tag:theconversation.com,2011:/us/topics/frog-15826/articlesFrog – The Conversation2023-12-27T20:26:20Ztag:theconversation.com,2011:article/2139762023-12-27T20:26:20Z2023-12-27T20:26:20Z‘Foul and loathsome’ or jewels of the natural world? The complicated history of human-frog relations<figure><img src="https://images.theconversation.com/files/549226/original/file-20230920-27-n3caid.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C5176%2C3437&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>When was the last time you saw a frog? Perhaps you came across one in your garden and wondered at its little hands, glossy skin and what looked very much like a contented smile.</p>
<p>Maybe you regularly see them on Instagram or TikTok, where “frog accounts” have proliferated in recent years. People share adorable cartoon frogs, coo over crocheted frogs or go gaga for <a href="https://www.tiktok.com/@frog._.dad/video/7246026248227491099?lang=en&q=frog&t=1695172051974">frogs dressed in cute hats</a>. </p>
<p>In fact, our fascination with frogs isn’t new. As <a href="https://www.ingentaconnect.com/content/whp/eh/2022/00000028/00000001/art00007">our research has found</a>, the history of human-frog relations is long and complicated – and not all of it is nice.</p>
<p><div data-react-class="TiktokEmbed" data-react-props="{"url":"https://www.tiktok.com/@frog._.dad/video/7246026248227491099?lang=en\u0026q=frog\u0026t=1695172051974"}"></div></p>
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Read more:
<a href="https://theconversation.com/australian-frogs-are-dying-en-masse-again-and-we-need-your-help-to-find-out-why-184255">Australian frogs are dying en masse again, and we need your help to find out why</a>
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<h2>Why we love frogs</h2>
<p>There is a rich history of people <em>really</em> loving frogs. </p>
<p>This is interesting, because many people much prefer mammals and birds over reptiles and amphibians. </p>
<p>But the frog is an exception – for a lot of reasons. People tend to be attracted to baby-like faces. Many species of frog have the large eyes characteristic of young animals, humans included. </p>
<p>Having no teeth and no sharp claws, they also do not seem to be immediately threatening, while many of them have beautiful skin colouring and some are improbably tiny. </p>
<p>Frogs are truly among the jewels of the natural world, unlike toads which – with their more mundane colours and “warty skins” – do not usually inspire the same sense of enchantment. </p>
<p>Their beauty connects us to the wider riches of a vibrant nature hidden from most people’s sight in the dense rainforests of the tropical regions.</p>
<p>And they also connect us to nature in our own backyards. At certain times of the year, they spontaneously appear in our gardens and ponds. They can feel like special visitors from the natural world.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/Cnr90omjqsE","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Dissecting human feelings for frogs</h2>
<p>Yet relationships between people and frogs haven’t always been so positive. In fact, frogs occupy complicated places across cultures all over the world. </p>
<p>In the Western tradition, the legacy of biblical and classical sources was both negative and longstanding. </p>
<p>References to frogs in the Bible rendered them the instrument of divine anger as a swarming plague.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An etching from the late 1700s shows a plague of frogs." src="https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=597&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=597&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555125/original/file-20231022-15-6uzo15.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=597&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An etching from the late 1700s shows a plague of frogs.</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/mrhcn8sj">Wellcome Collection</a></span>
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<p>Frogs challenged early modern zoological taxonomies, moving between classification as serpent, insect or reptile.</p>
<p>Perhaps their resistance to easy placement by humans explains the strong emotional language about them used by Swedish naturalist (and “father of modern taxonomy”) Carl Linnaeus.</p>
<p>When he considered the Amphibia in his 1758 <a href="https://www.biodiversitylibrary.org/item/10277#page/216/mode/1up"><em>Systema Naturae</em></a>, he <a href="https://web.archive.org/web/20131111000622/http://si-pddr.si.edu/dspace/bitstream/10088/8238/1/SHIS_100.pdf">noted</a>:</p>
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<p>These foul and loathsome animals are abhorrent because of their cold body, pale colour, cartilaginous skeleton, filthy skin, fierce aspect, calculating eye, offensive smell, harsh voice, squalid habitation, and terrible venom.</p>
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<p>In modern science, they sit in a branch of zoology, herpetology, that brings frogs together as “creeping animals” with snakes and lizards.</p>
<p>Frogs have also (or perhaps consequently) suffered in the service of science since at least the eighteenth century because it seemed to be possible to easily replicate experiments across multiple frog specimens. </p>
<p>Frogs were particularly crucial to the study of muscles and nerves. This led to ever more violent encounters between experimenters and frog bodies. Italian scientist Luigi Galvani, for example, did experiments in the late 18th century on legs of frogs to investigate what he thought of as “<a href="https://www.historytoday.com/archive/months-past/galvani-discovers-animal-electricity">animal electricity</a>”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Legs of dissected frogs, and various metallic apparatus used to measure what was thought to be electricity flowing in animals" src="https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557188/original/file-20231101-21-hhtsxe.png?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"></a>
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<span class="caption">Scientist Luigi Galvani’s 18th-century diagrams of dissected frog legs and various metallic apparatus he used to measure what was thought to be electricity flowing in animals.</span>
<span class="attribution"><a class="source" href="https://www.loc.gov/resource/cph.3b41495/">Library of Congress</a></span>
