. It takes just <a href="http://www.krugerpark.co.za/krugerpark-times-17-facts-about-the-black-mamba.html">two drops of venom</a> to kill an adult human. This means that even young black mambas are extremely dangerous.</p>
<p>Not much is known about the pathology of trauma of black mamba bites – that is, what the black mamba’s toxin does, physically, inside a victim’s system. We do know that the venom is neurotoxic and cardiotoxic. That means that it has a direct effect on the nerves and the heart.</p>
<p>The more we know, the better. If we know precisely what the toxin does, hospitals and clinics might be better prepared to treat those who’ve been bitten. </p>
<h2>A recent case study</h2>
<p>Recently my colleagues and I <a href="https://europepmc.org/abstract/med/31318708">examined</a> the case of a young man who was bitten by a black mamba in South Africa. He arrived at the hospital 20 minutes after being bitten and had already suffered cardiac arrest with accompanying hypoxic brain injury.</p>
<p>This was my third encounter with the victim of a black mamba bite. My first fatal encounter, in 2000, involved a 12-year-old girl who was bitten on the thigh by a black mamba. The second involved a British tourist who was accidentally bitten at a snake park, and who also died.</p>
<p>In this latest case, the co-workers of the young man who died were certain that the snake was a black mamba. This gave us, as forensic pathologists, an excellent opportunity to thoroughly investigate this matter. Oftentimes, the history is scant, with victims unable to properly identify the snake which bit them.</p>
<p>The forensic examination consists of a thorough macroscopic post mortem examination, followed by histological (microscopic) examination and blood tests. </p>
<p>A black mamba’s venom is complex. It interferes with transmission across the motor end-plate, which is where the nerves and muscles connect, so it will result in paralysis. The venom is also cardiotoxic, which means it may have a direct effect on the heart. </p>
<h2>How to treat it</h2>
<p>So what should you do if you or someone around you is bitten by a black mamba? </p>
<p>The first priority is to transport the victim to an appropriate medical facility as soon as possible. First-aid should focus on maintaining vital functions, such as respiratory support. Keep the victim still and try limit any unnecessary movement. Remove constricting items (for example rings and clothing), especially those close to the bite site. </p>
<p>The first-aid treatment of black mamba bites includes lymphatic retardation with the pressure immobilisation technique – in other words try and wrap a tight crepe bandage or tourniquet close to the bite site. </p>
<p>Medical management comprises continuous monitoring, making sure the airways are open, treating symptoms and the immediate administration of antivenom. The antivenom is injected intravenously because absorption is poor via the muscles. It’s also important not to inject into or around the bite site. In rare instances the victim may be put on <a href="https://heart.bmj.com/content/105/18/1437">extracorporeal membrane oxygenation</a>, which is a way of providing prolonged cardiac and respiratory support to those whose heart and lungs are unable to provide oxygen to the body.</p>
<p>This combination of respiratory support and antivenom may save a person’s life. Over time, the antivenom will ease muscle paralysis and set the victim on the road to recovery.</p><img src="https://counter.theconversation.com/content/121386/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Blumenthal 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>Not much is known about the pathology of trauma of black mamba bites – that is, what the black mamba’s toxin does, physically, inside a victim’s system.Ryan Blumenthal, Senior Specialist, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1136192019-03-21T13:29:55Z2019-03-21T13:29:55ZSnake venom can vary in a single species — and it’s not just about adaptation to their prey<p>Few sights and sounds are as emblematic of the North American southwest as a defensive rattlesnake, <a href="https://www.youtube.com/watch?v=XkyKliH1X3c">reared up, buzzing, and ready to strike</a>. The message is loud and clear, “Back off! If you don’t hurt me, I won’t hurt you.” Any intruders who fail to heed the warning can expect to fall victim to a venomous bite. </p>
<p>But the consequences of that bite are surprisingly unpredictable. Snake venoms are complex cocktails made up of dozens of individual toxins that attack different parts of the target’s body. The composition of these cocktails is highly variable, even within single species. Biologists have come to assume that most of this variation reflects adaptation to what prey the snakes eat in the wild. But <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2018.2735">our study</a> of the Mohave rattlesnake (<em>Crotalus scutulatus</em>, also known as the Mojave rattlesnake) has uncovered an intriguing exception to this rule.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264483/original/file-20190318-28512-19ykw6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">What’s in those glands? It depends where you are!</span>
<span class="attribution"><span class="source">W. Wüster</span></span>
</figcaption>
</figure>
<p>A 20-minute drive can take you from a population of this rattlesnake species with a highly lethal neurotoxic venom, <a href="https://www.ncbi.nlm.nih.gov/pubmed/11990148">causing paralysis and shock</a>, to one with a haemotoxic venom, causing <a href="https://www.sciencedirect.com/science/article/pii/0041010183900545">swelling, bruising, blistering and bleeding</a>. The neurotoxic venom (known as venom A) can be more than ten times as lethal as the haemotoxic venom (venom B), at least to lab mice. </p>
<p>The Mohave rattlesnake is not alone in having different venoms like this – several other rattlesnake species display the <a href="https://www.sciencedirect.com/science/article/pii/0041010185900145">same variation</a>. But why do we see these differences? Snake venom evolved to subdue and kill prey. One venom may be better at killing one prey species, while another may be more toxic to different prey. Natural selection should favour different venoms in snakes eating different prey – it’s a classic example of evolution through natural selection.</p>
<p>This idea that snake venom varies due to adaptation to eating different prey has become <a href="https://www.sciencedirect.com/science/article/pii/S0169534712002935">widely accepted</a> among herpetologists and toxinologists. Some have found <a href="https://www.nature.com/articles/379537a0">correlations</a> between venom and prey. Others have shown <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2009.0048">prey-specific lethality</a> of venoms, or identified toxins <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2018.1003">fine-tuned for killing the snakes’ natural prey</a>. The venom of some snakes even <a href="https://www.jstor.org/stable/3893080">changes along with their diet as they grow</a>. </p>
<p>We expected the Mohave rattlesnake to be a prime example of this phenomenon. The extreme differences in venom composition, toxicity and mode of action (whether it is neurotoxic or haemotoxic) seem an obvious target for natural selection for different prey. And yet, when we correlated differences in venom composition with regional diet, we were shocked to find there is no link.</p>
<h2>Variable venoms</h2>
