tag:theconversation.com,2011:/fr/topics/squid-3428/articlesSquid – The Conversation2023-03-10T23:08:16Ztag:theconversation.com,2011:article/2009432023-03-10T23:08:16Z2023-03-10T23:08:16ZSquid fishing grew by 68% in just three years, raising fears the industry is out of control<p>Global squid fishing increased by 68% between 2017 and 2020, according to our international analysis, prompting concerns that much of the international fishing fleet is sidestepping necessary conservation and management. </p>
<p>Our study, carried out with colleagues in Australia, Japan, the United States, Chile and Canada, and <a href="http://www.science.org/doi/10.1126/sciadv.add8125">published today in Science Advances</a>, reveals that almost all of the increase in squid fishing has occurred in unregulated areas, with 86% of squid fishing now occurring in places with little or no scrutiny of catch sizes. </p>
<p>Unregulated fishing poses a significant challenge to fishery sustainability and raises substantial equity concerns. While attention has tended to focus on illegal fishing, the growth in legal but unregulated fishing may pose an even bigger threat, particularly to species such as squid, whose fisheries can cover entire oceans. </p>
<p>To estimate the scale of global squid fishing, we analysed satellite imagery and vessel tracking data to see how many vessels are fishing for squid, and where and how often they operate.</p>
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Read more:
<a href="https://theconversation.com/we-now-have-a-treaty-governing-the-high-seas-can-it-protect-the-wild-west-of-the-oceans-201184">We now have a treaty governing the high seas. Can it protect the Wild West of the oceans?</a>
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<p>Squid fishing vessels are typically outfitted with powerful lamps to attract squid to the surface. These lamps are so powerful that they are visible from space. This means we can use satellite data to spot these lights at night, along with data from the ships’ <a href="https://globalfishingwatch.org/our-technology/">Automatic Identification System (AIS)</a>, which allows authorities to monitor the location and course of registered vessels.</p>
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<a href="https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&rect=5%2C0%2C987%2C659&q=45&auto=format&w=1000&fit=clip"><img alt="Fishing vessel with lamps to attract squid" src="https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&rect=5%2C0%2C987%2C659&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514628/original/file-20230310-26-3pt6kz.png?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>
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<span class="caption">Many fishing vessels use powerful lamps to attract squid to the surface.</span>
<span class="attribution"><span class="source">Simon Ager</span>, <span class="license">Author provided</span></span>
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<p>Using this data, we estimate that the amount of light-luring vessel effort increased from an estimated 149,000 vessel days in 2017, to 251,000 vessel days in 2020. Of these, 61-63% were by vessels not broadcasting their AIS, and thus only visible by the loom from their lamps. This light-luring vessel effort represents an estimated total of 801,000 vessel days over the period 2017–20.</p>
<p>Finally, we correlated these data with national and regional management bodies, and determine how much of this activity is unregulated.</p>
<h2>A complex problem</h2>
<p>Regulation and management of globalised squid fisheries is complex, because this fishing takes place both in waters that are under national jurisdiction and on the high seas. Consequently, cooperation is fundamental to ensure fisheries are regulated at sustainable levels and avoid gaps or loopholes. </p>
<p>Regional fisheries management organisations have been established through international treaties to provide the framework for such cooperation, and to regulate so-called “transboundary” fisheries. However, out of 17 such organisations in existence, only two – the <a href="https://www.npfc.int/">North Pacific Fisheries Commission</a> and the <a href="https://www.sprfmo.int/">South Pacific Fisheries Management Organisation</a> – have dealt with squid fisheries. This means there are still large gaps in the Indian and Atlantic oceans. </p>
<p>Furthermore, it is not enough to create a regional fisheries management organisations; parties must also ensure the organisation actually adopts regulations. The United Nations’ <a href="https://www.fao.org/documents/card/es/c/71be21c9-8406-5f66-ac68-1e74604464e7/">International Plan of Action to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing</a> defines unregulated fishing (among other things) as that which occurs “in areas or for fish stocks in relation to which there are no applicable conservation or management measures”. Regional fisheries management organisations must do more than simply exist or adopt general measures if their fisheries are to be considered regulated. </p>
<h2>What we found</h2>
<p>Our analysis defines “regulated” fisheries as those within the exclusive economic zones of coastal countries, or within regional fisheries management organisations that have implemented specific conservation and management measures for squid stocks. In contrast, we define “unregulated” fisheries as those on the high seas where there is no such organisation in place, or where the relevant organisation has failed to adopt regulations pertaining specifically to squid stocks. </p>
<p>Using satellite imagery, vessel tracking, and data monitoring, our study found that globalised light-luring squid fishing fleets are truly global in scope, fishing across multiple oceans within a given year, moving freely between regulated and unregulated spaces, and catching vast amounts of squid with little or no oversight. Often, there is no requirement to report their catches to anyone other than their flag nation, with little or no independent verification.</p>
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<img alt="" src="https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513837/original/file-20230306-18-30mr6u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&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">Globalized squid fishing vessel connectivity. The number and size of circles corresponds to the vessels that fished in each ocean region (NW Pacific Ocean- purple; SE Pacific Ocean- teal; SW Atlantic Ocean- green; NW Indian Ocean- pink). The width of white connecting lines and numbers correspond to the vessels that were observed in both regions connected.</span>
<span class="attribution"><span class="source">Citation forthcoming</span></span>
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<p>Unregulated spaces are often directly adjacent to regulated ones, and different fleets often target the same fisheries. This creates equity concerns for coastal communities that rely on species targeted by large industrial fleets, and for the governments of developing nations that depend on revenue from stocks that move between regulated and unregulated areas. </p>
<p>Furthermore, many of the fishing vessels carrying out unregulated fishing stay at sea for exceptionally long periods (months to years), often refuelling and offloading their catches to other vessels while still at sea, and thus avoiding the oversight that accompanies port calls. </p>
<p>Like all activities that draw on global resources, fishing on transboundary stocks should be fully regulated. Yet the regional bodies with the competence to adopt management measures are often restrained by distant water fishing nations that stall or oppose conservation and management measures. </p>
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Read more:
<a href="https://theconversation.com/chinese-fishing-boats-took-half-a-billion-dollars-of-illegal-squid-from-north-korea-scientists-used-satellites-to-catch-them-out-142642">Chinese fishing boats took half a billion dollars of illegal squid from North Korea. Scientists used satellites to catch them out</a>
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<p>The global squid fishery shows how important it is to strengthen regional management of high seas resources and to continue international calls for states and regional bodies to take this challenge seriously. These fisheries are ultimately shared by us all, yet few receive any benefit, and nearby countries’ own fish stocks are sometimes unfairly depleted. </p>
<p>Furthermore, the trans-oceanic nature of these fisheries highlights the crucial importance of comprehensive data-sharing agreements between regional fisheries management organisations for improving understanding of the movements of these vessels, and quantifying their impacts on squid stocks.</p><img src="https://counter.theconversation.com/content/200943/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Quentin Hanich's participation in this study was funded by Global Fishing Watch and Oceans 5.</span></em></p><p class="fine-print"><em><span>Katherine Seto is a Global Fishing Watch research partner and an Honorary Fellow of the Australia National Centre for Ocean Resources and Security (ANCORS). </span></em></p><p class="fine-print"><em><span>Adviser for the Chilean Government prior to 2022. Consultant for international and inter-governmental organisations.</span></em></p>Almost all the growth in global squid fishing has happened in unregulated waters, meaning fishing crews aren’t subject to conservation or marine management programs.Quentin Hanich, Professor, University of WollongongKatherine Seto, Research Fellow, University of WollongongOsvaldo Urrutia, Associate professor, Pontificia Universidad Catolica de ValparaisoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1850772022-06-23T15:02:57Z2022-06-23T15:02:57ZEvolutionary tree of life: modern science is showing how we got so much wrong<figure><img src="https://images.theconversation.com/files/469018/original/file-20220615-16-esfdjk.jpg?ixlib=rb-1.1.0&rect=41%2C0%2C3026%2C2037&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lunkwill42/3658339290">Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If you look different to your close relatives, you may have felt separate from your family. As a child, during particularly stormy fall outs you might have even hoped it was a sign that you were adopted. </p>
<p>As our new research shows, appearances can be deceptive when it comes to family. New DNA technology is shaking up the family trees of many plants and animals. </p>
<p>The primates, to which humans belong, were once thought to be close relatives of bats because of some similarities in our <a href="https://www.sciencedirect.com/science/article/abs/pii/0047248487900583">skeletons</a> and <a href="https://en.wikipedia.org/wiki/Flying_primate_hypothesis">brains</a>. However, DNA data now places us in a group that includes rodents (rats and mice) and rabbits. Astonishingly, bats turn out to be more closely related to cows, <a href="https://www.newscientist.com/article/dn9402-bats-and-horses-get-strangely-chummy/">horses</a> and even rhinoceroses than they are to us. </p>
<p>Scientists in Darwin’s time and through most of the 20th century could only work out the branches of the evolutionary tree of life by looking at the structure and appearance of animals and plants. Life forms were grouped according to <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cladistics">similarities thought to have evolved together</a>.</p>