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<p>In this sense, frogs were valued as significant scientific objects, their value lying in their flesh, their nervous systems, rather than in their status as living, feeling beings in the world. </p>
<p>In time, experiments with frogs moved beyond the laboratory into the classroom. In the 1930s, schoolchildren were expected to find frogs and bring them to school for dissection in biology classes. </p>
<p>This practice was, however, somewhat controversial, with opponents <a href="https://www.ingentaconnect.com/content/whp/eh/2022/00000028/00000001/art00007">expressing sentimental attachment</a> to frogs and concerns that such animal cruelty would lead to barbarism.</p>
<h2>Recognising the fragility of frogs</h2>
<p>So, our relationship with frogs is complicated. From the frogs of <a href="https://aesopsfables.org/C11_aesops_fables_about_frogs.html">Aesop’s Fables</a> to the meme <a href="https://en.wikipedia.org/wiki/Pepe_the_Frog">Pepe the Frog</a>, we have projected our own feelings and frustrations onto frogs, and exploited them for science and education. </p>
<p>Frogs have also borne the brunt of our failures as environmental stewards. </p>
<p>By 1990, the world was seeing a global pattern of decline in frog populations due to <a href="https://www.science.org/doi/10.1126/science.1103538">destruction and degradation of habitat for agriculture and logging</a>, as well as a <a href="https://theconversation.com/deadly-frog-fungus-has-wiped-out-90-species-and-threatens-hundreds-more-113846">global amphibian pandemic caused by the chytrid fungus</a>.</p>
<p>Climate change is also making life hard for many species. In 2022, over 40% of amphibian species (of which frogs and toads are by far the largest group) were <a href="https://downloads.ctfassets.net/tftu3vbfu92u/7C9C6rtfnonRArYQYsFzHW/0cf85bd3ff9084907cc3cbf14aed3a23/SOTWA_-_final_10.3.23.pdf">threatened with extinction</a>. Their vulnerability has seen the frog – especially the red-eyed tree frog – become a symbol for the environment more generally.</p>
<p>So we should delight in frogs and marvel at how beautiful and special they are while we still can, and consider how we might <a href="https://theconversation.com/we-name-the-26-australian-frogs-at-greatest-risk-of-extinction-by-2040-and-how-to-save-them-166339">help save them</a>. </p>
<p>Something to reflect on next time you are lucky enough to spot a frog.</p>
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Read more:
<a href="https://theconversation.com/australians-recorded-frog-calls-on-their-smartphones-after-the-bushfires-and-the-results-are-remarkable-146578">Australians recorded frog calls on their smartphones after the bushfires – and the results are remarkable</a>
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<img src="https://counter.theconversation.com/content/213976/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Susan Broomhall receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Andrea Gaynor receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Andy Flack 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>There is a rich history of people really loving frogs. But the history of human-frog relations is long and complicated – and not all of it is nice.Susan Broomhall, Director, Gender and Women's History Research Centre, Australian Catholic UniversityAndrea Gaynor, Professor of History, The University of Western AustraliaAndy Flack, Senior Lecturer in Modern and Environmental History, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1576332021-03-28T08:49:48Z2021-03-28T08:49:48ZWhat Madagascar’s amazing mini creatures tell us about evolution<figure><img src="https://images.theconversation.com/files/392048/original/file-20210327-21-1lcbjx6.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Brookesia tedi, described in 2019, is one of the smallest chameleons, and indeed one of the smallest amniote vertebrates, on earth. </span> <span class="attribution"><span class="source">Mark D. Scherz</span></span></figcaption></figure><p><em>Madagascar has many “mini” creatures. These include a recently discovered group of miniaturised frogs as well as the discovery earlier this year of the <a href="https://www.bbc.com/news/world-africa-55945948">smallest reptile on earth</a> – the Brookesia nana, or nano-chameleon, which is the size of a paperclip. Moina Spooner, from The Conversation Africa, asked Dr Mark D. Scherz, an amphibian and reptile specialist who focuses on Madagascar, to explain what causes these animals to miniaturise.</em></p>
<h2>Which miniaturised species have been discovered recently?</h2>
<p>Madagascar is famous for its small animals; the mouse lemurs, the smallest primates on earth, for instance, are widely known. There’s also growing awareness that Madagascar is home to a variety of other uniquely miniaturised animals, especially chameleons and frogs. In those groups, researchers have discovered large numbers of tiny species in recent years. </p>
<p>In 2017, researchers described 26 species of <em>Stumpffia</em> – a group of frogs – the smallest of which is not even 1cm long at adult body size. It is one of the smallest frogs in the world. </p>
<figure class="align-center ">
<img alt="Frog on a leaf with a human finger next to it to show relative size" src="https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=571&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=571&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391646/original/file-20210325-15-1lsr12z.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=571&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">Stumpffia yanniki, a moderately small narrow-mouthed frog species from northern Madagascar, described in 2017.</span>
<span class="attribution"><span class="source">Mark D. Scherz</span></span>
</figcaption>
</figure>
<p>Then, in 2019, my colleagues and I showed that several different groups of cophyline microhylids – a group of narrow-mouthed frogs that are only found in Madagascar – have become miniaturised independently. One group of these was an entirely new genus. We gave them the fitting name “<em>Mini</em>”, with the three species <em>Mini mum</em>, <em>Mini scule</em>, and <em>Mini ature</em>. </p>
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<em>
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Read more:
<a href="https://theconversation.com/meet-the-mini-frogs-of-madagascar-the-new-species-weve-discovered-113946">Meet the mini frogs of Madagascar -- the new species we've discovered</a>
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<p>We have also found some new tiny chameleons. In 2019, we described <a href="https://zse.pensoft.net/article/32818/"><em>Brookesia tedi</em></a>, a chameleon that reaches a total length of just 32mm. And then in early 2021, we described <a href="https://www.nature.com/articles/s41598-020-80955-1"><em>Brookesia nana</em></a>, the smallest chameleon, which has adult males of just 21.6mm total length, and females 28.9mm.</p>
<h2>Why have they evolved to be so small?</h2>
<p>There are probably many different reasons why these animals have evolved to be so small. For instance, it might be possible for them to exploit new resources that weren’t previously available to them. This may be new food sources, or exploring the space between leaves and tree roots that is inaccessible to larger animals. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391413/original/file-20210324-23-pwx674.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">Stumpffia madagascariensis is a tiny leaf-litter dwelling frog from northern Madagascar.</span>
<span class="attribution"><span class="source">Mark D. Scherz</span></span>
</figcaption>
</figure>
<p>It could also be driven by competition with other, similar species. Species may diverge into different size categories to partition their resources and avoid direct competition.</p>
<p>In many cases, there may be no strong or single selective force that is driving the miniaturisation at all, but instead it could simply be a process of random change in the population, which occurs in all organisms over time. This is further driven by population bottlenecks as the smaller and smaller animals get cut off from other populations. </p>
<p>The simple answer is that we just don’t know yet in any of the cases, and it is likely that in most it is a combination of factors. We are much better able to say what the correlates of miniaturisation are – that is, the suite of features, behaviours, and ecologies that accompany miniaturisation – than the causes.</p>
<h2>Does Madagascar have an unusually high number of mini creatures?</h2>
<p>Speaking only of reptiles and amphibians, maybe, but it is hard to say for sure. South-East Asia has <a href="https://www.nationalgeographic.com/animals/article/120111-smallest-frogs-vertebrates-new-species-science-animals">a massive diversity of miniaturised frogs</a>, for instance, but whether the number of major miniaturisation events in that region is greater or less than in Madagascar is difficult to say for sure. </p>
<p>The same goes for Central and South America, where there are plenty of tiny amphibians and reptiles, including salamanders, frogs and lizards. </p>
<p>Ultimately, even though Madagascar may not be the world champion in terms of the number of miniaturised reptiles and amphibians, I think it does stand out as an exceptionally interesting place in which to study their evolution, and we are only just starting to scratch the surface of this.</p>
<h2>What does their tiny size tell us about evolutionary processes?</h2>
<p>This is the question I find the most exciting. From miniaturisation we can learn all kinds of interesting things about physiology, evolution and biomechanics – how organisms move and function.</p>
<p>For instance, there appears to be a pattern where the evolution of miniaturisation is associated with changes in ecology. Almost all miniaturised frogs in Madagascar are terrestrial, irrespective of whether their ancestors were terrestrial arboreal (living in trees). The only conditions under which miniaturised frogs have remained arboreal throughout miniaturisation has been when they reproduce in the water cavities at the base of certain plants’ leaves, such as the <em>Pandanus</em> plant.</p>
<p>We have also learned that the microhylid frogs of Madagascar have mostly miniaturised by retaining juvenile-like characteristics, known as paedomorphosis. For instance, they all have relatively large heads and eyes for their body sizes.</p>
<p>But one species, <em>Rhombophryne proportionalis</em>, has apparently miniaturised by proportional dwarfism. It has the approximate proportions of a non-miniaturised Rhombophryne. So, although paedomorphosis may be the typical way that Malagasy frogs miniaturise, it is by no means the only way that they can miniaturise. </p>
<p>Another particularly interesting finding is that miniaturisation has apparently evolved again and again in different lineages. This was already evident in frogs at the global scale (there are miniaturised frog lineages throughout the tropics). But one group of frogs in Madagascar has done this five or more times alone. This tells us that the evolution of miniaturisation can occur frequently and may be advantageous under certain circumstances. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391412/original/file-20210324-23-hbq4me.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">Brookesia tuberculata from northern Madagascar was for some time held to be the smallest species of chameleon, but has been repeatedly upstaged. Its real claim to fame, however, is that it has by far the largest hemipenis relative to its body length of any chameleon.</span>
<span class="attribution"><span class="source">Mark D. Scherz</span></span>
</figcaption>
</figure>
<p>From our work on miniaturised chameleons, we have also found that, as these lizards shrink, their genitals increase in relative size. We think that this is because the females are larger than the males. Because the male genitals must couple with those of the females for successful reproduction, and because the female is not as small as the male, the male’s genitals are constrained to remain proportional to the size of the female, even while his body size evolves to be smaller.</p>