<p>In the absence of adaptation to local diet, we expected to see <a href="https://www.ncbi.nlm.nih.gov/pubmed/30395254">a connection between</a> gene flow (transfer of genetic material between populations) and venom composition. Populations with ample gene flow would be expected to have more similar venoms than populations that are genetically less connected. But once again, we drew a blank – there is no link between gene flow and venom. This finding, together with the geographic segregation of the two populations with different venoms, suggests that instead there is strong local selection for venom type. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=522&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=522&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=522&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=656&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=656&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264481/original/file-20190318-28475-1ft443x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=656&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mohave rattlesnake feeding on a kangaroo rat, one of its most common prey items.</span>
<span class="attribution"><span class="source">W. Wüster</span></span>
</figcaption>
</figure>
<p>The next step in our research was to test for links between venom and the physical environment. Finally, we found some associations. The haemotoxic venom is found in rattlesnakes which live in an area which experiences warmer temperatures and more consistently low rainfall compared to where the rattlesnakes with the neurotoxic venom are found. But even this finding is deeply puzzling. </p>
<p>It has been suggested that, as well as killing prey, venom <a href="https://www.sciencedirect.com/science/article/pii/0041010179902113">may also help digestion</a>. Rattlesnakes eat large prey in one piece, and then have to digest it in a race against decay. A venom that starts predigesting the prey from the inside could help, especially in cooler climates where digestion is more difficult. </p>
<p>But the rattlesnakes with haemotoxic venom B, which better aids digestion, are found in warmer places, while snakes from cooler upland deserts invariably produce the non-digestive, neurotoxic venom A. Yet again, none of the conventional explanations make sense.</p>
<p>Clearly, the selective forces behind the extreme venom variation in the Mohave rattlesnake are complex and subtle. A link to diet may yet be found, perhaps through different kinds of <a href="https://academic.oup.com/icb/article/56/5/1032/2420622">venom resistance</a> in key prey species, or prey dynamics affected by local climate. In any case, our results reopen the discussion on the drivers of venom composition, and caution against the simplistic assumption that all venom variation is driven by the species composition of regional diets.</p>
<p>From a human perspective, variation in venom composition is the bane of anyone working on snakebite treatments, or antidote development. It can lead to unexpected symptoms, and <a href="https://www.ncbi.nlm.nih.gov/pubmed/28847519">antivenoms may not work</a> against some populations of a species they supposedly cover. Anyone living within the range of the Mohave rattlesnake can rest easy though – the available antivenoms cover both main venom types. </p>
<p>Globally, however, our study underlines the unpredictability of venom variation, and shows again that there are no shortcuts to understanding it. Those developing antivenoms need to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767246/">identify regional venom variants and carry out extensive testing</a> to ensure that their products are effective against all intended venoms.</p><img src="https://counter.theconversation.com/content/113619/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wolfgang Wüster receives funding from The Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Giulia Zancolli receives funding from Santander Early Career Research Scholarship. </span></em></p>The Mohave rattlesnake is famous for its variable venom – but the reasons behind that variation are not as straightforward as we thought.Wolfgang Wüster, Senior Lecturer in Zoology, Bangor UniversityGiulia Zancolli, Associate Research Scientist, Université de LausanneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/900522018-02-07T10:16:02Z2018-02-07T10:16:02ZFive ingenious ways snakes manipulate their bodies to hunt and survive<figure><img src="https://images.theconversation.com/files/205245/original/file-20180207-74482-8c6sw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-puff-adder-bitis-arietans-defensive-195965318?src=raKqf9TasrFGHCA9hT-R8Q-1-20">Shutterstock</a></span></figcaption></figure><p>Do a quick search for “snakes” in the news and you’ll find people terrified, bitten or, sadly, killed by these creatures. Many of us fear their slithering ways and researchers have found evidence which suggests that humans have evolved a <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0164342">tendency to spot snakes</a> more easily than other animals. </p>
<p>But there are more than 3,500 species of snake in the world, and they have been around <a href="https://www.reuters.com/article/us-science-snakes/remarkable-fossils-push-back-snake-origins-by-65-million-years-idUSKBN0L02CM20150127">for 167m years</a> – so they must be doing something right.</p>
<p>Although it seems strange to us, snakes’ lack of legs mean that they have evolved numerous fantastic techniques to survive, making ingenious use of their cylindrical forms.</p>
<h2>1. Some snakes can travel in straight lines</h2>
<p>The majority of snakes bend their spines and exert force on the ground, trees, or water with the bends in their body or the edges of their coils to move. But some can travel in a <a href="http://magazine.uc.edu/editors_picks/recent_features/locomotion.html">perfectly straight line</a>. Until recently, it was a mystery how they accomplished this, but <a href="http://jeb.biologists.org/content/early/2017/12/05/jeb.166199">new research</a> demonstrates that Boa constrictors and other heavy bodied snakes use their belly scales like a tyre tread to seamlessly progress in a straight line. </p>
<p>Three sets of muscles work in union, with the first yanking the belly skin and scales forward. Meanwhile, the second shortens the skin as the belly scales move forward and come together, before pinning them in place as the third set brings the spinal column forward. This allows the snake to move forward at nearly constant speed, but they only do it when they are relaxed. A frightened snake in need of speed will revert to a more typical mode of locomotion. </p>
<p>Moving like this is thought to benefit snakes which spend time underground in narrow holes, allowing them to squeeze into animal burrows in search of refuge or prey. </p>
<h2>2. Puff adders use their tongues as bait</h2>
<p>Widespread across the grassy woodlands of sub-Saharan Africa and parts of the Arabian Peninsula is a chunky venomous snake called the <a href="http://eol.org/pages/1057058/details">puff adder</a> (<em>Bitis arietans</em>), so named for its habit of hissing loudly when disturbed. Puff adders are successful predators of small mammals, lizards, frogs and birds, but <a href="https://link.springer.com/article/10.1007/s00265-016-2244-6">until recently</a> one secret to their success was unknown.</p>