<p>About three decades ago, scientists started using DNA data to build “molecular trees”. Many of the first trees based on DNA data were at odds with the classical ones. Sloths and anteaters, armadillos, pangolins (scaly anteaters) and aardvarks were once thought to belong together in a group called edentates (“no teeth”), since they share aspects of their anatomy. Molecular trees showed that these traits evolved independently in different branches of the mammal tree. It turns out that aardvarks are more closely related to elephants while pangolins are more closely related to cats and dogs. </p>
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<span class="caption">Molecular phylogenies show that mammals as different in appearance as aardvarks, manatees, elephant shrews and elephants are really close cousins.</span>
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<h2>Coming together</h2>
<p>There is another important line of evidence that was familiar to Darwin and his contemporaries. <a href="https://www.youtube.com/watch?v=s5P4uYsK8_c#t=2m38s">Darwin noted</a> that animals and plants that appeared to share the closest common ancestry were often found close together geographically. The location of species is another strong indicator they are related: species that live near each other are more likely to share a family tree.</p>
<p>For the first time, our <a href="https://www.nature.com/articles/s42003-022-03482-x">recent paper</a> cross-referenced location, DNA data and appearance for a range of animals and plants. We looked at evolutionary trees based on appearance or on molecules for 48 groups of animals and plants, including bats, dogs, monkeys, lizards and pine trees. Evolutionary trees based on DNA data were two-thirds more likely to match with the location of the species compared with traditional evolution maps. In other words, previous trees showed several species were related based on appearance. Our research showed they were far less likely to live near each other compared to species linked by DNA data.</p>
<p>It may appear that evolution <a href="https://en.wikipedia.org/wiki/Endless_Forms_Most_Beautiful">endlessly invents new solutions</a>, almost without limits. But it has fewer tricks up its sleeve than you might think. Animals can look amazingly alike because they have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633856/">evolved to do a similar job</a> or live in a similar way. Birds, bats and the extinct pterosaurs have, or had, <a href="https://theconversation.com/curious-kids-how-did-some-animals-evolve-wings-to-fly-148496">bony wings for flying</a>, but their ancestors all had front legs for walking on the ground instead. </p>
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<span class="caption">The colour wheels and key indicate where members of each order are found geographically. The molecular tree has these colours grouped together better than the morphological tree, indicating closer agreement of the molecules to biogeography. Figure is from Oyston et al. (2022)</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<p>Similar wing shapes and muscles evolved in different groups because the physics of generating thrust and lift in air are always the same. It is <a href="https://www.youtube.com/watch?v=u6Ol_a9oV_M&t=73s">much the same with eyes</a>, which <a href="https://rdcu.be/cO0Xo">may have evolved 40 times in animals</a>, and with only a few basic “designs”. </p>
<p>Our eyes are similar to squid’s eyes, with a crystalline lens, iris, retina and visual pigments. Squid are more closely related to snails, slugs and clams than us. But many of their mollusc relatives have only the simplest of eyes.</p>
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<span class="caption">Squid and fish are actually separated by more than half a billion years of evolution.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pacificklaus/8751081489">Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Moles evolved as blind, burrowing creatures at least four times, on different continents, on different branches of the mammal tree. The Australian marsupial pouched moles (more closely related to kangaroos), African golden moles (more closely related to aardvarks), African mole rats (rodents) and the Eurasian and North American talpid moles (beloved of gardeners, and more closely related to hedgehogs than these other “moles”) all evolved down a similar path. </p>
<h2>Evolution’s roots</h2>
<p>Until the advent of cheap and efficient gene sequencing technology in the 21st century, appearance was usually all evolutionary biologists had to go on.</p>
<p>While Darwin (1859) showed that all life on Earth is related in a single evolutionary tree, he did little to map out its branches. The anatomist Ernst Haeckel (1834-1919) was one of the first people to draw evolutionary trees that tried to show how major groups of life forms are related. </p>
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<span class="caption">The german zoologist Ernst Haeckel’s illustrations (here, groups of mosses)</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/moose-eurhynchium-haeckel-muscinae-63103/%20%20and%20https://en.wikipedia.org/wiki/Ernst_Haeckel#/media/File:Tree_of_life_by_Haeckel.jpg">Pixaby</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>Haeckel’s drawings made brilliant observations of living things that influenced art and design in the 19th and 20th centuries. His family trees were based almost entirely on how those organisms looked and developed as embryos. Many of his ideas about evolutionary relationships were held until recently. As it becomes easier and cheaper to obtain and analyse large volumes of molecular data, there will be many more surprises in store.</p><img src="https://counter.theconversation.com/content/185077/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Wills receives funding from NERC and JTF grant 61408</span></em></p>DNA analysis is beginning to reveal how wrong the long-accepted evolutionary tree is.Matthew Wills, Professor of Evolutionary Palaeobiology at the Milner Centre for Evolution, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1683582022-05-09T12:05:02Z2022-05-09T12:05:02ZWhat does an octopus eat? For a creature with a brain in each arm, whatever’s within reach<figure><img src="https://images.theconversation.com/files/443875/original/file-20220201-25-lb03xa.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4747%2C3172&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Don't call them tentacles: An octopus has eight arms.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/common-octopus-royalty-free-image/495907882?adppopup=true">TheSP4N1SH/iStock via Getty Images Plus</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>
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<blockquote>
<p><strong>What does an octopus eat? – Lily, age 4, Maryland</strong></p>
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<hr>
<p>The octopus is one of the coolest animals in the sea. </p>
<p>For starters, they are <a href="https://www.nationalgeographic.com/animals/invertebrates">invertebrates</a>. That means they don’t have backbones like humans, lions, turtles and birds. </p>
<p>That may sound unusual, but actually, nearly all animals on Earth are invertebrates – about 97%. </p>
<p><a href="https://www.grammarly.com/blog/octopi-octopuses/">Octopuses</a> are a specific type of invertebrate called <a href="https://www.youtube.com/watch?v=myW5YSAAypg">cephalopods</a>. The name means “head-feet” because the arms of cephalopods surround their heads. Other types of cephalopods include squid, nautiloids and cuttlefish. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/sAYkjkHNCAU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An exciting nature documentary about squids and octopuses.</span></figcaption>
</figure>
<h2>What do they eat?</h2>
<p><a href="https://erintspencer.com/">As marine ecologists</a>, <a href="https://case.fiu.edu/about/directory/profiles/papastamatiou-yannis.html">we conduct research</a> on how ocean animals interact with each other and their environments. We’ve mostly studied fish, from <a href="https://oceanservice.noaa.gov/facts/lionfish-facts.html">lionfish</a> to <a href="https://www.montereybayaquarium.org/animals/animals-a-to-z/sharks">sharks</a>, but we have to confess we remain captivated by octopuses. </p>
<p>What octopuses eat depends on what species they are and where they live. Their prey includes gastropods, like snails and sea slugs; bivalves, like clams and mussels; crustaceans, like lobsters and crabs; and fish. </p>
<p>To catch their food, octopuses use <a href="https://www.youtube.com/watch?v=abRPaXgJGQg">lots of strategies and tricks</a>. Some octopuses wrap their arms – not tentacles – around prey to pull them close. Some use their hard beak to drill into the shells of clams. All octopuses are venomous; they inject toxins into their prey to overpower and kill them.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/I0qykuyIqNk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Watch an octopus catch prey – and spray ink.</span></figcaption>
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<h2>Where do they live?</h2>
<p>There are about 300 species of octopus, and they’re found in <a href="https://kids.nationalgeographic.com/animals/invertebrates/facts/octopus">every ocean in the world</a>, even in the frigid waters around Antarctica. A <a href="https://www.livescience.com/50322-antarctic-octopus-blue-blood.html">special substance in their blood</a> helps those cold-water species get oxygen. It also turns their blood blue. </p>
<p>You can find octopuses at different depths too. Some are found on warm tropical reefs just a few feet below the surface of the water. Others live deep in the sea, practically in the dark. The species that goes deepest is the <a href="https://www.bbc.com/news/science-environment-52839678">dumbo octopus</a>, spotted at 22,800 feet down – that’s more than 4 miles (almost 7 kilometers).</p>
<h2>How smart are they?</h2>
<p>Octopuses are at the head of the class. They are among the <a href="https://www.nhm.ac.uk/discover/octopuses-keep-surprising-us-here-are-eight-examples-how.html">smartest invertebrates on Earth</a>. They have <a href="https://biogeoplanet.com/why-do-octopuses-have-9-brains-8-arms-3-hearts-and-blue-blood-surprising-facts/#:%7E:text=Octopuses%20have%209%20brains%20because,hemocyanin%2C%20a%20copper%20rich%20protein.">nine brains</a> – one mini-brain in each arm and another in the center of their bodies. Each arm can independently taste, touch and perform basic movements, but all arms can also work together when prompted by the central brain. </p>
<p>Octopuses put their brains to good use. They can solve mazes and puzzles, particularly when food is the reward. Sometimes they even outsmart people: At the <a href="https://www.nationalaquarium.co.nz/">New Zealand National Aquarium</a>, Inky figured out how to <a href="https://www.nationalgeographic.com/animals/article/160414-inky-octopus-escapes-intelligence">sneak out of his tank</a> and escape to the ocean through a drainpipe. </p>
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<figcaption><span class="caption">Watch an octopus earn its meal by solving a puzzle.</span></figcaption>
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<h2>How do they change color?</h2>
<p>Octopuses are experts at disguising themselves so they can blend in with their surroundings. One way they do it is <a href="https://www.youtube.com/watch?v=XocHDvHlcJM">by changing color</a>. Special cells, <a href="https://oceanconservancy.org/blog/2019/10/07/octopuses-change-color/">called chromatophores</a>, receive a signal from the brain to tighten the muscles to show more color, or loosen them to show less. Blue, green, pink, gray – <a href="https://www.youtube.com/watch?v=yE0QqxwyL_8">they turn those colors and more</a> to hide from predators, attract mates, draw in prey and warn enemies to stay away. </p>