<p>There are hundreds of open questions in the field of tiny vertebrate studies. We are just beginning to understand how widespread and common this trait is, how many species have done it, and how many miniaturised species remain undescribed. There is a whole miniature frontier of interesting research to be had among these tiny vertebrates, and I, for one, am excited to see what we discover next.</p><img src="https://counter.theconversation.com/content/157633/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark D. Scherz 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>Madagascar stands out as an exceptionally interesting place in which to study the evolution of “mini” creatures. And we are only just starting to scratch the surface of this.Mark D. Scherz, Research scientist, Technical University BraunschweigLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1215282019-08-27T12:59:34Z2019-08-27T12:59:34ZWhat is the smallest animal ever?<figure><img src="https://images.theconversation.com/files/289135/original/file-20190822-170927-hfk4mc.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The world's smallest frog can fit on a dime.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Paratype_of_Paedophryne_amauensis_(LSUMZ_95004).png">E.N. Rittmeyer et al. (2012)</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What is the smallest animal ever? – Peter, age 9, Brookline, Massachusetts</strong></p>
</blockquote>
<hr>
<p>The biggest animal in the world is easy to see, if you know where to look. Living in every ocean except the Arctic, the blue whale is the <a href="https://www.natgeokids.com/nz/discover/animals/sea-life/10-blue-whale-facts/">largest animal on Earth</a> — weighing as much as 200 tons with a heartbeat that can be heard up to two miles away.</p>
<p>But the smallest animal in the world? Even if you knew where to look, could you see it? To track down the tiniest creature, scientists had to first decide what they were looking for and then, where they might find it. The first question – “What is an animal?” – is something that <a href="https://doi.org/10.1038/news060130-4">scientists have debated</a> for centuries.</p>
<p>I am an <a href="https://cvhs.okstate.edu/veterinary-medical-hospital/small-animal/avian-exotics-and-zoo-medicine/di-girolamo-publications.html">exotic animal veterinarian</a> especially fascinated by these types of questions.</p>
<h2>What is an animal?</h2>
<p>In the language of science, an animal is an organism made of multiple cells. Cells are the building blocks of all living things – a human body, for example, is made up of trillions of cells. Some organisms, like bacteria, are made of just one cell. They are not considered animals. </p>
<p>The simplest single-celled creatures – including bacteria – are called prokaryotes. They don’t contain a nucleus, the feature that acts like the main control center for a cell. More complex cells have an enclosed nucleus. They are called eukaryotes. Anything from an earthworm to a zebra or you are all eukaryotes and all are considered animals.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289168/original/file-20190823-170910-1wt2b01.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The blue whale is the largest animal in the world. But what is the smallest?</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=17942391">NOAA Photo Library</a></span>
</figcaption>
</figure>
<h2>If it can’t be seen, does that count?</h2>
<p>Based on this definition, an animal can be something so small that it’s not possible to see without a microscope. This is definitely not something that you would probably call an “animal.” A recent discovery is an organism that is invisible to the eye, a parasitic jellyfish called Myxozoa. They are very small and reaching barely 20 micrometers. Stretched out end to end, it would take more than 1,000 of these creatures to equal 1 inch.</p>
<p>Probably the smallest of these parasitic jellyfish is <em>Myxobolus shekel</em>, which <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4900514/">is no more than 8.5 micrometers when fully grown</a>.</p>
<p>This species was described in 2011, so is pretty new. So is the decision that Myxozoa are related to jellyfish, which scientists agreed on in 2015. The discovery of these types of jellyfish <a href="https://www.ncbi.nlm.nih.gov/pubmed/27330981">occur once in a while</a>, so it is possible that a new and even smaller animal will be discovered in the future.</p>
<h2>The process of elimination</h2>
<p>Let’s assume that you’re looking for the smallest “animal” that is visible to the human eye. Some invertebrates, or animals without a backbone, and other smaller organisms are not visible to the human eye. What is left are vertebrates, animals with backbones that include mammals such as a dog, a whale or you, reptiles such as snakes or crocodiles, birds, fishes and amphibians. <a href="https://www.nationalgeographic.com/animals/amphibians/">Most amphibians</a>, like frogs, are born in water and breathe with gills until they mature, when they develop lungs and an ability to live on land. </p>
<p>In this group of animals, it is the amphibians that win the prize for the smallest animal known, for the moment.</p>
<p>Scientists traveled to New Guinea, the second largest island in the world, to study the the island’s wildlife. This is where they found the smallest known type of frog called <em>Paedophryne amauensis</em>. The body length of an average adult is reported at less than 8 mm, <a href="https://www.nationalgeographic.com/news/2012/1/120111-smallest-frogs-vertebrates-new-species-science-animals/">about the size of a pea</a>. When it was discovered in 2009, it was immediately awarded the title of “<a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029797">world’s smallest vertebrate</a>.”</p>
<p>The smallest animal is a question that scientists have debated for many years. Don’t worry. The nature of science means the answers will keep changing as researchers make new discoveries. Maybe a smaller vertebrate will be discovered in a quiet forest, on an exotic island, at the bottom of a canyon or in the dark abyss of the ocean. Scientists will keep looking.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>.</em>
<em>Please tell us your name, age and the city where you live. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/121528/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicola Di Girolamo does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Scientists have identified the world’s smallest animal – for now. It could be possible smaller creatures exist that have not yet been discovered.Nicola Di Girolamo, Associate Professor of Veterinary Clinical Sciences, Oklahoma State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/699142016-12-11T06:18:04Z2016-12-11T06:18:04ZHow we learned to listen to elusive, threatened frogs<figure><img src="https://images.theconversation.com/files/148908/original/image-20161206-25738-16zp2hx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Cape peninsula moss frog is smaller than 20mm and is, therefore, hard to monitor.</span> <span class="attribution"><span class="source">Francois Becker</span></span></figcaption></figure><p>Scientists the world over have a frog problem: we have little idea of how many frogs there are in each species in the world. This means that we are unable to predict how many there will be in the future due, for example, to the effects of climate change.</p>