<p>Upon spotting a frog nearby, the puff adder begins flicking its tongue unusually slowly, seemingly mimicking a small worm. To frogs, juicy worms are irresistible, and their eagerness to eat them leads them straight into the waiting mouth of the viper. This <a href="https://theconversation.com/new-puff-adder-behaviour-uncovered-it-uses-two-ways-to-entice-its-prey-72811">hunting strategy</a> is known as lingual luring.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3umGcQw-JWA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>3. Mock viper eyes change shape</h2>
<p>While it is gifted with one of the most impressive scientific names of any snake – <em>Psammodynastes pulverulentus</em>, a mixture of ancient Greek and Latin meaning “dusty sand ruler” – the <a href="http://eol.org/pages/461884/overview">mock viper</a>, unlike the puff adder, does not possess deadly venom. Living in the forested areas of south and southeast Asia, the mock viper is surrounded by dangerous animals such as leopard cats and is subject to the possibility of being eaten on a daily basis. To counter this and intimidate would-be predators, the mock viper earns its name by physically resembling a viper, possessing the well-defined triangular head that characterises real vipers in the area.</p>
<p>This disguise is not enough for these snakes, though. When threatened with imminent danger, the mock viper <a href="http://onlinelibrary.wiley.com/doi/10.1002/fee.1420/full">alters the shape of its pupil</a> from round to a thin, vertical slit. These “elliptical pupils” are typical of actual vipers in the area. It is thought that this last-ditch defence may be enough to persuade a predator to think twice and allow the mock viper to slither to safety.</p>
<h2>4. Boas line up to catch prey</h2>
<p>In Cuba’s <a href="http://whc.unesco.org/en/list/889">Desembarco del Granma national park</a>, Jamaican fruit bats have found their ideal home in the chambers of sinkhole caves – deep holes sunk vertically into the ground. Unfortunately, it is no easy life: <a href="http://eol.org/pages/38759183/overview">Cuban boas </a>(<em>Chilabothrus angulifer</em>), large, constricting snakes with striking zigzag patterns, also live around these caves, and have developed a taste for the bats.</p>
<p>Though the bats spend the daytime comfortably roosted deep in the caves, they leave every evening to forage for fruit. The boas take up position on the cave ceiling late in the evening and wait for this nightly passage to take place. But their positioning is <a href="http://animalbehaviorandcognition.org/uploads/journals/14/02%20Feb2017%20Dinets_HH(7)_final.pdf">not random</a>. The boas spread themselves in a line, forming a rudimentary barrier. This coordinated hunting increases their chances of catching a bat because their prey has no choice but to fly past a snake to exit the cave.</p>
<h2>5. Sea snakes tie themselves in knots</h2>
<p>Sea snakes spend their entire lives in water, even giving birth to live young in the ocean. They have many adaptations to survive including a flat, paddle shaped tail, and an ability to excrete salt using a <a href="http://science.sciencemag.org/content/173/3995/437">gland under the tongue</a>. </p>
<p>Despite their name, <a href="http://eol.org/pages/37135449/overview">yellow-bellied sea snakes</a> (<em>Hydrophis platurus</em>) are not cowardly, but rather possess bright yellow undersides. These snakes have developed a bizarre strategy to help them shed their old skin. Because there is not much in the open sea to rub up against to loosen the skin, they actually <a href="http://www.jstor.org/stable/1442853?casa_token=AqJQZmDX07EAAAAA:ywzNnJJm07cCxP1y1c9ISzpEM8Fq1H0w0SNLsOOyPE-Gw2tq6wQErL6J2Z73jxKTZKHHkUxYdLp_P7Ih1t69-eRmSGRscenP2lKTjcc6ZnDxUT67VfU&seq=1#page_scan_tab_contents">tie themselves in a knot</a>, using their own bodies as a scratching post to remove it in one piece, much like peeling off a sock.</p><img src="https://counter.theconversation.com/content/90052/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Major 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>Snakes have survived millions of years by using their bodies in increasingly creative ways.Tom Major, PhD candidate in Biological Sciences, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/809822017-07-20T17:58:12Z2017-07-20T17:58:12ZSnakebites still exact a high toll in Africa. A shortage of antivenoms is to blame<figure><img src="https://images.theconversation.com/files/178650/original/file-20170718-10334-1b8s0tu.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">Shutterstock</span></span></figcaption></figure><p>A snakebite is one of the most excruciating experiences a person can go through. Depending on how venomous the snake is, it can cause morbidity, pain, and death. Snakebite envenoming can lead to paralysis of the nerves and muscles, local tissue damage and the death of cells in an organ, haemorrhaging, and it may interfere with the blood’s ability to coagulate.</p>
<p>Snakebites are a major public health issue in most tropical parts of the world, where <a href="http://www.who.int/mediacentre/factsheets/fs337/en/">more than 5 million bites occur each year</a>. This leads to more than 150,000 deaths and about three times as many amputations. Poor people living in snake infested areas are the worst affected. But in sub-Saharan Africa, victims not only suffer from the snakebite, but also from a lack of effective treatment options. Only <a href="http://www.sciencedirect.com/science/article/pii/S1874391911002181?via%3Dihub">about 2% of victims receive antivenom</a>.</p>
<p>Antivenoms that are made from serum from large mammals, immunised with snake venom are the mainstay of treating snakebites. But they are in short supply in sub-Saharan Africa, as they are costly to manufacture, and limited financial incentive holds the development of new antivenoms.</p>
<p>In an effort to overcome the shortage of antivenoms, the global snakebite community has declared <a href="http://www.nature.com/news/africa-braced-for-snakebite-crisis-1.18357">an antivenom crisis</a>. These efforts have brought international attention from both private foundations, researchers, and the World Health Organisation to this neglected tropical disease.</p>
<h2>Africa’s venomous snakes</h2>
<p>Two main snake families that cause the most dangerous snakebites in sub-Saharan Africa are – <a href="https://www.livescience.com/54023-vipers.html">vipers</a> and <a href="https://www.britannica.com/animal/elapid">elapids</a>. The viper family has a number of species, like the gaboon viper (<em>Bitis gabonica</em>), which holds the world record for the largest fangs. The carpet viper (<em>Echis ocellatus</em>) has the highest death toll of any snake. The elapid snake family includes neurotoxic cobras, spitting cobras, and mambas. It also holds the most notorious snake of them all, <a href="http://www.nationalgeographic.com/animals/reptiles/b/black-mamba/">the black mamba (<em>Dendroaspis polylepis</em>)</a>. </p>
<p>The venoms of these two snake families are fundamentally different. The venom of elapid snakes cause toxicity to the entire body. The primary clinical symptoms include paralysis caused by neurotoxins that stops muscles receiving signals from the nerves.</p>
<p>In contrast, viper venoms hold a large arsenal of toxins that destroy tissue and interfere with the bloods ability to clot.</p>
<p>For their part, spitting cobra venoms produce both effects. This includes paralysis as well as cell destruction (or cytotoxicity), which can lead to significant tissue damage in eyes or bitten limbs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178651/original/file-20170718-10341-1o8n8eh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The black mamba is part of the elapid snake family.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Antivenom – the only effective therapy</h2>