<p>Some species also <a href="https://ocean.si.edu/ocean-life/invertebrates/how-octopuses-and-squids-change-color">change their skin texture</a>, making it smoother or bumpier, so they can <a href="https://www.youtube.com/watch?v=q8xJ13pAZNw">camouflage themselves in rocks and foliage</a>. Some spray ink when confronted by predators like sharks; this allows the octopus enough time to swim to safety. </p>
<p>The mimic octopus is particularly clever. It moves its arms in particular ways to <a href="https://www.nature.com/scitable/blog/accumulating-glitches/the_mimic_octopus_master_of/">imitate other ocean animals</a>. For example, if it wants to look fierce, it extends two black-and-white striped arms out wide to look like the venomous sea snake. Or it flattens itself along the sea floor, arms next to its body, to look like a poisonous flatfish. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Wos8kouz810?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The mimic octopus can imitate the look of other sea creatures.</span></figcaption>
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<h2>The octopus at risk</h2>
<p>When confronting humans, an octopus tends to be nonaggressive – just as long as you give them space, like you would any ocean animal.</p>
<p>Although octopuses have ways to avoid predators, they remain at risk <a href="https://climatekids.nasa.gov/ocean/#:%7E:text=As%20Earth%20warms%2C%20NASA%20has,to%20melting%20ice%20on%20land.">from other threats</a>: chemical pollutants, marine debris, habitat loss, overfishing and climate change. </p>
<p>But all of us humans can help by making ocean-smart choices. That includes learning how to <a href="https://climatekids.nasa.gov/how-to-help/">cut back on carbon emissions</a> and <a href="https://www.natgeokids.com/uk/kids-club/cool-kids/general-kids-club/tips-to-reduce-plastic-pollution/">using less plastic</a>. Doing these things will help the octopus and other marine creatures not only survive, but thrive. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/vjOmyNA4wZ8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Here are ways you can help keep our oceans clean.</span></figcaption>
</figure>
<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>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/168358/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>With nine brains, blue blood and a talent for camouflage, the octopus is one of the most fascinating creatures in the sea.Erin Spencer, Ph.D. Student in Biology, Florida International UniversityYannis Papastamatiou, Professor of Biological Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1785662022-03-08T16:00:06Z2022-03-08T16:00:06ZMeet the ten-armed, 325-million-year-old octopus fossil named after President Joe Biden<figure><img src="https://images.theconversation.com/files/450476/original/file-20220307-27-rnkcwc.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C1800%2C1350&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">K Whalen</span></span></figcaption></figure><p>In an ancient shallow bay of what is now Montana, the body of an octopus-like creature the size of a fist was buried on the seafloor. Some 325-328 million years later, a new paper published in <a href="https://www.nature.com/articles/s41467-022-28333-5">Nature Communications</a> provides some interesting insights into this mysterious and ancient cephalopod. </p>
<p><em>Syllipsimopodi bideni</em> is small (about 12cm in length), has ten arms, suckers, fins, and a triangular pen of hard tissue inside its body for support. It’s a unique find because “squishy” animals tend to degrade quickly after death and therefore rarely make good fossils. </p>
<p>We don’t know when this unusual fossil was discovered, but in 1988 it was donated to the Royal Ontario Museum in Canada. It would sit largely ignored for more than 30 years until American palaeontologists Christopher Whalen and Neil Landman decided to study it.</p>
<p>The researchers have named the species <em>Syllipsimopodi bideni</em> after Joe Biden, the 46th president of the United States. Biden had just been inaugurated when the study was submitted for publication, and the authors wanted to recognise his commitment to science. </p>
<p>Cephalopods are some of the most diverse and fascinating molluscs on our planet. They have conquered every ocean, survived the five biggest extinctions in Earth’s history, and today number around <a href="http://www.thecephalopodpage.org/">800 species</a>.</p>
<p>Octopuses and squids are among the most familiar cephalopods, but also in this group are cuttlefishes, nautilus and the extinct belemnites, ammonites and others. Their economic and cultural importance is immense, and their ecological roles are vital for healthy oceans.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/clever-cuttlefish-show-advanced-self-control-like-chimps-and-crows-155795">Clever cuttlefish show advanced self-control, like chimps and crows</a>
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<h2>An exceptional fossil</h2>
<p>Ammonites and their relatives are important tools for geologists, who use the unique patterns on their tough coiled shells to identify layers of rock around the world. But the fossil record for cephalopods without shells is a stark contrast, because when these animals die the flesh of their bodies usually rots away, leaving very little, if anything, behind. Sadly, we will probably never know about the vast majority of species that existed, let alone what their relationships were to one another.</p>
<p>Some help has come from <a href="https://academic.oup.com/mollus/article/73/4/399/1028980?login=true">genetic studies</a> that have defined two major living groups: the squid relatives and the octopus relatives. But genetic material cannot be extracted from fossils that may be hundreds of millions of years old, so the full story of their evolution has remained unresolved.</p>
<p>Under special chemical and environmental conditions, the soft parts of an animal can be preserved in the rock. The Bear Gulch Limestone fossil site (where this new species was found) is famous for this kind of preservation and provides incredibly rare insights about these animals. This allowed Whalen and Landman to describe important parts of the new species’ anatomy, which give clues about its identity.</p>
<figure class="align-center ">
<img alt="An octopus." src="https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450495/original/file-20220307-85970-17eqbjc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It’s difficult to study fossils of cephalopods without a hard shell, like octopuses.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-view-common-octopus-vulgaris-1340447465">Henner Damke/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Vampires from hell</h2>
<p>The authors suggest that <em>Syllipsimopodi bideni’s</em> features make it the oldest member of a group called the <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1111/pala.12267">vampyropods</a>. This is the group of cephalopods that includes modern octopuses and the “vampire squid”. </p>
<p>While octopuses will be familiar to you, the vampire squid may not. There is a single surviving species, <a href="https://www.sciencedirect.com/science/article/pii/S0967063720301527"><em>Vampyroteuthis infernalis</em></a>, whose name means “vampire squid from hell”, despite being more closely related to octopuses. </p>
<p><em>Vampyroteuthis infernalis</em> lives a quiet life, drifting in deep oceans around the world in waters almost devoid of oxygen and in pitch darkness. It is perhaps unworthy of its fearsome name.</p>
<p>Notably, the vampire “squid” has primitive features in common with this new species <em>Syllipsimopodi bideni,</em> such as ten limbs and a stiff internal shell. No living octopus has either of these. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/octopuses-can-defy-their-genetic-instructions-and-its-slowed-down-their-evolution-75663">Octopuses can defy their genetic instructions – and it's slowed down their evolution</a>
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<p>Until now, it was thought that the vampyropods (octopus relatives) originated in the Triassic period around 240 million years ago. But this new species pushes that back a further 82 million years, which is more time than separates humans from <em>Tyrannosaurus rex</em>.</p>
<h2>A day in the life</h2>
<p>Beyond what this fossil can tell us about cephalopod evolution, the authors also investigated the animal’s ecology. Shaped like a torpedo, the creature probably used jet-propulsion to move through the water (like many living cephalopods), and the rounded fins on either side of its body for stability. </p>
<p>One pair of arms is longer than the others, suggesting they were used to catch prey, while the suckers may have helped it manipulate its food. It is fascinating that while <em>Syllipsimopodi bideni</em> was more closely related to the octopuses, it probably lived in a similar way to true squid today. </p>
<p>While the full picture of cephalopod evolution is still murky, this fossil is a fascinating and exciting new piece of the puzzle.</p><img src="https://counter.theconversation.com/content/178566/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Fletcher 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 fossil is the oldest known vampyropod to date.Tom Fletcher, Honorary Research Fellow in Palaeobiology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1568242021-03-17T18:01:44Z2021-03-17T18:01:44ZRisk versus reward on the high seas – skinny elephant seals trade safety for sustenance<figure><img src="https://images.theconversation.com/files/389965/original/file-20210316-15-139gw3g.jpg?ixlib=rb-1.1.0&rect=370%2C531%2C7872%2C4956&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Female elephant seals take seven-month feeding trips during which they balance danger, starvation and exhaustion.</span> <span class="attribution"><a class="source" href="https://costa.eeb.ucsc.edu/">Dan Costa</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Every year, northern elephant seals set off on a <a href="https://doi.org/10.1371/journal.pone.0036728">seven-month, 6,000-mile (10,000-kilometer) journey</a> across the North Pacific ocean in search of fish and squid to eat. They start the journey after sitting on the beach for a couple months – <a href="https://doi.org/10.1073/pnas.1506520112">replacing their fur</a> and losing fat – and gradually gain weight over the course of the foraging trip. On these excursions, elephant seals don’t just swim on the surface – they <a href="https://doi.org/10.1139/z88-064">dive continuously</a>, day and night.</p>
<p>To rest, they <a href="https://doi.org/10.1139/z97-004">swim down hundreds of meters below the ocean surface</a> then slowly roll onto their backs and drift back and forth like <a href="https://doi.org/10.1098/rsbl.2009.0719">falling leaves</a>. These dives last around 25 minutes and are called drift dives. The resting period of drift dives is the most dangerous time for an elephant seal: Waking up in the jaws of a <a href="https://doi.org/10.1038/s41598-019-39356-2">white shark or killer whale</a> is not a good way to start the day.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A seal floating asleep." src="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Elephant seals rest underwater where they float upward or sink slowly down depending on whether they are fat or skinny.</span>
<span class="attribution"><span class="source">Danielle Dube through an Art-Science Residency with the UC Santa Cruz Norris Center for Natural History</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We are two biologists studying <a href="https://scholar.google.com/citations?user=ET7UYVoAAAAJ&hl=en&oi=ao">diving behavior</a> and <a href="https://scholar.google.com/citations?user=mSTFM0EAAAAJ&hl=en&oi=ao">sleep</a> in <a href="https://www.jessiekb.com/">marine mammals</a>. Specifically, we are fascinated by the decisions that elephant seals make as they roam the open ocean and navigate extreme changes in their <a href="https://doi.org/10.1111/ele.12871">environment</a> and <a href="https://doi.org/10.1098/rsbl.2017.0722">their own bodies</a>. The open ocean is a dangerous place, and animals have to continuously weigh the risks of predation, starvation and exhaustion. Choosing when to rest and when to feed has serious consequences. </p>