<p>There have been very few studies recording the size of amphibian populations. So those of us studying amphibians have very little with which to work. What we do know is that many frogs are under threat mostly from habitat change, but also from disease. In southern Africa they are particularly vulnerable to <a href="http://john.measey.com/media/545057e1-8025-4abd-9aa7-3a90f470dd01/NgmUbw/PDFs/Measey_2011_Ensuring.pdf">invasive species</a>.</p>
<p>Male frogs advertise their presence with species specific mating calls. Determining their presence has traditionally entailed listening for these calls. If you want to know how many frogs are calling, then stand with your hands behind your ears and try to count all the animals you hear. It sounds simple, but it’s not that easy. I’ve tried. </p>
<p>Listening to 10 calling animals is taxing. More than 10 and it’s possible to get muddled. Choruses of over 50 sound like noise. </p>
<p>Luckily the revolution in digital media has helped those of us studying amphibians. We’re able to monitor vocalising species and record a large number of sounds from the environment. Automated computer software, like voice recognition on smart phones, can then pick out particular species from their calls. Acoustic monitoring is ideal for monitoring the abundance of a species over time, as it has minimal impact on the species being monitored. </p>
<p>But what then? Interpreting the number of calls is problematic for several reasons. First and foremost is the fact that the area a microphone listens to is not defined. The vagaries of the acoustic environment mean that the slightest wind, or even a change in humidity, can affect the distance over which sound propagates. This means that microphones listen to different areas every time they record.</p>
<p>Recently <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12810/full">published research</a> by my colleagues and I could change this. It provides a methodology for acoustic monitoring that calculates the area listened to by an array of microphones, as well as estimating the number of calls made in that area. This has important implications for acoustic monitoring – and for attempts to catalogue just how many frogs are “ribbiting” around us. </p>
<h2>A new methodology</h2>
<p>We used microphones to monitor the Cape peninsula moss frog (<em>Arthroleptella lightfooti</em>) in Table Mountain National Park, South Africa. These frogs are endemic to the area and occur nowhere else on the planet. They are listed as “<a href="http://www.iucnredlist.org/details/58061/0">Near Threatened</a>” on the IUCN list of threatened species. Any data we can glean will contribute to their conservation. </p>
<p>We used an array of six microphones to monitor populations of Cape peninsula moss frogs over their winter breeding season from May to October. </p>
<p>Researchers have previously used time of arrival of sound at each microphone in an array to determine the position <a href="https://youtu.be/JTYFYtZJXro">of calling animals</a>. </p>
<p>We used a novel statistical technique developed by co-author statisticians Stevenson and Borchers (<a href="http://john.measey.com/ascr">Spatial Capture Recapture: SCR</a>) to analyse the automated call data. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/148901/original/image-20161206-25721-ysekwe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Listening for calls of the endangered Arthroleptella subvoce to monitor its abundance in the Groot Winterhoek Wilderness Area, South Africa.</span>
<span class="attribution"><span class="source">John Measey</span></span>
</figcaption>
</figure>
<p>The analysis takes into account both microphones which hear calls and those which don’t hear calls, as well as the distance between microphones to build up an estimate of the number of calls and the <a href="https://youtu.be/JTYFYtZJXro">area from which the calls come</a>. For an encore, the statisticians combined the information from time of arrival and call amplitude difference with Spatial Capture Recapture to build the first ever statistical estimate of the density of calling male frogs from an acoustic array.</p>
<p>We also recorded rainfall and temperature and were surprised to find that the number of frogs calling at each site didn’t relate to either of these factors. Instead, it started off with relatively few animals calling early in the season (May), built to a fine crescendo in July and then tailed off toward October.</p>
<p>More surprising was that the area in which the microphone array could detect frog calls nearly doubled (from 400 to 800 m₂) during the winter breeding season. But because the technique accounted for this change in the size of the sampling area we could effectively monitor the calling density of the species without having to worry about the changing areas that the microphones recorded.</p>
<h2>The new direction</h2>
<p>The idea of using an array of microphones is not new. Using the time of arrival of sounds to each microphone to determine the presence of a calling animal, such as a frog, is old hat. The technique we’ve <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12810/full">pioneered</a> provides a new direction for acoustic monitoring because we were able to define the area in which the microphone array was detecting calls. </p>
<p>The study has produced a robust technique for estimating call density. This is because it combined the statistical wizardry that allowed estimates from Spatial Capture Recapture with the time of arrival and signal strength. That combination makes it possible to increase the accuracy of the estimate of call density.</p>
<p>Researchers wishing to take advantage of the wonders of digital media to monitor species at risk of climate change, <a href="https://theconversation.com/the-future-for-frogs-looks-bleak-unless-humans-change-their-habits-57505">like frogs</a>, can now use a technique that will give them call density which can be compared across recording occasions. </p>