<p>The severe effects of bites by both vipers and elapids need to be treated with antivenom. But a scarcity of antivenoms in Africa has had a devastating impact on thousands of victims. Factors leading to this shortage include low profitability for manufacturers (due to high cost of production and low purchasing power of most victims and health care systems affected by snakebite), lack of advocacy, and simply that many researchers and politicians are not aware that snakebites are a pressing issue.</p>
<p>Unfortunately, this isn’t likely to change immediately. </p>
<p>One silver lining is that the World Health Organisation has recently reintroduced snakebite on the <a href="http://www.who.int/neglected_diseases/diseases/en/">list of neglected tropical diseases.</a> This may help create awareness as well as incentives to get <a href="https://theconversation.com/how-biotechnology-could-offer-hope-for-snakebite-victims-68244">antivenoms to the clinic</a>.</p>
<p>There are two types of antivenoms available. </p>
<ol>
<li><p>Those that can neutralise the venom of a single snake species and sometimes closely related ones too. These are known as monovalent antivenoms.</p></li>
<li><p>Antivenoms that neutralise a wider range of snake venoms, these are known as polyvalent antivenoms. </p></li>
</ol>
<p>The benefit of using monovalent antivenoms is that they may have a higher efficacy against bites from the specific species they are raised against. For their part, polyvalent antivenoms are useful because they can be used against a range of different bites. This is particularly helpful when the perpetrating snake hasn’t been identified. </p>
<p>In Africa, only polyvalent antivenoms are on the market due to the existence of many different snake species, difficulties in distinguishing them from each other, and since administration of an incorrect antivenom in a given case is avoided by having only one alternative (for the given geographical region) to choose from. Typically these antivenoms are manufactured to be effective against the venom from several vipers, selected cobras, and <a href="https://www.ncbi.nlm.nih.gov/pubmed/27339430">one to three mamba species.</a>.</p>
<h2>What to do, and not to do</h2>
<p>Symptoms and clinical presentation in patients bitten by a snake can be affected by a number of factors. These include: the snake species, the precondition of the patient, the dose of venom injected, and the availability of treatment options. Symptoms can develop quicker in children. </p>
<p>What’s important is that people, in the first instance, try to identify the snake. Proper identification – like a photo – is highly valuable.</p>
<p>Efforts should be made to ensure that the bitten section is immobilised or kept below the heart to reduce the spread of the venom. The patient should be kept still until help arrives or until safe transport is arranged to a health care facility. Patients bitten by a venomous viper or elapid species should be admitted for at least 12 hours. </p>
<p>If someone’s eyes are exposed to venom they should be washed thoroughly. But no other specific home treatment should be initiated. It’s a really bad idea to cut, suck or wash the bite site. </p>
<p>The numbers of deaths from snakebites won’t be reduced unless more, and preferably less expensive, antivenom is made available. This will require a joint effort between researchers, policymakers, and funding bodies.</p>
<p>Snakebites still claim the lives of many causing much morbidity to humans each year, but recent <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005361">technological developments</a>, <a href="http://www.mdpi.com/2072-6651/8/12/351">rising awareness</a>, and <a href="https://www.statnews.com/2017/06/12/snakebite-who-priority/">increasing political focus</a> may hold the promise for a brighter future for snakebite victims.</p><img src="https://counter.theconversation.com/content/80982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andreas Hougaard Laustsen receives funding from the Novo Nordisk Foundation and the Hørslev Foundation. </span></em></p><p class="fine-print"><em><span>Lotte Høgberg 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>The best cure against a snakebite is to avoid being bitten at all. Here is what you need to know about snakebites, antivenom, and what you need to do if bitten.Andreas Hougaard Laustsen, Associate Professor at the Department of Biotechnology and Biomedicine, Technical University of DenmarkLotte Høgberg, Pharmacist, PhD, at the Danish Poisons Information Center (GIFTLINJEN), Department of Anaesthesiology, Copenhagen University HospitalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/794332017-06-21T20:01:00Z2017-06-21T20:01:00ZA venomous paradox: how deadly are Australia’s snakes?<p>Australia is renowned worldwide for our venomous and poisonous creatures, from snakes, spiders and ticks on land, to lethal jellyfish, stingrays and stonefish in our waters. Even the shy platypus can inflict excruciating pain if handled without due care. </p>
<p>Yet while injuries and deaths caused by venomous snakes and jellyfish are often sensationalised in the media, and feared by international visitors, a recent review found that <a href="http://onlinelibrary.wiley.com/doi/10.1111/imj.13297/full">very few “deadly” Australian animals actually cause deaths</a>. Between 2000 and 2013, there were two fatalities per year from snake bites across Australia, while the average for bee stings was 2.2 and for jellyfish 0.25, or one death every four years. For spiders – including our notorious redbacks and Sydney funnel-webs – the average was zero.</p>
<p>Snakes nevertheless strike fear into many people who live in or visit Australia. When we have a higher risk of injury or death from <a href="http://www.economist.com/news/asia/21722219-public-opinion-favours-deterrence-over-culling-fearsome-fish-australians-debate-how-avoid">burns, horses</a>, <a href="https://theconversation.com/welcome-to-australia-a-land-of-creatures-out-to-kill-you-maybe-71490">bee stings</a>, <a href="http://www.royallifesaving.com.au/__data/assets/pdf_file/0004/18085/RLS_NDR2016_ReportLR.pdf">drownings</a> and <a href="https://bitre.gov.au/publications/ongoing/road_deaths_australia_monthly_bulletins.aspx">car accidents</a>, why don’t we fear these hazards as we do the sight of a snake?</p>
<h2>Snakes and statistics through history</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174111/original/file-20170616-545-1q9iqx0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">James Bray, Venomous and Non-Venomous Reptiles (1897).</span>
<span class="attribution"><span class="source">State Library of NSW/Peter Hobbins</span></span>
</figcaption>
</figure>
<p>When settlers arrived in Australia in the late 18th century, they believed that <a href="https://ebooks.adelaide.edu.au/t/tench/watkin/settlement/complete.html">Australian snakes were harmless</a>. By 1805 it was accepted that local serpents might kill humans, but they were hardly feared in the same way as the American rattlesnake or Indian cobra. </p>
<p>Until the 1820s, less than one human death from snake bite was recorded each year; in 1827 visiting surgeon Peter Cunningham <a href="https://archive.org/stream/twoyearsinnewso03cunngoog#page/n351/mode/2up/search/snake">remarked</a> that:</p>
<blockquote>
<p>…comparatively few deaths [have] taken place from this cause since the foundation of the colony. </p>
</blockquote>