<p>Elephant seals have two options: rest during the safety of the dark night and feed during the day when food is harder to come by, or rest during the day when there is a much higher chance of <a href="https://doi.org/10.1038/s41598-019-39356-2">being eaten by a predator</a> and feed during the night when fish and squid are more available.</p>
<p>So we wondered, do skinny, hungry seals take more risks than plump, healthy seals? Our newest study, just published in the journal <a href="https://advances.sciencemag.org/content/7/12/eabd9818">Science Advances</a>, reveals that elephant seals fine-tuned their risk–taking behavior throughout the foraging trip.</p>
<iframe src="https://www.google.com/maps/d/u/0/embed?mid=1EOJAEebLBVvCynmmwTPDRTi5qVY_fyUa" width="100%" height="480" caption="Map of elephant seal foraging routes."></iframe>
<figure><figcaption><span class="caption">This interactive map shows foraging routes for individual seals used in the study. Zoom in and click on a route to learn more about that seal’s journey and habits.</span></figcaption></figure>
<h2>Risk vs. reward</h2>
<p>One simple question is fundamental to ecologists’ understanding of the natural world: Do hungry animals take more risks to find food? This should be <a href="http://dx.doi.org/10.1098/rspb.2018.0180">true in theory</a>, because wild animals perpetually weigh the <a href="https://doi.org/10.1098/rstb.2010.0207">risks of starvation and predation</a>. For most species, it is nearly impossible to <a href="https://doi.org/10.1038/s41598-019-46487-z">measure continuous changes in health</a>. As a result, many theories about risk and reward in the animal kingdom have been around for decades but have yet to be tested. </p>
<p>The ocean is a fascinating place to study risk and reward, because light levels determine life and death in three dimensions: The surface of the ocean is bright, and predators can hunt much more easily; but the <a href="https://oceanservice.noaa.gov/facts/light_travel.html#:%7E:text=Sunlight%20entering%20the%20water%20may,on%20depth%20and%20light%20level">light quickly fades</a> as you dive deeper into the ocean. For elephant seals, light levels are directly related to risk, because their main predators <a href="https://doi.org/10.1023/A:1007520931105">inhabit shallow waters</a> and <a href="https://www.jstor.org/stable/29775147?casa_token=c3uShnPqeLsAAAAA%3ArGI-v02t04zdz0mbAYJC5sPIa0EwivRk4eUt4qiV1HJc29nZHRInPnpKKEvzZG_WYxAj54hU3QeLrJmm0l9AYIYqRYIHajzETL1RjRkruyQn74BUfMRu&seq=1#metadata_info_tab_contents">use light to hunt</a>. For elephant seals, resting is safer at night when predators can’t find them. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seals over a gradient of light levels during day and night" src="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sleeping seals face the highest risk during the daytime and in shallow water, whereas risk is lowest during the nighttime and in deep water.</span>
<span class="attribution"><span class="source">Illustrations by Danielle Dube, Infographic by Jessica Kendall-Bar</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Light levels are also directly related to reward, because most elephant seal prey – <a href="https://doi.org/10.3389/fmars.2018.00430">fish and squid</a> – migrates <a href="https://www.cell.com/current-biology/pdf/S0960-9822(14)01067-7.pdf">up and down in the water column each day</a>. During the day, when light levels are high, fish and squid remain in the depths to avoid predators. However, at night, when light levels are low, fish and squid swim up closer to the surface to feed on phytoplankton. For seals, foraging is <a href="https://doi.org/10.2307/4616">more efficient at night</a>, when prey have emerged from the depths to find their own food. </p>
<p>This means the best time to eat is also the safest time to rest, and seals must pick one behavior over the other. Do they prioritize resting safely or feeding efficiently? And does this change over time as they gain fat?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A female elephant seal swimming in the ocean with small tags on her head and back." src="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A female elephant seal carries a satellite tag (on her head) and time-depth recorder (on her back).</span>
<span class="attribution"><span class="source">Dan Costa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Drift dives provide the answers</h2>
<p>Thanks to a long-term monitoring program led by our colleague <a href="https://www.youtube.com/watch?v=4IbSp9Ha_zs">Dan Costa</a>, our team had access to dive data from 71 adult female elephant seals <a href="https://www.youtube.com/watch?v=rMvfJGo0Coo">tagged with small devices</a> that record time, depth, light, latitude and longitude every four seconds.</p>
<p>Interestingly – and central to this research – when seals perform drift dives, <a href="https://doi.org/10.1111/j.1365-2656.2010.01735.x">fat seals float upward while skinny seals sink down</a>. This means we can use drifting rates from our dive data to <a href="https://doi.org/10.1093/beheco/ary183">calculate the seals’ percentage of body fat</a> through time. Using data on light, depth and time, we can also approximate risk level. In other words, we know if seals are fat or skinny, and we know how much risk they are taking. Even better, we know both of these metrics continuously over the entire course of their foraging trips.</p>
<p>By simultaneously measuring body fat and risk-taking through time, we learned that elephant seals <a href="https://advances.sciencemag.org/content/7/12/eabd9818">took more risks when they were skinnier and prioritized safety when they were fatter</a>. Early in the foraging trip, when seals on average had a slim 22% body fat, they rested just after sunrise – 80% of their rest dives occurred during the high-risk daytime. This allowed them to do most of their foraging at night, when food is easier to find. </p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>.]</p>
<p>Later in the foraging trip, when seals had plumped up to 35% body fat, they rested just before sunrise. Only 30% of their rest dives occurred during the high-risk daytime. Gradual shifts in body condition and behavior over the 220-day foraging trip accumulated to an impressive <a href="https://www.jessiekb.com/lightscapes-of-fear">six–hour shift in average rest time</a> by the end of the trip.</p>
<p>We also discovered that fatter seals rested 300 feet (100 meters) deeper in the water – where it is also 300 times darker – than where thinner seals rested. This further supports the idea that seals are strategically modifying their exposure to light levels – using both rest schedule (time) and rest depth (space) – to minimize risk. We call this the <a href="https://advances.sciencemag.org/content/7/12/eabd9818">lightscape of fear</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/x3ugpT1ej0M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Animation by Jessica Kendall-Bar, with illustrations by Danielle Dube through an Art-Science Residency with the UC Santa Cruz Norris Center for Natural History.</span></figcaption>
</figure>
<h2>Lessons from seals at sea</h2>
<p>Our study provides a window into the real-time decision-making of an elephant seal in the open ocean as it weighs consequences of a nap below the ocean surface. Although light has previously been identified as a <a href="https://doi.org/10.1126/science.aar7121">critical environmental constraint</a>, no study has continuously monitored an animal’s use of the lightscape relative to extreme shifts in its fat stores and health.</p>
<p>By tracking these metrics together, we were able to better understand the behavior of a wild animal trying to find food while trying to avoid becoming food. Using elephant seals as a model, we can begin to understand how these rules apply to other species – from birds to bats to bears – and scale up to influence entire ecosystems.</p><img src="https://counter.theconversation.com/content/156824/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roxanne Beltran receives funding from the National Science Foundation and National Geographic.</span></em></p><p class="fine-print"><em><span>Jessica Kendall-Bar receives funding from the National Science Foundation and the Office of Naval Research. </span></em></p>By measuring how and when elephant seals sleep, researchers were able to figure out how elephant seals change their risk-taking behavior as they gain weight.Roxanne Beltran, Assistant Professor of Ecology and Evolutionary Biology, University of California, Santa CruzJessica Kendall-Bar, PhD Candidate in Ecology and Evolutionary Biology, University of California, Santa CruzLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1547662021-02-16T17:38:23Z2021-02-16T17:38:23ZRobot jellyfish could help service offshore windfarms<figure><img src="https://images.theconversation.com/files/384549/original/file-20210216-17-1poxi5b.jpg?ixlib=rb-1.1.0&rect=0%2C300%2C2937%2C2604&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our robot is inspired by the common moon jellyfish.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/underwater-blue-background-pink-jellyfish-109189799">Willyam Bradberry/Shutterstock</a></span></figcaption></figure><p>Some of the last areas of pristine and untouched wilderness on Earth exist beneath the seas. Yet these marine ecosystems are under threat from deep-sea mining projects, oil rigs and offshore windfarms. When these facilities are built and maintained, they tend to damage the rich ecological networks around them.</p>
<p>Roboticists and engineers are working to address this problem, searching for new ways to create machines that might help repair, maintain or inspect the undersea components of the growing offshore industry. Led by colleagues Thierry Bujard and Gabriel Weymouth from the University of Southampton, my team has <a href="https://robotics.sciencemag.org/content/6/50/eabd2971.full">found a solution</a> to this problem, designing underwater robots inspired by nature’s smartest swimmers: the ultra-efficient moon jellyfish.</p>
<p>Traditional aquatic robots are designed for two main purposes: for efficient, <a href="https://oceanservice.noaa.gov/facts/auv-rov.html">long-distance navigation</a> across open stretches of water, and for tasks requiring high manoeuvrability close to submerged structures. Both types of robot are effective, but few robots combine efficient travel with high manoeuvrability. That means most aquatic robots are too clumsy and clunky to support the offshore industry without also harming the undersea environment. </p>
<p>Indeed, with the expansion of offshore developments to increasingly fragile environments, even state-of-the-art marine robots are struggling to cope with the complexity of their missions. Lots of research is currently going into developing autonomous deep sea robots, with initiatives like <a href="https://www.xprize.org/prizes/ocean-discovery">Xprize</a> offering funding to some of the most exciting ideas.</p>
<h2>Marine machines</h2>
<p>To respond to these challenges, engineers have looked to biology to inspire new forms of robotic underwater propulsion. After millions of years of evolution, the logic goes, aquatic creatures should offer models to help address the weaknesses of the current crop of underwater robots. </p>