<p>This will contribute to our understanding of how threatened species which vocalise are faring on our changing planet.</p><img src="https://counter.theconversation.com/content/69914/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Measey receives funding from National Geographic, the Centre for Invasion Biology (CIB), and the National Research Foundation (NRF). </span></em></p>A robust technique using the wonders of digital media has helped researchers understand how threatened species like frogs are faring on our globally changing planet.John Measey, Senior Researcher at the CIB based in the Department of Botany and Zoology, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/575052016-04-11T03:45:54Z2016-04-11T03:45:54ZThe future for frogs looks bleak, unless humans change their habits<figure><img src="https://images.theconversation.com/files/117973/original/image-20160408-23649-1qxbogn.jpg?ixlib=rb-1.1.0&rect=0%2C516%2C2537%2C1652&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Frogs in the Western Cape area of South Africa are susceptible to climate change.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Amphibians, the oldest group of land vertebrates, are regarded as the <a href="http://science.sciencemag.org/content/306/5702/1783">most threatened across the globe</a>. From Brazil’s tropical rain forests, to Canada’s temperate boreal forests, from fresh streams in the Alps to Australia’s temporary ponds, most populations are declining. Contributing factors include habitat destruction, invasive species, disease spread and rapid climate change. Most are human induced.</p>
<p>Frogs are ectotherms: they generate their heat from the environment around them. When the temperature changes in their native areas, frogs need to change their behaviour or habitat to stay at their preferred temperature. </p>
<p>Frogs are also generally regarded as poor dispersers among land vertebrates. This means that, unlike birds or large mammals, they find it difficult to move – or they move slowly – across landscapes. As a result, it has been suggested that they will not be able to keep track of rapid climate change because they cannot cover the distances required to match the particular climate they require. </p>
<p>South Africa’s Cape region, comprising both succulent semi-desert and <a href="http://www.fynboshub.co.za/fynbos-conservation/what-is-fynbos/">fynbos</a> vegetation, has a unique amphibian fauna that has been <a href="http://science.sciencemag.org/content/339/6115/74">recognised globally</a>. It consists of more than 50 species of frogs, 37 of which are endemic (they occur nowhere else in the world). Cape frogs are important because of their global uniqueness.</p>
<p>But their future may be under threat, and the climate of the future looks to be changing faster than the steady climate they evolved into in the past. How can we target conservation interventions to pinpoint which species or sub-populations need particular help? </p>
<h2>Confined to smaller and smaller areas</h2>
<p>Biologists have already observed that species use different methods to keep up with changes in climate. These methods broadly involve species shifting their distribution to track suitable climate, and changes in behaviour and genetic make-up to enable them to survive new climate regimes.</p>
<p>In a recently published <a href="http://www.sajs.co.za/assessing-effects-climate-change-distributions-cape-floristic-region-amphibians/mohlamatsane-m-mokhatla-dennis-r%C3%B6dder-g-john-measey">study</a>, we looked at how changes in global climate have affected the spread of the endemic Cape frog community during two key periods in recent history: the <a href="http://science.sciencemag.org/content/325/5941/710">Last Glacial Maximum</a> about 21,000 years ago; and the <a href="http://link.springer.com/article/10.1007/s00382-007-0231-3">Holocene Glacial Minimum</a> about 6,000 years ago.</p>
<p>We then projected the distributions forward into two possible future scenarios using two emission scenarios. This allowed us to ask whether the forecasted climates would significantly change the distribution of Cape frogs. By predicting these future distributions, we were able to assess whether these species are likely to move in specific directions, like north or south, or whether their distributions are likely to become fragmented. It also established which particular group of frogs is likely to be more negatively affected.</p>
<p>The results were startling. Our models suggested that the area occupied by Cape frogs today is just a fraction of the area of suitable climate space they would have had available at the Last Glacial Maximum. But comparing the current distribution with that at the Holocene Glacial Minimum provided very little evidence for change. The biggest surprise was the massive loss in suitable climate space between current distributions and future forecast scenarios in 2080. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117974/original/image-20160408-23645-gaxjo7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cape frogs are likely to be confined to a smaller space due to climate change.</span>
<span class="attribution"><span class="source">Reuters</span></span>
</figcaption>
</figure>
<p>Not only are Cape frogs likely to be confined to a much smaller area, but the rate at which they will be forced to move is faster than anything that they have experienced in a very long time. This would mean that many of the species would experience a fragmentation effect: their sub-populations would be separated beyond what they’re likely to be able to bridge through their own hopping abilities. In other words, sub-populations would become isolated from each other – and too far apart to reach each other to breed. This effectively makes each small sub-population more vulnerable to extinction.</p>
<p>Our models predict that the suitable climate space is likely to shift Cape frog distributions to the north. Based on the estimates, this has been a trend since the Last Glacial Maximum. But in the past this would have seen a movement rate equivalent to 1km per 1,000 years. The movement between the present and the worst emission scenario in 2080 is more than 500 times faster.</p>
<h2>Is there any hope?</h2>
<p>Our interest is in the trends that the data show, and asking how these potential scenarios could be mitigated by conservation actions today. For example, in the future lowland species are expected to be more fragmented than highland species. This shows the need to establish corridors of suitable habitat between existing sites for many species. </p>