<p>Similar observations were made into the 1840s. What the colonists did note, however, was the significant death toll among their “exotic” imported animals, from cats and sheep to highly valuable horses and oxen. </p>
<p>By the 1850s, living experiments in domestic creatures – especially chickens and dogs – were standard fare for <a href="http://www.manchesteruniversitypress.co.uk/articles/snakebite-science-suffering/">travelling antidote sellers</a>. Given the popularity of these public snake bite demonstrations, from the 1860s, doctors and naturalists also took to experimenting with captive animals. It was during this period that official statistics on deaths began to be collated across the Australian colonies.</p>
<p>One sample from 1864–74, for instance, reported an average of <a href="https://digitised-collections.unimelb.edu.au/bitstream/handle/11343/23139/267595_UDS2010779-231.pdf?sequence=3">four snake bite deaths per year</a> across Victoria, or one death per 175,000 colonists. In contrast, during the same period <a href="https://archive.org/stream/TheThanatophidiaOfIndiaBeingADescriptionOfTheVenomousSnakesOfThe/1874#page/n75/mode/2up/search/hindostan">one in 6,000 Indians</a> died from snake bites each year; little wonder that around the world, Australian snakes were considered trifling.</p>
<p>The 1890s represented a dramatic period of divergence, though. On one hand, <a href="https://archive.org/stream/b28100384#page/154/mode/2up/search/huxtable">statistical studies in 1882–92</a> suggested that on average, 11 people died annually from snake bite across Australia. Similar data compiled in Victoria led physician James Barrett to <a href="http://www.biodiversitylibrary.org/item/34434#page/231/mode/1up">declare in 1892</a> that snakes posed “one of the most insignificant causes of death in our midst”. On the other hand, by 1895 standardised laboratory studies, aimed especially at producing an effective antivenom, saw a <a href="http://biodiversitylibrary.org/page/4182286">global recognition</a> that Australian snake venoms were among the most potent in the world. </p>
<p>In Sydney, physiologist Charles Martin claimed that Australian tiger snake venom was as powerful as that of the cobra. In 1902, his collaborator Frank Tidswell ranked local tiger snake, brown snake and death adder venoms at the top of the <a href="http://dro.deakin.edu.au/view/DU:30068684">global toxicity table</a>. </p>
<p>Over the ensuing century, this paradox has remained: why do so few Australians die from snake bites when our serpents have the world’s most potent venoms? Why aren’t they more deadly?</p>
<h2>Deadly fear</h2>
<p>Scientific research has delivered ever-expanding knowledge about venoms, what they do, how they work, how they affect us clinically, and their comparative “potency” <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=Broad+A+and+1979">based on animal studies</a>. In response we have introduced first aid measures, <a href="https://resus.org.au/glossary/envenomation-guidelines-9-4-1-9-4-8/">guidelines</a>, effective clinical management and treatment, which in Australia forms one of the world’s best emergency health care systems.</p>
<p>In contrast, countries where snakebites cause far more deaths generally <a href="http://www.who.int/neglected_diseases/integrated_media_snakebite/en/">face challenges</a> in accessing affordable essential medicines, prevention and education options. </p>
<p>Snakes form an essential part of their ecosystems. They do not “attack” humans, mostly being shy animals, but are defensive and prefer to escape. </p>
<p>It would seem that venom potency is not a good measure of deadliness, and it may be a combination of our history, behaviour and belief that creates a <a href="http://medicalhistorymuseum.mdhs.unimelb.edu.au/exhibitions/online-exhibitions/venom-fear,-fascination-and-discovery">cultural fear</a>.</p>
<p>Without understating the potential danger posed by venomous snakes, what we offer instead is reassurance. As nearly two centuries of statistics and clinical experience suggest, most snake bites in Australia are survivable, if managed quickly, calmly and effectively. In fact, encounters with humans all too often prove deadly to the snakes themselves – a paradox that is within our power to change. </p>
<p><br></p>
<hr>
<p><em>The authors are presenting on this topic at the upcoming <a href="https://www.science.org.au/news-and-events/events/emerging-issues-science-and-society">Emerging Issues in Science and Society</a> event at Deakin University’s Downtown campus on 6 July 2017. Sponsored by the <a href="https://www.science.org.au/">Australian Academy of Science</a> and Deakin University’s <a href="http://www.deakin.edu.au/adi/our-research/research-networks/science-and-society-network">Science and Society Network</a>.</em></p>
<p><em>The event brings together scientists with humanities and social science scholars to discuss common questions from different angles. For more information on the event and to book tickets see the event’s <a href="https://www.eventbrite.com.au/e/emerging-issues-in-science-and-society-registration-33136207288">website</a>.</em></p><img src="https://counter.theconversation.com/content/79433/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ronelle Welton receives funding from the NHMRC. </span></em></p><p class="fine-print"><em><span>Peter Hobbins received an Australian Postgraduate Award to undertake his PhD on the subject of snakebite in colonial Australia, and was the 2016 Merewether Fellow at the State Library of New South Wales, which entailed research on a similar topic.</span></em></p>For over a century Australia’s venomous snakes have been counted amongst the world’s deadliest, yet human fatalities remain strikingly rare. How did our snakes develop such a fearsome reputation?Ronelle Welton, Scientist, The University of MelbournePeter Hobbins, ARC DECRA Fellow, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/728112017-02-27T15:26:48Z2017-02-27T15:26:48ZNew puff adder behaviour uncovered: it uses two ways to entice its prey<figure><img src="https://images.theconversation.com/files/157684/original/image-20170221-18624-sjmga1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Puff adders display diverse predatory strategies. This shows they have higher cognitive abilities than previously thought.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Predators use a variety of strategies to increase the odds of capturing prey. An amazing example involves the use of luring behaviours, which are aimed at increasing a predator’s foraging success by attracting potential prey to within striking range.</p>
<p>Luring behaviours result from an evolutionary adaptation referred to as <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev.es.13.110182.001125?journalCode=ecolsys.1">aggressive mimicry</a>. This typically includes a predator (the mimic), a model organism (the model), and a potential prey (the dupe). A classic example, the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.1979.tb01022.x/full">North American alligator snapping turtle</a> wriggles a pink, fleshy structure located on the floor of its mouth, which presumably resembles a worm (the model) to deceive fish (the dupes). This attracts fish and facilitates their capture by the turtle.</p>
<p>Luring also takes place on land as we found in a recent study examining the foraging behaviour of free-ranging snakes. Our <a href="http://link.springer.com/article/10.1007/s00265-016-2244-6">study</a> on the foraging in puff adders – one of Africa’s most widespread, iconic, and medically important snake species – is unique in several ways. But more of it later.</p>