<p>The swimming mode of fish, based on the flapping of their different fins, has become the primary source of inspiration for those <a href="https://www.imperial.ac.uk/news/164317/robotic-fish-designed-protect-real-ones/">experimenting with new underwater vehicles</a>. But the pulse-jet swimming mode favoured by jellyfish is widely regarded as the world’s most efficient underwater propulsion mechanism, offering a more compelling technological solution that’s far easier for roboticists to imitate.</p>
<p>Pulse-jetting relies on the cyclic expansion and contraction of a hollow cavity of the specimen’s body. This system drives the ingestion and expulsion of water, which ultimately provides jellyfish with a form of propulsion.</p>
<p>Despite its simplicity, this swimming strategy can result in incredible agility as well as being highly energy efficient. The fastest squid can travel up to <a href="https://academic.oup.com/icb/article/48/6/720/836259">8 metres per second</a> using a pulse-jet system, while the jellyfish <em>Aurelia aurita</em> (also known as the moon jellyfish) is known to be <a href="https://doi.org/10.1073/pnas.1306983110">the most efficient swimmer on the planet</a>.</p>
<p>By copying these organisms when we build underwater robots, we can design new underwater vehicles capable of combining high manoeuvrability with unmatched efficiency. In our <a href="https://robotics.sciencemag.org/content/6/50/eabd2971.full">recent research</a>, we developed a new bio-inspired robot that can match the propulsive efficiency of the <em>Aurelia aurita</em>. To do this, we mimicked the key principle that enables jellyfish to achieve their high propulsive efficiency: resonance.</p>
<figure class="align-center ">
<img alt="A purple jellyfish against a black background" src="https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384290/original/file-20210215-21-1qbzayr.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 <em>Aurelia aurita</em> or moon jellyfish is regarded as the most efficient swimmer on Earth.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-beautiful-moon-jellyfish-aurelia-aurita-146877323">Richard A McMillin/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Resonant robotics</h2>
<p>Resonance is a physical phenomenon commonly encountered in many everyday activities such as walking, playing on a swing and <a href="https://doi.org/10.1038/427116a">even singing</a>. If we watch a swinging pendulum, for example, we know from experience that it will continue oscillating until it comes to rest, hanging in a vertical position as determined by gravity. The frequency with which the pendulum oscillates is referred to as its “natural frequency”. </p>
<p>From experience, we also know that if we want to keep the pendulum oscillating, the easiest way to do this is by giving it a helpful nudge every time it reaches the highest point of its oscillation, just as we do when we push a child higher on a swing. When we do this, we are allowing the pendulum or swing to “resonate”.</p>
<p>So, resonance occurs when an external force affects a system at its natural frequency, causing the system to achieve larger amplitude oscillations at a fraction of the force needed. That’s what makes operating at resonance so efficient. We applied the same principle to the propulsion of our jellyfish-inspired robot. </p>
<p>We hypothesised that by designing a robot jellyfish with an elastic propulsive system, we could exploit the inherent natural frequency of that elastic to drive the mechanism into resonance. In resonance, our robot would issue powerful pulsed jets at a fraction of the energy cost.</p>
<p>The robot we developed has an elastic inner chamber, which expands and collapses under the effect of an umbrella-like mechanism. When tested in a water tank, the robot was found to increase its swimming speed as the speed at which it pulsed approached the natural frequency of the robot jellyfish’s elastic chamber. It proved that our robot jellyfish had achieved resonance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ty3A4PyAPrk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In this experiment, we show how our robotic jellyfish swims faster the closer it gets to achieving resonance.</span></figcaption>
</figure>
<p>The efficiency of a system that propels itself, be it mechanical or biological, is based on an equation that combines the power absorbed, the speed of the system and its mass. When applied to our robot, that equation put our robot jellyfish on par with the <em>Aurelia aurita</em> jellyfish.</p>
<p>This is a striking result with a twofold impact. On one hand, it shows for the first time that a mechanical system can achieve the propulsive efficiency of the best of nature’s swimmers. On the other hand, our robot has explained the outstanding swimming of its biological counterparts – which may now help biologists return to the study of jellyfish and squid with an entirely new perspective.</p>
<p>Powered by a system inspired by the most efficient of nature’s swimmers, our robot jellyfish provides a prototype of a dynamic and efficient underwater robot, which the offshore windfarm industry may one day use to maintain the parts of their infrastructure that lie beneath the waves.</p>
<p><em>This article was updated on February 24 2021 to credit the team from the University of Southampton who also worked on this research.</em></p><img src="https://counter.theconversation.com/content/154766/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Francesco Giorgio-Serchi works for the University of Edinburgh. He received funding from the Natural Environment Research Council. </span></em></p>The new underwater robots successfully mimic the sea’s most efficient swimmers.Francesco Giorgio-Serchi, Chancellor's Fellow in Robotics and Autonomous Systems, The University of EdinburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1498312020-11-11T19:20:12Z2020-11-11T19:20:12ZThis super rare squid is a deep-sea mystery. We recently spotted not 1, but 5, in the Great Australian Bight<figure><img src="https://images.theconversation.com/files/368782/original/file-20201111-19-1lvqyh3.png?ixlib=rb-1.1.0&rect=0%2C0%2C1581%2C1457&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Osterhage et al.</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The mysterious bigfin squid has been spotted in Australia’s waters for the first time. My colleagues and I from the CSIRO and Museums Victoria detail the encounters in our new research, published today in <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0241066">Public Library of Sciences ONE</a>. </p>
<p>There have only been about a dozen bigfin squid sightings worldwide over the past two decades. Ours happened more than two kilometres below the ocean’s surface in the Great Australian Bight, off the coast of South Australia.</p>
<p>For many people, the phrase “deep-sea squid” may conjure up images of the giant squid, <em>Architeuthis dux</em>, or <a href="https://theconversation.com/the-real-life-origins-of-the-legendary-kraken-52058">krakens</a> with huge tentacles swimming in inky black water. </p>
<p>But there are dozens, if not hundreds, of other species of deep-sea squid and octopus (both members of the class Cephalopoda) that are just as mysterious.</p>
<h2>First encounters with a slippery individual</h2>
<p>For years, one of the only ways to sample the deep sea was to trawl the sea floor with nets. This often damaged the soft bodies of deep-sea organisms beyond recognition. These mangled specimens are then difficult to identify and reveal little to nothing about the creatures. </p>
<p>Fortunately, newer technologies such as remotely-operated vehicles (ROVs) equipped with high-definition cameras are letting scientists see species as they’ve never seen before — offering deeper insight into their shapes, colours and behaviours in the wild.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bigfin squid, _Magnapinna_" src="https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1785&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1785&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368783/original/file-20201111-23-s7a4xm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1785&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Magnapinna</em> is a member of the Cephalopoda class, which includes octopuses and cuttlefish.</span>
<span class="attribution"><span class="source">Osterhage et al.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The enigmatic bigfin squid, <em>Magnapinna</em>, is one case in point. When scientists <a href="https://www.tandfonline.com/doi/abs/10.2989/025776198784126340">first described the species in 1998</a>, all they had to go by were some damaged specimens from Hawaii.</p>
<p>The most distinctive feature of these specimens were the large fins (at the very top of the body), which gave the squid its name. Years later, scientists exploring the deep Gulf of Mexico with ROVs realised they had come across <em>Magnapinna</em> in the wild. </p>
<p>They discovered that in addition to its distinctive fins, its arms had incredibly long filaments on the tips, making the bigfin squid unlike any other encountered. </p>
<p>These delicate filaments, which are mostly broken off in collected specimens, give <em>Magnapinna</em> an estimated total length of up to seven meters!</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tE9BooBvpwc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In 2001, scientists exploring the seafloor off Oahu, Hawaii, captured footage of a bigfin squid estimated to be between four and six metres long.</span></figcaption>
</figure>
<h2>Mysterious critters and where to find them</h2>
<p>But despite deep-sea ROV surveys becoming more common, <em>Magnapinna</em> has remained elusive. </p>
<p>The handful of sightings have been as far apart as the Central Pacific, North and South Atlantic, Gulf of Mexico and Indian Ocean. This suggests a worldwide distribution. </p>
<p>Yet, the big fin squid had never been seen in Australian waters. That is, until recently, when our team took part in a major research project to better understand the biology and geology of the Great Australian Bight, through the Great Australian Bight Deepwater Marine Program.</p>
<p>On the CSIRO’s research vessel <a href="https://www.csiro.au/en/Research/Facilities/MNF/RV-Investigator"><em>Investigator</em></a> and charter vessel <em>REM Etive</em>, we surveyed as deep as five kilometres below the water’s surface. Using nets, ROVs and other camera equipment, we recorded hundreds of hours of video footage and uncovered thousands of species.</p>
<p>On one dive, as we watched the video feed from cameras far below us, a wispy shape emerged from the gloom. With large undulating fins, a small torpedo-shaped body and long stringy limbs, it was unmistakably <em>Magnapinna</em>. We yelled and brought the ROV to a halt to get a better look.</p>
<p>The meeting lasted about three minutes. During this time we managed to use parallel laser pointers to measure the squid’s length — about 1.8 meters — before it swam away into darkness.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/octopuses-are-super-smart-but-are-they-conscious-57846">Octopuses are super-smart ... but are they conscious?</a>
</strong>
</em>
</p>
<hr>
<p>In total, we recorded five encounters with <em>Magnapinna</em> in the Great Australian Bight. Based on the animals’ measurements, we believe we recorded five different individuals: the most <em>Magnapinna</em> ever filmed in one place. </p>
<p>Most previous records have been of single <em>Magnapinna</em>, but our five squid were all found clustered close to each other. This might mean they like the habitat where they were found, but we’ll need more sightings to be sure.</p>
<h2>Unexplained behaviours</h2>
<p>The footage we captured has offered new information about <em>Magnapinna</em>’s ecology, behaviour and anatomy.</p>