<p>These areas need to be made up of both terrestrial and aquatic habitats, allowing animals to track suitable climate space as they move. Where possible, corridors should not only move between lowland sites, but link lowland to upland sites. </p>
<p>By making predictions of what may happen to the Cape community of frogs, we are providing information that may be typical for any animal with limited dispersal ability, including lizards and flightless insects. </p>
<p>The comparative datasets for many smaller invertebrates are absent. But our results could be generalised to a much larger group of ectothermic animals that are limited in their ability to move.</p>
<p>Our study has shown that despite major changes in climate, as well as available habitat in the Cape, the frogs continue to survive. Their resilience is likely to require our help in the future through conservation actions that not only preserve their current breeding and foraging sites but also enable them to move into areas with suitable climate conditions.</p>
<p>There is hope. If the global community can stick to the recent <a href="https://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf">Paris Agreement</a>, our scenario suggests that the biotic velocity – the distance and/or time to move between the point where a population is and the nearest climatically suitable space – of the Cape frog community will be roughly double that of historical rates. </p>
<p>Many conservation agencies have started <a href="http://sourcetosea.org.za/">taking specific actions</a> that would see many coastal and upland areas linked through areas of continuous reserves. </p>
<p>The study has also helped identify areas where the frogs can be monitored to assess whether climate change is likely to affect them. These include lowland areas that are already very heavily affected by humans for agriculture and living space. These areas won’t be changed back to their original state, but they could be made more tolerant of the flora and fauna that could be used as corridors. Today, frogs are reliant on the spaces that we humans make for them.</p><img src="https://counter.theconversation.com/content/57505/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Measey receives funding from the Centre of Excellence for Invasion Biology and the National Research Foundation of South Africa. </span></em></p><p class="fine-print"><em><span>Mohlamatsane is funded by the National Research Foundation (NRF) PhD Innovation bursary and the Nelson Mandela Metropolitan University (NMMU).</span></em></p>Climate change may threaten the survival of the Cape frog. The solution could lie in creating corridors for them to move to new habitats and more suitable climate spaces.John Measey, Senior Researcher at the CIB based in the Department of Botany and Zoology, Stellenbosch UniversityMohlamatsane Mokhatla, Scientist at South African National Parks & PhD student at the CIB, Department of Botany and Zoology, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/396162015-04-02T05:28:49Z2015-04-02T05:28:49ZSome shape-shifting animals that can morph to fool others<figure><img src="https://images.theconversation.com/files/76652/original/image-20150331-1256-4z6jds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pretty impressive, mimicry octopus, but you don't fool us.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/pacificklaus/6209075735/">Klaus Stiefel/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Animals come in all different shapes and sizes, but only a few can change their shapes. Researchers in Ecuador recently reported a <a href="http://onlinelibrary.wiley.com/doi/10.1111/zoj.12222/abstract">new species of frog</a> that can change its skin texture from spiny to smooth – the first ever case of a shape-shifting vertebrate.</p>
<p>When an animal is about to be attacked by a predator, it has two choices: run or hide. Sometimes, though, running might actually make the animal more obvious to its attacker. An animal that happens to look the same as its environment, however, may survive by being camouflaged from the attacker, such as <a href="http://www.mothscount.org/text/102/camouflage.html">moths that resemble fallen leaves</a>, or even help to attract prey – a tactic the <a href="https://theconversation.com/secrets-of-the-orchid-mantis-revealed-it-doesnt-mimic-an-orchid-after-all-36715">orchid mantis</a> uses.</p>
<p>Many animals have evolved such permanent adaptations that help them to mimic their environments. However, along with the newly classified mutable rain frog, there are just a few animals known to be capable of changing their shape.</p>
<h2>1. The mutable rain frog</h2>
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<a href="https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76649/original/image-20150331-1240-dncvpm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&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 mutable rain frog - blink and it may have changed form.</span>
<span class="attribution"><a class="source" href="http://www.eurekalert.org/multimedia/pub/88761.php">Zoological Journal of the Linnean Society</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This frog was discovered in the Ecuadorian rain forest in 2006 but was only recently reported in the <a href="http://onlinelibrary.wiley.com/doi/10.1111/zoj.12222/abstract">Zoological Journal of the Linnean Society</a> as it took several years to find a second specimen, and only then did the shape-shifting ability become apparent.</p>
<p>The frog visibly changes its skin in a matter of seconds, completely changing texture from spiny to smooth in a few minutes. This change is so rapid that when the first researcher captured the frog to photograph it she thought she had mistakenly taken the wrong frog specimen – the spines had disappeared. The researchers put moss in the container with the frog until they could return it to the wild, but when they checked on it later it had changed its skin texture to spiny again. </p>
<p>The team also identified a second frog species, the <a href="http://www.arkive.org/sobetes-robber-frog/pristimantis-sobetes/">Sobetes robber frog</a>, capable of the same shape-shifting behaviour. This indicates that this phenomenon could be present in many species of amphibian and is possibly just unrecorded as it happens so quickly. This is the first known vertebrate to shape-shift over such a rapid time frame – apart from werewolves and J.K Rowling’s Professor McGonagall of course.</p>