<p>As part of our study we used radiotelemetry in conjunction with <a href="https://www.jstor.org/stable/4098590?seq=1#page_scan_tab_contents">fixed videography</a> to study foraging in puff adders. Fixed videography is a technique that involves continuously recording behaviours of subjects for later analysis.</p>
<p>Puff adders are ideal subjects for such studies because they use specific ambush sites where they lie in wait <a href="http://rspb.royalsocietypublishing.org/content/282/1821/20152182">for prey for extended periods</a> (sometimes days or weeks). This allowed us to setup tripod-mounted surveillance videocameras to record foraging of wild puff adders in their natural environment so that we could record natural predator-prey interactions.</p>
<p>We recorded nearly 5,000 hours of puff adder foraging behaviour in the <a href="http://www.dinokengreserve.co.za/">Dinokeng Game Reserve</a> in South Africa’s Gauteng province. It showed that to attract prey to within striking range puff adders used two techniques: they extended their tongues (lingual luring) and also waved their tails (caudal luring), apparently to mimic an invertebrate model such as a worm or caterpillar. </p>
<p>Lingual luring happened solely in response to the presence of frogs indicating that this behaviour is a frog-specific hunting technique. This suggests that puff adders can visually discriminate amphibians from small mammals, lizard, and birds – even at night when most of the hunting takes place.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/157680/original/image-20170221-18646-12z8xvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Luring is a technique adopted by puff adders to draw prey withing striking range.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Luring behaviours</h2>
<p>Luring behaviours have been reported previously in other animals. For example, in addition to the alligator snapping turtle, the <a href="http://www.jstor.org/stable/pdf/20065809.pdf">snowy egret</a> and <a href="https://www.jstor.org/stable/1565240?seq=1#page_scan_tab_contents">four</a> <a href="http://www.jstor.org/stable/1562808?seq=1#page_scan_tab_contents">species</a> of <a href="http://www.bioone.org/doi/abs/10.1670/06-016.1">semi-aquatic snakes</a> from North America are known to use their tongues to lure fish. </p>
<p>Caudal luring has also been observed in many species of <a href="http://booksandjournals.brillonline.com/content/journals/10.1163/15685381-00002997">snakes</a>, in some species of <a href="http://0-www.jstor.org.innopac.wits.ac.za/stable/1446599?seq=1#page_scan_tab_contents">lizards</a>, and the aquatic larvae of <a href="http://www.bioone.org/doi/full/10.1093/jisesa/ieu008">some dragonflies</a>.</p>
<p>But our study is the first report two lures in the same organism. It is also the first to report lingual luring in a predator foraging for terrestrial prey – all other cases involved fish as prey. And this is the first record ever of puff adders luring. </p>
<p>We are not sure what puff adders were trying to attract with their caudal-luring since there was never any potential prey in the camera’s field of view. Although we can’t provide conclusive evidence, we believe the reason for this behaviour is to lure prey because it’s been recorded in other <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8312.2008.01016.x/full">snakes</a> species.</p>
<p>Our study shows that puff adders display diverse predatory strategies and complex decision-making process to catch prey. This demonstrates that they have higher cognitive abilities than most people would expect of a snake. </p>
<p>Second, the puff adder is commonly kept in captivity for antivenin and for public display. Yet neither lingual nor caudal luring has previously been reported for the species. This shows that that even common species of snakes are often not as well-known as commonly assumed. </p>
<p>Clearly, more field studies are needed to unravel the complexity of snake behaviour. Our study illustrates the power of the radiotelemetry-videography combination as a tool for the study of snake behaviour in a natural setting.</p><img src="https://counter.theconversation.com/content/72811/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Xavier Glaudas receives funding from National Geographic. </span></em></p><p class="fine-print"><em><span>Graham Alexander receives funding from the National Research Foundation and National Geographic.</span></em></p>New research shows that puff adders use two luring techniques to attract prey within striking range.Xavier Glaudas, Post-Doctoral Fellow School of Animal, Plant and Environmental Sciences, University of the WitwatersrandGraham Alexander, Professor of Herpetology, Environmental Physiology and Physiology, Ecology and Evolution, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/714902017-01-25T19:55:08Z2017-01-25T19:55:08ZWelcome to Australia, a land of creatures out to kill you… maybe<figure><img src="https://images.theconversation.com/files/153799/original/image-20170123-30975-1knhb1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Just another of Australia's creepy crawlies... but will it kill you?</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ddimarco/13647703535/">Flickr/</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Welcome to Australia, a place that is the focus of regular reports that nearly <a href="http://www.natgeotv.com/uk/australias-deadliest-attacks">every creature is ready and waiting to pounce</a>. If it rains, it brings <a href="http://www.news.com.au/national/nsw-act/news/forbes-flooding-residents-warned-to-stay-out-of-water-due-to-presence-of-snakes/news-story/2b2d160cb68ce3a3de2c5e5e5e4a1a8a">warnings of venomous snakes</a>. If the weather is dry, then giant spiders can set up house in your <a href="http://www.dailymail.co.uk/news/article-3200356/Massive-spider-gives-homeowner-shock-covering-electricity-meter-HUNDREDS-creepy-babies.html">power box</a>.</p>
<p>But as Australia prepares once again to welcome many new citizens this Australia Day, it seems appropriate to take a closer look at how deadly our creatures really are.</p>
<p>There is no doubt Australia harbours <a href="https://www.healthdirect.gov.au/bites-and-stings">venomous animals and encounters</a> that can be traumatic and need a rapid emergency response.</p>
<p>We must we careful not to understate the impact of any encounters with venomous animals on families and the sufferers themselves. Nor must we play down the highly specialised management, effective treatment and medical care required.</p>
<p>But is this reputation of a land of deadly and aggressive creatures well founded?</p>
<h2>Detail in the data</h2>
<p>My colleagues and I recently published a review of hospital admissions and deaths caused by venomous animals in the <a href="http://onlinelibrary.wiley.com/wol1/doi/10.1111/imj.13297/abstract">Internal Medical Journal</a>.</p>
<p>We sourced data from 2001-2013 from national hospital admissions and national coronial information, which showed more than 42,000 hospitalisations from venomous sting or bites. Most – not all – are shown in the graph, below.</p>
<iframe src="https://datawrapper.dwcdn.net/UINJU/1/" frameborder="0" allowtransparency="true" allowfullscreen="allowfullscreen" webkitallowfullscreen="webkitallowfullscreen" mozallowfullscreen="mozallowfullscreen" oallowfullscreen="oallowfullscreen" msallowfullscreen="msallowfullscreen" width="100%" height="350"></iframe>
<p>Over the 12 years that’s an average 3,500 people admitted to hospital every year for a venom-related injury. This can be loosely averaged 0.01% of the Australian population per year, or roughly one in 10,000 Australians.</p>