<p>Previously, <em>Magnapinna</em> has been seen many meters off the sea floor in an upright posture, with arms held wide and filaments draping down. We’re not sure what the specific function of this behaviour is. It might be a way to find prey — akin to dangling sticky, sucker-covered fishing lines.</p>
<p>On our voyage, we saw the squid in a horizontal version of this pose, just centimetres off the sea floor, with its arms and filaments streaming behind. Again, we don’t know whether this behaviour is for travelling, avoiding predators or another method of searching for prey.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368722/original/file-20201110-23-14l4aet.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">If you look at this photo carefully, you can a bigfin squid with its arms spread wide, and its filaments as faint lines stretching away to the bottom right.</span>
<span class="attribution"><span class="source">Osterhage et al.</span></span>
</figcaption>
</figure>
<p>One near-miss with a camera gave us a very closeup image of <em>Magnapinna</em> which showed filaments that appeared to be coiled like springs. This may be a means for <em>Magnapinna</em> to retract its filaments when needed, perhaps if it wanted to avoid damage, or reel in something it caught.</p>
<p>Until now, only one other cephalopod, the vampire squid (<em>Vampyroteuthis infernalis</em>), has been known to coil its filamentous appendages this way.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368721/original/file-20201110-17-1blnogq.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">A close encounter just centimetres off the seabed shows the squid in a horizontal posture, with its arms spread and filaments dragging behind. Curiously, some of the filaments appear to be coiled like springs.</span>
<span class="attribution"><span class="source">Osterhage et al.</span></span>
</figcaption>
</figure>
<p>We have learned more about the mysterious bigfin squid. But until we have more sightings, or even an intact specimen, questions will remain. </p>
<p>One thing we do know is ROV surveying has great potential to enhance our understanding of deep-sea animals. With so much of the ocean around Australia yet to be explored, who knows what we’ll see coming out of the gloom next time?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-have-people-ever-seen-a-colossal-squid-137398">Curious Kids: have people ever seen a colossal squid?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/149831/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Funding for this research was provided through the Great Australian Bight Deepwater Marine Program, a CSIRO led research program sponsored by Chevron Australia, with data generated to be made publicly available.</span></em></p><p class="fine-print"><em><span>Deborah Osterhage 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 recorded the largest number of bigfin squids ever seen in one area. Before this, this rather elongated creature had only been spotted a dozen times across the globe.Hugh MacIntosh, Research Associate, Marine Invertebrates, Museums Victoria Research InstituteDeborah Osterhage, Marine Scientist, Oceans and Atmosphere, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1487722020-10-27T21:12:37Z2020-10-27T21:12:37ZGiant ‘toothed’ birds flew over Antarctica 40 million to 50 million years ago<figure><img src="https://images.theconversation.com/files/365550/original/file-20201026-21-t2z6hk.png?ixlib=rb-1.1.0&rect=9%2C14%2C3249%2C2013&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fossil remains indicate these birds had a wingspan of over 20 feet.</span> <span class="attribution"><span class="source">Brian Choo</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>Picture Antarctica today and what comes to mind? Large ice floes bobbing in the Southern Ocean? Maybe a remote outpost populated with scientists from around the world? Or perhaps colonies of penguins puttering amid vast open tracts of snow?</p>
<p>Fossils from Seymour Island, just off the Antarctic Peninsula, are painting a very different picture of what Antarctica looked like 40 to 50 million years ago – a time when the ecosystem was lusher and more diverse. Fossils of <a href="https://doi.org/10.1038/s41598-020-61973-5">frogs</a> and <a href="https://doi.org/10.1080/03115518.2011.565214">plants</a> such as ferns and conifers indicate Seymour Island was much warmer and less icy, while fossil remains from <a href="https://doi.org/10.7717/peerj.8268">marsupials and distant relatives of armadillos and anteaters</a> hint at the previous connections between Antarctica and other continents in the Southern Hemisphere.</p>
<p>There were also birds. Penguins were present then, as they are now, but fossil relatives of <a href="http://dx.doi.org/10.13679/j.advps.2019.0014">ducks, falcons and albatrosses</a> have also been found in Antarctica. My <a href="https://scholar.google.com/citations?user=5CGShQUAAAAJ&hl=en&oi=ao">colleagues</a> and <a href="https://scholar.google.com/citations?user=XlyfD9QAAAAJ&hl=en&oi=ao">I</a> published an <a href="https://doi.org/10.1038/s41598-020-75248-6">article in 2020</a> revealing new information about the fossil group that would have dwarfed all the other birds on Seymour Island: the pelagornithids, or “bony-toothed” birds. </p>
<h2>Giants of the sky</h2>
<p>As their name suggests, these ancient birds had sharp, bony spikes protruding from sawlike jaws. Resembling teeth, these spikes would have helped them catch squid or fish. We also studied another remarkable feature of the pelagornithids – their imposing size.</p>
<p>The largest flying bird alive today is the <a href="https://www.nationalgeographic.com/animals/birds/group/albatrosses/">wandering albatross</a>, which has a wingspan that reaches 11 ½ feet. The Antarctic pelagornithids fossils we studied have a wingspan nearly double that – about 21 feet across. If you tipped a two-story building on its side, that’s about 20 feet.</p>
<p>Across Earth’s history, very few groups of vertebrates have achieved powered flight – and only two reached truly giant sizes: birds and a group of <a href="https://www.amnh.org/exhibitions/pterosaurs-flight-in-the-age-of-dinosaurs/what-is-a-pterosaur">reptiles called pterosaurs</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A model of an enormous prehistoric bird is mounted outdoor in the middle of a river. The wingspan reaches from bank to bank." src="https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365561/original/file-20201026-23-p2l76b.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">Full-size model of a Quetzalcoatlus on display at JuraPark in Baltow, Poland.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/5/5c/Kecalkoatl_%28Quetzalcoatlus%29_-_Baltow_%281%29.JPG">Aneta Leszkiewicz/Wikimedia</a></span>
</figcaption>
</figure>
<p>Pterosaurs ruled the skies during the Mesozoic Era (252 million to 66 million years ago), the same period that dinosaurs roamed the planet, and they reached hard-to-believe dimensions. <a href="https://www.wired.com/2013/11/absurd-creature-of-the-week-quetz/">Quetzalcoatlus</a> stood 16 feet tall and had a colossal 33-foot wingspan.</p>
<h2>Birds get their opportunity</h2>
<p>Birds originated while dinosaurs and pterosaurs were still roaming the planet. But when an <a href="https://www.smithsonianmag.com/science-nature/dinosaur-killing-asteroid-impact-chicxulub-crater-timeline-destruction-180973075/">asteroid struck the Yucatan Peninsula 66 million years ago</a>, dinosaurs and pterosaurs both perished. Some <a href="https://www.audubon.org/news/how-birds-survived-asteroid-impact-wiped-out-dinosaurs">select birds survived</a>, though. These survivors diversified into the thousands of bird species alive today. Pelagornithids evolved in the period right after dinosaur and pterosaur extinction, when competition for food was lessened. </p>
<p><a href="https://doi.org/10.1002/spp2.1284">The earliest pelagornithid remains</a>, recovered from 62-million-year-old sediments in New Zealand, were about the size of modern gulls. The first giant pelagornithids, the ones in our study, <a href="https://doi.org/10.1038/s41598-020-75248-6">took flight over Antarctica about 10 million years later</a>, in a period called the Eocene Epoch (56 million to 33.9 million years ago). In addition to these specimens, fossilized remains from other pelagornithids have been found on every continent. </p>
<p>Pelagornithids lasted for about 60 million years before going extinct just before the Pleistocene Epoch (2.5 million to 11,700 years ago). No one knows exactly why, though, because few fossil records have been recovered from the period at the end of their reign. Some paleontologists cite <a href="https://doi.org/10.1080/02724634.2011.562268">climate change as a possible factor</a>.</p>
<h2>Piecing it together</h2>
<p>The fossils we studied are fragments of whole bones collected by paleontologists from the University of California at Riverside in the 1980s. In 2003, the specimens were transferred to Berkeley, where they now reside in the <a href="https://ucmp.berkeley.edu/">University of California Museum of Paleontology</a>. </p>
<p>There isn’t enough material from Antarctica to rebuild an entire skeleton, but by comparing the fossil fragments with similar elements from more complete individuals, we were able to assess their size. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of a fossil fragment of a jawbone section that has worn toothlike projections. Line drawing around it illustrates where in the jaw it would have fit." src="https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=573&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=573&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=573&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=720&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=720&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365552/original/file-20201026-17-1koc1h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=720&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In life, the pelagornithid would have had numerous ‘teeth,’ making it a formidable predator.</span>
<span class="attribution"><span class="source">Peter Kloess</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>We estimate the pelagornithid’s skull would have been about 2 feet long. A fragment of one bird’s lower jaw preserves some of the “pseudoteeth” that would have each measured up to an inch tall. The spacing of those “teeth” and other measurements of the jaw show this fragment came from an individual as big as, if not bigger than, the largest known pelagornithids. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<p>Further evidence of the size of these Antarctic birds comes from a second pelagornithid fossil, from a different location on Seymour Island. A section of a foot bone, called a tarsometatarsus, is the largest specimen known for the entire extinct group. </p>
<p>These pelagornithid fossil findings emphasize the importance of natural history collections. Successful field expeditions result in a wealth of material brought back to a museum or repository – but the time required to prepare, study and publish on fossils means these institutions typically <a href="https://theconversation.com/digitizing-the-vast-dark-data-in-museum-fossil-collections-102833">hold many more specimens than they can display</a>. Important discoveries can be made by collecting specimens on expeditions in remote locations, no doubt. But equally important discoveries can be made by simply processing the backlog of specimens already on hand.</p><img src="https://counter.theconversation.com/content/148772/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter A. Kloess 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>Paleontologists have discovered fossil remains belonging to an enormous ‘toothed’ bird that lived for a period of about 60 million years after dinosaurs.Peter A. Kloess, Doctoral Candidate, Integrative Biology, University of California, BerkeleyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1373982020-05-01T02:41:23Z2020-05-01T02:41:23ZCurious Kids: have people ever seen a colossal squid?<figure><img src="https://images.theconversation.com/files/331312/original/file-20200429-51480-1l700dw.jpg?ixlib=rb-1.1.0&rect=96%2C75%2C7052%2C3644&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Robson, 1925, collected 2008, Ross Sea, Antarctica. Gift of the Ministry of Fisheries, 2007. Te Papa (M.190318)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><blockquote>