<h2>2. The golden tortoise beetle</h2>
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<a href="https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76781/original/image-20150401-31292-18ex9gf.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">It’s either this or shiny gold.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/knfk/8523800625/">Kenneth ng/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>This <a href="http://blogs.scientificamerican.com/running-ponies/2012/07/04/glad-you-ditched-the-anal-fork-golden-tortoise-beetle/">species of beetle</a> is capable of changing its colour when mating or to blend in with its background and avoid predation, just as specialist colour changers such as chameleons do. But it can also change the finish of its colour, for example from a shiny gold to a dull red colour. It does this through an optical illusion whereby tiny grooves in the shell can create a shiny surface when filled with liquid and a dull one when drained. </p>
<p>The golden tortoise beetle also undergoes a metamorphosis from the larval to the adult stage (in the same way that caterpillars morph into butterflies). This process of metamorphosis occurs through cells growing and specialising as the beetle grows to maturity and is brought about by hormonal change. </p>
<h2>3. Cuttlefish</h2>
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<img alt="" src="https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=569&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=569&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76665/original/image-20150331-1256-2w6ut8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=569&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The same cuttlefish filmed only seconds apart.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pacificklaus/14755383238/">Klaus Stiefel/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>Cuttlefish are capable of <a href="http://video.nationalgeographic.com/video/worlds-deadliest-ngs/deadliest-cuttlefish-camouflage">mimicking their background environment</a> by changing the colour, pattern and texture of their skin. They do this by altering pigments in their skin to change the way it reflects light. This is all controlled by <a href="http://news.nationalgeographic.com/news/2008/08/080608-cuttlefish-camouflage-missions_2.html">neurons in the brain</a> that transmit impulses and information to the rest of the body.</p>
<p>As well as camouflaging themselves, cuttlefish can alter their skin to startle predators or to communicate with other cuttlefish. Some cuttlefish have even been dubbed as <a href="http://www.independent.co.uk/environment/crossdressing-cuttlefish-is-casanova-of-the-reef-487413.html">cross-dressers</a>: the males have been known to imitate females in order to sneak past other males to mate with the females.</p>
<h2>4. The mimic octopus</h2>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/H8oQBYw6xxc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>This octopus was discovered in 1998 off the coast of an Indonesian island, and is perhaps the greatest shape-shifter of all. Similar to the cuttlefish, it is capable of mimicking its background environment by changing the colour and texture of its skin. However, impressively, it is the only animal able to mimic a diverse range of species – at least <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8312.2007.00948.x/abstract;jsessionid=27BD603795BCD5DB9D5E4275FC47035D.f02t03">13 have been recorded so far</a> – including lion fish, sea snakes, jellyfish and sea anemones.</p>
<p>Most of the impersonated species are poisonous, giving the mimic octopus protection from predators, but it is also known to imitate members of the opposite sex in crabs, luring them in before feasting on them. The mimic octopus has remarkable dexterity, being capable of changing its colour, behaviour, shape and texture, and can alter its mimickry according to the circumstances.</p>
<h2>5. Pufferfish</h2>
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<img alt="" src="https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/76664/original/image-20150331-1253-19ijfkt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&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">Watch out, he’s about to puff!</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/brj_bringin_the_shit_up_in_here_bitches/4933573950/in/photolist-8vXRDQ-paEnSt-5JxLA7-mNvcKT-bq1WMY-ospaFD-pSe2eJ-eaqhiQ-4EfhTH-f9dGCp-G3sjy-8xcCu2-9Rbq-akVosY-7TFe7N-do6aGC-g4Bxij-bCVUya-69E7Bn-6RUUhQ-48m5Vd-6ht4gF-KCveG-7kiNyN-oxrLB7-7keWpr-7keXx6-7kiNtq-7keZkz-7mKgV7-2jCgg6-EH6Jc-pFWuQa-87jJcQ-4XYxjt-q9dZd-7Y5JQt-3wfMh-PvbRH-4etzUv-dLeop8-s15F-rEitn-7QFLQE-4j6PdR-7xjr7k-djPHuF-8gMth-4ekaJv-agGchV">Benjamin Jakabek/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p><a href="http://www.britannica.com/EBchecked/topic/470572/porcupine-fish">Porcupinefish</a> and <a href="http://animals.nationalgeographic.com/animals/fish/pufferfish/">pufferfish</a> are a group of fish that puff themselves up rapidly when threatened. These fish can more than double their size by inflating their stomachs with water or air, making themselves much less attractive as a meal to predators – would you want to eat a large spiky ball? – and too large to be eaten by predators with smaller mouths. </p>
<p>Most porcupinefish and pufferfish also contain a deadly toxin, far more poisonous than cyanide, so if they are taken unaware the predators often won’t last for long. The meat from these fish are considered a <a href="http://edition.cnn.com/2014/04/03/travel/pufferfish-fugu-capital-shimonoseki-japan/">delicacy in Japan</a>, where it is carefully prepared by trained chefs, although it seems several customers <a href="http://animals.nationalgeographic.com/animals/fish/pufferfish/">still die</a> each year.</p><img src="https://counter.theconversation.com/content/39616/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Gentle works for Nottingham Trent University.</span></em></p>Last week, a new frog capable of shape-shifting, was discovered. Though many other animals use camouflage, there are only a few other species known which can actually shift their shape.Louise Gentle, Senior Lecturer in Animal Behaviour, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.