<p>Allergy or anaphylaxis from insect stings such as bees or wasps were responsible for about one-third (33%) of hospital admissions, followed by spider bites (30%) and snake bites (15%).</p>
<iframe src="https://datawrapper.dwcdn.net/PJ4fJ/1/" frameborder="0" allowtransparency="true" allowfullscreen="allowfullscreen" webkitallowfullscreen="webkitallowfullscreen" mozallowfullscreen="mozallowfullscreen" oallowfullscreen="oallowfullscreen" msallowfullscreen="msallowfullscreen" width="100%" height="380"></iframe>
<p>Over the 12 years, 64 people were killed by a venomous sting or bite, with more than half of these (34) caused by an allergic reaction to an insect bite that brought on anaphylactic shock.</p>
<p>Of these, 27 deaths were the result of a bee or wasp sting, with only one case of a beekeeper being killed. Anaphylaxis to tick and ant bites combined caused five deaths, the box jellyfish caused three deaths and two deaths were from an unidentified insect. </p>
<p>Given there are 140 species of land snakes in Australia, snake bite fatalities are very rare, at 27 for the study period. To put that in perspective, the World Health Organization estimates that <a href="http://www.who.int/mediacentre/factsheets/fs337/en/">at least 100,000 people die</a> from snake bite globally each year. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/153813/original/image-20170123-8062-p344v0.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"></a>
<figcaption>
<span class="caption">The red belly black snake is not as nasty as it looks.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/derekarlanyoung/5153325876/">Flickr/Derek A Young</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>While it’s natural to be frightened of snakes, the reality is the number of deaths from snake bites in Australia is very small. In the same time frame, for example, figures from the National Coronial Information System (<a href="http://www.ncis.org.au/">NCIS</a>) show nearly 5,000 people died from drowning and 1,000 from burns in Australia. </p>
<p>Nevertheless, snake bites do hold the crown as the most common cause of death, with nearly twice as many deaths per hospital admission than any other venomous injury, making snakebite one of the most important issues to address.</p>
<h2>Deadly creatures elsewhere</h2>
<p>Understandably, living in a country with creatures that can potentially kill us is a daunting prospect. As you can see from the figures, though, they don’t kill as many people as you might think and other countries have their own potentially deadly creatures.</p>
<p>In the United Kingdom there are reports of deaths or injuries from <a href="http://www.bbc.com/news/uk-england-devon-37825677">bees</a>, <a href="http://www.independent.co.uk/news/uk/home-news/grandmother-dies-after-being-bitten-by-false-widow-spider-9851990.html">widow spiders</a>, <a href="http://www.bbc.com/news/uk-scotland-36922987">jellyfish</a> and <a href="http://www.mirror.co.uk/news/uk-news/boy-3-bitten-snake-uk-8106059">adder snakes</a>.</p>
<p>The continent of America has a menagerie of reptilian assassins such as vipers, and its mammals also pack a punch, with reports of attacks from <a href="http://www.abc.net.au/news/2016-11-20/63yo-us-woman-survives-bear-attack/8040478">bears</a>, <a href="http://www.nbcnews.com/id/35913715/ns/us_news-life/t/fatal-wolf-attack-unnerves-alaska-village/#.WIVqpbb5hVo">wolves</a> and <a href="http://edition.cnn.com/2016/06/18/us/colorado-mountain-lion-attack/">mountain lions</a>.</p>
<p>A sturdy Australian would surely quake at the thought of being faced with an offensive grizzly, with no amount of Crocodile Dundee-esk buffalo hypnotism techniques going to get us through that encounter.</p>
<p>Sure Australia also has sharks and crocodiles, but it’s important to note that the majority of our critters do not come after you.</p>
<h2>Minimising the minimal risk</h2>
<p>Our report, while giving a broad overview of envenoming trends in Australia, does raise more questions than it answers. Questions such as: who is most at risk and how can we support them? Do we need more localised guidelines? And how do we maintain knowledge for such a rare injury?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=562&fit=crop&dpr=1 754w, https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=562&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/153814/original/image-20170123-8062-16flnit.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=562&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">No one died from a spider bite during the 12 years of our study.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/corrieb/4505369450/">Flickr/Corrie Barklimore</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This work seeks to initiate new conversations in regard to potential gaps in knowledge in both the public and health domains, and find solutions. We’re currently seeking funding to continue this research.</p>
<p>From an individual or national public health perspective, we can’t make informed decisions until we have a much clearer picture of what’s going on. The big question is how can we manage this coexistence with the creatures around us, without being detrimental to people and the creatures themselves. </p>
<p>It comes down to understanding, appreciating and respecting the amazing diversity nature has provided us. We need to learn about prevention methods and understand correct first aid.</p>
<p>This, together with the ongoing research and improvements in clinical care and the accessibility, affordability, effective management and treatment of bites and stings in Australia, actually make it one of the safest places in the world, and certainly not one of the deadliest.</p><img src="https://counter.theconversation.com/content/71490/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ronelle Welton receives funding from NHMRC </span></em></p>Australia’s snakes, spiders and other venomous critters tend to strike fear in many people. But is Australia’s reputation as a nation of deadly creatures deserved?Ronelle Welton, Research Fellow, Department of Pharmacology, Faculty and Medicine, Dentistry and Health Sciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/661542016-10-13T13:28:54Z2016-10-13T13:28:54ZWhy we should bother saving Britain’s only venomous snake<figure><img src="https://images.theconversation.com/files/141507/original/image-20161012-16206-t4jx0h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://tellhicks.weebly.com/">Tell Hicks</a></span></figcaption></figure><p>The adder, <em>Vipera berus</em>, was one of the first venomous snakes <a href="http://snakesarelong.blogspot.co.uk/2015/05/linnaean-snakes-part-i.html">formally named by Linnaeus</a> in 1758. It is the <a href="http://booksandjournals.brillonline.com/content/journals/10.1163/156853803322763918">most northerly</a> occurring snake, and one of the <a href="https://www.vapaguide.info/cgi-bin/WebObjects/vapaGuide.woa/3/wa/getImage?id=op_1244204871966">most widely distributed species</a>, found everywhere from the UK to Sakhalin island, Russia. It is also the only venomous snake in Great Britain. Despite this, centuries of bad press for the adder, ranging from <a href="http://adder.narrs.org.uk/folklore.php">folklore to Shakespeare</a>, have left its mark. </p>