<p>Have people ever seen a colossal squid? – Aubree</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>The colossal squid (<em>Mesonychoteuthis hamiltoni</em>) is the stuff of nightmares ripped straight out of the mind of a sleeping pirate. Picture the <a href="https://theconversation.com/the-real-life-origins-of-the-legendary-kraken-52058">giant kraken</a> wrapped around a ship and dragging it to the bottom of the sea!</p>
<p>People have seen colossal squid, but not very often. Colossal squid live in the Southern Ocean near Antarctica, and it was not until 1981 when the first whole animal was found. It was captured by a trawler near the coast of Antarctica. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331285/original/file-20200429-51474-1rh5x9y.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">A drawing from 1810 of the kraken sinking a merchant ship.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>Since then a few more have been captured by fishermen. You can see one today in a <a href="https://www.tepapa.govt.nz/discover-collections/read-watch-play/science/colossal-squid">New Zealand museum</a>, but they do not preserve well.</p>
<p>Colossal squid are the heaviest squid on the planet (but they’re not actually big enough to sink a pirate ship). The ones that have been found whole weighed nearly 500 kilograms – that’s almost the same as a grand piano.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-is-the-sea-salty-124743">Curious Kids: why is the sea salty?</a>
</strong>
</em>
</p>
<hr>
<p>But judging by the size of the squid beaks that have been found in the stomach of sperm whales, they can get a lot bigger. It is estimated they can weigh up to 700kg!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331302/original/file-20200429-51513-wtnpaa.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">A close-up of the colossal squid specimen.</span>
<span class="attribution"><span class="source">Robson, 1925, collected 2003, Ross Sea, Antarctica. Te Papa (M.160614)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Colossal squid might be heavy, but they may not be the longest squid in the world. They likely grow to around 10 metres long, which is still less than the giant squid, which can grow to more than 12 metres long. The giant squid has a smaller body and really long tentacles, so it doesn’t weigh as much.</p>
<p>They have huge eyes which can be 25 centimetres or more in diameter (as big as a soccer ball). That makes them the biggest animal eyes on the planet. Their eyes have built in headlights that help them see in the dark. </p>
<p>They are set slightly forward-facing so the colossal squid has “binocular vision”. This means it can judge distances when capturing prey. Their tentacles are armed with rotating hooks that allow them to grasp their prey.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-do-sharks-sneeze-77399">Curious Kids: Do sharks sneeze?</a>
</strong>
</em>
</p>
<hr>
<p>Colossal squid are thought to feed mostly on fish and other squid in the deep parts of the Southern Ocean (more than 1,000 metres deep). At that depth, there is no sunlight and they might use light that can shine from their body (<a href="https://ocean.si.edu/ocean-life/fish/bioluminescence">bioluminescence</a>) to lure their prey. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ug0p7Np56fM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Like all squid, they have a hard beak like a bird, which they use to munch their food. The beak is the only hard part of the squid’s body.</p>
<p>Would such a big animal actually be afraid of anything? Sperm whales are their major predator. It has been estimated that more than 75% of the diet of sperm whales is made up of colossal squid. That is a LOT of calamari! </p>
<p>Many sperm whales have scars on their bodies, caused by epic battles with colossal squid. </p>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/137398/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Culum Brown currently receives funding from the Australian Research Council. </span></em></p>Colossal squid have eyes the size of soccer balls, and can weigh up to 700kg. That’s a lot of calamari!Culum Brown, Professor, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/756952017-04-23T20:02:17Z2017-04-23T20:02:17ZBigfoot, the Kraken and night parrots: searching for the mythical or mysterious<figure><img src="https://images.theconversation.com/files/166229/original/file-20170421-12655-110r77u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In 2012 scientists succeeded in filming for the first time ever a giant squid in its natural habitat.</span> <span class="attribution"><span class="source">EPA/NHK/NEP/DISCOVERY CHANNEL/AAP</span></span></figcaption></figure><p>It’s remarkable how little we know about Earth. How many species do we share this planet with? We don’t know, but estimates vary from <a href="http://www.livescience.com/54660-1-trillion-species-on-earth.html">millions to a trillion</a>. In some respects we know more about the Moon, Mars and Venus than we do about the ocean’s depths and the <a href="https://theconversation.com/just-how-little-do-we-know-about-the-ocean-floor-32751">vast sea floors</a>. </p>
<p>But humans are inquisitive creatures, and we’re driven to explore. Chasing mythical or mysterious animals grabs media headlines and <a href="https://theconversation.com/cryptozoology-no-need-for-an-apology-12332">spurs debates</a>, but it can also lead to remarkable discoveries. </p>
<p>The recent photographing of a live <a href="https://theconversation.com/still-here-night-parrot-rediscovery-in-wa-raises-questions-for-mining-75384">night parrot</a> in Western Australia brought much joy. These enigmatic nocturnal birds have been only sporadically sighted over decades.</p>
<p>Another Australian species that inspires dedicated searchers is the Tasmanian tiger, or thylacine. A <a href="http://www.abc.net.au/news/2017-03-24/tasmanian-tiger-sightings-spark-scientific-study/8383884">new hunt</a> is under way, not in Tasmania but in Queensland’s vast wilderness region of Cape York. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166236/original/file-20170421-12655-1gh7pi.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">This is the first photograph of a live night parrot, taken in Western Australia in March 2017.</span>
<span class="attribution"><span class="source">Bruce Greatwitch</span></span>
</figcaption>
</figure>
<p>Other plans are afoot to search for the <a href="http://www.australiangeographic.com.au/news/2017/04/researchers-to-search-for-ancient-%E2%80%98extinct%E2%80%99-echidna?adbsc=social_20170404_71301076&adbid=10154476450238339&adbpl=fb&adbpr=100614418338">long-beaked echidna</a> in Western Australia’s Kimberley region. </p>
<p>In the case of the thylacine, <a href="http://trove.nla.gov.au/work/182690697?selectedversion=NBD51749461">old accounts</a> from the region that sound very much like descriptions of the species raise the prospect that perhaps Cape York isn’t such a bad place to look after all. </p>
<p>But in reality, and tragically, it’s very unlikely that either of these species still survives in Australia. For some species there is <a href="http://onlinelibrary.wiley.com/doi/10.1111/gcb.13421/epdf">scientific research</a> that estimates just how improbable such an event would be; in the case of thylacines, one model suggests the odds are <a href="https://www.newscientist.com/article/2128077-odds-that-tasmanian-tigers-are-still-alive-are-1-in-1-6-trillion/?utm_term=Autofeed&utm_campaign=Echobox&utm_medium=Social&cmpid=SOC%7CNSNS%7C2017-Echobox&utm_source=Twitter#link_time=1492680136">1 in 1.6 trillion</a>. </p>
<h2>Chasing myths</h2>
<p>The study and pursuit of “hidden” animals, thought to be extinct or fictitious, is often called cryptozoology. The word itself invites scorn – notorious examples include the search for Bigfoot, the <a href="https://en.wikipedia.org/wiki/Loch_Ness_Monster">Loch Ness Monster</a> or Victoria’s legendary <a href="http://www.heraldsun.com.au/news/national/big-cat-hunt-declared-over-by-victorian-government-due-to-lack-of-evidence/news-story/0886b66e8c33f80036a5716634dad456?sv=daff6daf5f09e0747b704e9c5ef430e7">black panthers</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/v77ijOO8oAk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The search for Bigfoot is an extreme case of cryptozoology.</span></figcaption>
</figure>
<p>Granted, it’s probably apt to describe those searches as <a href="https://theconversation.com/the-bigger-the-bigfoot-claim-the-bigger-the-need-for-evidence-12245">wild goose chases</a>, but we must also acknowledge that genuine species – often quite sizeable ones – have been discovered.</p>
<p><a href="https://blogs.scientificamerican.com/tetrapod-zoology/shuker-encyclopaedia-of-new-and-rediscovered-animals/">Remarkable discoveries</a> of animals thought to be fantasies or long extinct include <a href="https://www.ted.com/talks/edith_widder_how_we_found_the_giant_squid">giant squid</a>, <a href="http://www.nationalgeographic.com/animals/mammals/m/mountain-gorilla/">mountain gorillas</a>, <a href="https://en.wikipedia.org/wiki/Okapi">okapi</a>, <a href="http://www.nationalgeographic.com/animals/reptiles/k/komodo-dragon/">Komodo dragons</a> and <a href="http://animals.nationalgeographic.com.au/animals/fish/coelacanth/">coelacanths</a>. </p>
<p>In some cases, like the giant squid, these animals have been dismissed as legends. The <a href="http://news.nationalgeographic.com/2017/02/pictures-oarfish-philippines/">reclusive oarfish</a>, for example, are thought to be the inspiration for centuries of stories about sea serpents. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166233/original/file-20170421-12633-f2gpiy.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"></a>
<figcaption>
<span class="caption">Oarfish can grow up to 8 metres long and swim vertically through the water. Commonly inhabiting the deep ocean, they occasionally come to shallow water for unknown reasons.</span>
<span class="attribution"><span class="source">AAP Image/ Coastal Otago District Office</span></span>
</figcaption>
</figure>
<h2>Technology to the rescue</h2>
<p>Finding rare and cryptic species is self-evidently challenging, but rapid advances in technology open up amazing possibilities. Camera traps now provide us with regular selfies of once highly elusive snow leopards, and could equally be used with other difficult-to-find animals. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/onNahCXzONc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Candid camera, snow leopards in the Himalayas.</span></figcaption>
</figure>
<p><a href="https://theconversation.com/fishing-for-dna-free-floating-edna-identifies-presence-and-abundance-of-ocean-life-75957">Environmental DNA</a> is allowing us to detect species otherwise difficult to observe. Animal DNA found in the <a href="http://onlinelibrary.wiley.com/doi/10.1002/bies.201300060/abstract">blood of leeches</a> has uncovered <a href="https://news.mongabay.com/2012/04/does-the-tasmanian-tiger-exist-is-the-saola-extinct-ask-the-leeches/">rare and endangered mammals</a>, meaning these and other much maligned blood-sucking parasites could be powerful biodiversity survey tools.</p>