<p>You may be forgiven for thinking that adders are becoming a serious problem in the UK after several <a href="http://www.express.co.uk/news/nature/697048/pet-warning-dog-dies-snake-bite-adder-toddler-bitten-venomous-RSPCA-wildlife-trust">high-profile headlines</a> this summer. While not as sensationalist as those relating to <a href="http://www.dailystar.co.uk/news/latest-news/497368/Footie-Star-Killer-spider-arm-false-widow-deadly-wrexham">false widow spiders</a>, there certainly seems to have been a spike in the number of adder bites, perhaps encouraged by periods of hot weather <a href="https://blog.metoffice.gov.uk/2016/09/29/september-warmth-in-the-uk/">as late as September</a>. Given that this may be a more regular feature <a href="https://www.theguardian.com/environment/2016/sep/16/arctic-sea-ice-shrinks-to-second-lowest-level-ever-recorded">as climate change takes hold</a>, should we be worried about the abundance of the adder? </p>
<p>The answer is yes, but not because of an increase, rather because the adder is in widespread decline, particularly in the UK. Despite being described as of “least concern” in the <a href="http://www.iucnredlist.org/details/157248/1">IUCN red list of threatened species</a>, recent reports from the <a href="http://www.ravon.nl/Portals/0/PDFx/Delft%20et%20al,%202015.%20De%20adder%20in%20Nederland.%20Verspreiding,%20status%20en%20trend.pdf">Netherlands</a>, <a href="http://publications.naturalengland.org.uk/publication/142003">the UK</a> and <a href="http://link.springer.com/article/10.1007%2Fs10592-008-9580-7">other parts of western Europe</a> show drastic regional drops in numbers. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/141599/original/image-20161013-31310-1plmkm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The common European adder.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-417816811/stock-photo-common-european-adder.html?src=hIZv4Z9c8zrt4cS_3uc5sg-1-53">Svoboad Pavel/www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>The fall in adder numbers is frequently attributed to the same suite of factors: disappearance of their habitats, increasing isolation and a decrease in the quality of the remaining habitat resulting from over-zealous management, an increase in disturbance from recreation on prime adder habitats, and deliberate persecution. But it’s not just that: a lack of attention to species that continue to be widespread but are declining in number is a <a href="http://www.discoverwildlife.com/blog/raising-awareness-widespread-species-declines">wider conservation problem</a>, not least because the occasional encounter with a charismatic animal tends to leave a lasting impression, making it appear more common than it really is.</p>
<h2>The uncommon adder</h2>
<p>Adders have had some level of protection in the UK for 15 years: their <a href="http://jncc.defra.gov.uk/page-1377">trade was banned</a> in England and Wales in 1981, while additional amendments in 1991 – <a href="http://jncc.defra.gov.uk/page-3148">and 2004 in Scotland</a> – <a href="http://jncc.defra.gov.uk/page-1377">stopped intentional killing and injuring</a> of them. European legislation also <a href="http://naturenet.net/law/herps.html">covers the adder</a>, and yet they have continued to decline to the point that they are now extinct in some counties, such as Warwickshire and Nottinghamshire, and only found in small isolated pockets of suitable habitat in others. Even populations which are hanging on are smaller than they were <a href="http://publications.naturalengland.org.uk/publication/142003">12 years ago</a>.</p>
<p>Somehow, management that is benefiting other reptiles is not working for the adder. While it may be tempting to attribute the decline to <a href="http://www.linnaeus.uu.se/online/questions/animals_1.html">poor public image</a>, it is more likely that the adder is much more fussy about its requirements than other species. They are a species on the edge in more ways than one, preferring to occupy the boundaries between scrub – which they use for cover – and more open heathland or chalk grassland, which offers foraging and basking opportunities. They prefer mid-successional vegetation stages that, if left to their own devices, would gradually turn into woodland and therefore require active management to keep them at the right stage. In short, a lot needs to be right if a habitat is to play host to a healthy adder population. </p>
<p>Moreover, access to a suitable place to sit out winter frosts is essential, and destruction of such shelters can rapidly eliminate an existing population. Meanwhile, many areas which formerly did, or could, support adder populations are managed with other species in mind, using practices which are directly or indirectly detrimental to adders. <a href="https://rspb.org.uk/news/404053-our-uplands-are-becoming-a-burning-issue">Increasingly regular burning of moorland</a> for grouse management is one obvious example, but even the <a href="http://www.snh.gov.uk/docs/A1925163.pdf">maintenance of a short and open sward</a> to favour orchids can be counterproductive for adders.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/141618/original/image-20161013-31319-dh27vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The distinct pattern of the adder makes it stand out from other species.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-316824392/stock-photo-european-adder-vipera-berus-pattern.html?src=Zwl4MnTG9ZK9zBBRQ42NaQ-1-1">Matteo photos/www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>But apart from the handful of experts and enthusiasts <a href="http://www.arguk.org/get-involved/events/2-the-vanishing-viper-priorities-for-adder-conservation-a-national-meeting">engaged in keeping the adder alive</a>, does anyone else care? UK conservation bodies are currently constructing a national “Red List” and the adder is likely to be listed as at least “vulnerable” to extinction. This, along with other forthcoming reports, may finally make the adder a priority species, one that needs to be considered when designating protected areas and in designing their management plans. </p>
<p>For those less than enamoured by the thought of an adder in their midst, bear in mind that an adder bite can be treated effectively by using anti-venom. Ultimately, we all need to cultivate a <a href="https://www.cam.ac.uk/research/news/science-is-a-risky-quiz-ness-a-new-study-aims-to-assess-how-we-perceive-risks">more informed attitude to risk</a>. The <a href="http://www.newstatesman.com/sci-tech/2014/06/no-one-will-die-snakebite-britain-summer-why">last recorded human death</a> in the UK from an adder bite was in 1975, and between 2004 to 2010, there were only 510 snake bite enquiries to the <a href="http://www.npis.org/">UK national poisons information service</a>. </p>
<p>Interestingly, bites by the adder accounted for only <a href="http://patient.info/doctor/snake-bites">52% of these cases</a>, with bites by exotic species presumably being kept as captive animals accounting for the largest proportion of the remaining bites. On the other hand, <a href="http://content.digital.nhs.uk/catalogue/PUB06338/hes-on-dog-bite.pdf">an NHS report</a> on the number of people bitten by dogs shows that in 2009-2010 alone, dog bites were responsible for 5,914 hospital admissions in England, with at least 21 fatalities during the last 10 years. Now who’s the snake in the grass?</p><img src="https://counter.theconversation.com/content/66154/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anita Malhotra 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>We should be worried about the adder – but not because it’s dangerous.Anita Malhotra, Senior Lecturer in Ecology and Evolutionary Genetics, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.