<p><a href="https://theconversation.com/why-conservation-scientists-are-listening-to-nature-73397">Acoustic recording devices</a> can be left in areas for extended time periods, allowing us to eavesdrop on ecosystems and look out for sounds that might indicate otherwise hidden biological treasures. And coupling drones with thermal sensors and high resolution cameras means we can now take an eagle eye to remote and challenging environments. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FIrgjCNcDBI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Drones are opening up amazing possibilities for biological survey and wildlife conservation.</span></figcaption>
</figure>
<h2>The benefits of exploration and lessons learned</h2>
<p>It’s easy to criticise the pursuit of the unlikely, but “miracles” can and do occur, sometimes on our doorstep. The discovery of the <a href="https://theconversation.com/where-the-old-things-are-australias-most-ancient-trees-65893">ancient Wollemi pine</a> is a case in point. Even if we don’t find what we’re after, we may still benefit from what we learn along the way. </p>
<p>I’ve often wondered how many more species might be revealed to us if scientists invested more time in carefully listening to, recording and following up on the knowledge of Indigenous, farming, and other communities who have long and intimate associations with the land and sea. </p>
<p>Such an approach, combined with the deployment of new technologies, could create a boom of biological discovery.</p><img src="https://counter.theconversation.com/content/75695/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Euan Ritchie receives funding from the Australian Research Council. Euan Ritchie is a Director (Media Working Group) of the Ecological Society of Australia, and a member of the Australian Mammal Society.</span></em></p>Searching for animals thought to be extinct – or fictional – is difficult, painstaking and often disappointing. But new technology like drones offer hope of a boom in biological discovery.Euan Ritchie, Senior Lecturer in Ecology, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/756632017-04-06T16:08:02Z2017-04-06T16:08:02ZOctopuses can defy their genetic instructions – and it’s slowed down their evolution<figure><img src="https://images.theconversation.com/files/164279/original/image-20170406-6391-64023x.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>Are octopuses so clever because they ignore their genetic programming? Research has shown that octopuses and other cephalopods edit the messages sent from their DNA instead of following them almost exactly like most living things usually do. </p>
<p>Previously, scientists thought this process of molecular Chinese whispers was largely insignificant in animal evolution. But a <a href="http://bit.ly/2oVKVk2">new study</a> published in the journal Cell shows this is certainly not true for these tentacled ocean dwellers. </p>
<iframe src="https://www.facebook.com/plugins/video.php?href=https%3A%2F%2Fwww.facebook.com%2FConversationUK%2Fvideos%2F740553626112980%2F&show_text=0&width=560" width="100%" style="border:none;overflow:hidden" scrolling="no" frameborder="0" allowtransparency="true" allowfullscreen="true" height="400"></iframe>
<p>It suggests that genetic editing may directly contribute to cephalopods’ remarkable intelligence, which enables them to <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152048">solve complicated puzzles</a> and visually communicate by <a href="http://rsbl.royalsocietypublishing.org/content/2/4/494">changing their skin colour</a>, making them the <a href="http://www.slate.com/articles/health_and_science/science/2008/06/how_smart_is_the_octopus.html">smartest of all invertebrates</a>. However, the ability to alter genetic messages may come at a price, potentially reducing other more common forms of adaptive evolution. </p>
<p>DNA is the blueprint of life. This genetic instruction manual is written in a four-letter language and describes how to build all the different proteins an organism can construct. To synthesise a particular protein, an enzyme first transcribes the recipe from DNA into a message in a similar molecule called RNA. Part of this message is eventually translated into chains of amino acids, the building blocks of protein.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164314/original/image-20170406-16671-ruun1t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Doryteuthis pealeii</em></span>
<span class="attribution"><span class="source">Roger Hanlon, Marine Biological Laboratory</span></span>
</figcaption>
</figure>
<p>For most organisms, including humans, the whole process of protein synthesis remains remarkably faithful to the original instructions laid out in the DNA. This premise has underpinned much of our understanding of genetics since we discovered that genetic information is stored as DNA. But recent research has shown that octopuses, squid, and cuttlefish <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4208822/">do not always follow</a> their genetic instructions to the letter.</p>
<p>After the RNA message is copied accurately from the DNA, it can be altered in a process called RNA editing. This edited message then produces proteins that also have modifications. RNA editing was <a href="http://www.sciencedirect.com/science/article/pii/0092867486900632?via=ihub">first described in 1986</a> by researchers studying single-celled parasites closely related to the microbe responsible for causing sleeping sickness.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164321/original/image-20170406-16665-1epqq7v.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Sepia officinalis</em></span>
<span class="attribution"><span class="source">Roger Hanlon, Marine Biological Laboratory</span></span>
</figcaption>
</figure>
<p>Since then, RNA editing has been seen as relatively unimportant in animals. Humans, for example, have <a href="genome.cshlp.org/content/24/3/365.long">only a handful</a> of RNA editing sites in their protein coding sequences. What’s more, the changes from RNA editing we knew about were thought to have little effect, and very few of them were shared across groups of closely related species, <a href="https://genomebiology.biomedcentral.com/articles/10.1186/gb-2014-15-1-r5">including mammals</a>. </p>
<p>However, in the remarkably intelligent squid, RNA editing <a href="https://elifesciences.org/content/4/e05198">affects most genes</a> associated with the nervous system. This suggests that, in certain groups of organisms, the practice may play an important role. By comparing how often RNA editing occurs within the cephalopod family, <a href="http://bit.ly/2oVKVk2">the new study</a> identified when in evolutionary history this ability to alter genetic messages appeared.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IvvjcQIJnLg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The researchers showed that widespread RNA editing evolved in the common ancestor of the exceptional behaviourally sophisticated octopuses, squid and cuttlefish. And that it is lacking in the relatively simple-minded nautilus, a more distant relative. Because neural proteins exhibit some of the most intensive RNA editing, the researchers suggest that this process may contribute to cephalopods’ remarkable intelligence. </p>
<p>RNA editing is thought to give cephalopods an evolutionary advantage by increasing the variation in the proteins they produce. This enables them to rapidly adapt to changing environments. For example, we know RNA editing allows octopuses to deal with <a href="http://science.sciencemag.org/content/335/6070/848">dramatic changes in temperature</a> and so survive in frigid polar waters.</p>
<h2>Trade-off</h2>
<p>But this recent study also suggests that there may be a trade-off between this ability to adapt quickly and the long-term process of Darwinian DNA evolution.</p>
<p>RNA editing is performed by an enzyme, and this enzyme requires a specific target site written into the genetic code. This long stretch of molecules surrounds the point in the RNA message that needs editing. Any mutation in this target marker will disrupt the whole process, and the enzyme will no longer be able to edit the RNA message. To avoid this, cephalopods have evolved DNA that is less likely to mutate.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164317/original/image-20170406-16671-1r9x65g.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"><em>Octopus bimaculoides</em></span>
<span class="attribution"><span class="source">Tom Kleindinst, Marine Biological Laboratory</span></span>
</figcaption>
</figure>
<p>However, mutation is the basis for conventional molecular DNA evolution and is needed to permanently change the code for a protein in a way that improves its function. So the prevalence of RNA editing in cephalopods appears to have substantially limited its potential for adaptive DNA evolution. This pattern may go some way towards explaining why this process is not more prevalent across the animal kingdom.</p>
<p>The widespread use of RNA editing in cephalopods means we may have to rethink our understanding of its importance in nature. In the case of cephalopods, the ink the DNA instructions are written in appears to be less permanent than we originally thought.</p><img src="https://counter.theconversation.com/content/75663/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Dunning does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new study shows cephalopods edit messages from their DNA, allowing them to adapt faster to their environment.Luke Dunning, Postdoctoral research associate, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/598302016-05-24T16:16:42Z2016-05-24T16:16:42ZOctopus and squid populations are booming – here’s why<figure><img src="https://images.theconversation.com/files/123793/original/image-20160524-25218-2z2w2b.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">Kristina Vackova / shutterstock</span></span></figcaption></figure><p>Squid, octopus and cuttlefish populations are booming across the world. These fast-growing, adaptable creatures are perfectly equipped to exploit the gaps left by extreme climate changes and overfishing, according to a study colleagues and I published in the journal <a href="http://www.sciencedirect.com/science/journal/09609822">Current Biology</a>.</p>
<p>Humans have reached and in many cases surpassed sustainable fishing limits, as our growing population demands more food. In terms of the food web, we tend to start from the top and fish “<a href="http://science.sciencemag.org/content/279/5352/860">downwards</a>”. Fishermen fish out the top predators first, including large sharks, tuna and whales, and then medium size fish such as cod, hake and halibut that usually live long and grow slowly.</p>
<p>The vacant space left by fish may be occupied by other species, with rapidly proliferating animals having a clear advantage. And these animals are cephalopods. Squid, octopus and cuttlefish live in the “fast lane”, growing quickly and typically living for only one or two years. They produce lots of eggs, and their eggs have <a href="http://onlinelibrary.wiley.com/book/10.1002/9780470995310">relatively low mortality rates</a>, whether thanks to patient brooding by an octopus mother or the protective mucous that covers embryonic squid. These traits enable cephalopods to adapt rapidly to changes in the environment which have become even more pronounced in recent decades thanks to human activity.</p>
<h2>Counting cephalopods</h2>
<p>These are elusive creatures, notoriously difficult to count. To get a better estimate of their overall abundance, we looked at what we call catch rates – how many were caught per vessel per unit of time – over the past six decades. We used an extensive dataset of 35 different species (52% squid, 31% octopus and 17% cuttlefish) from all major oceanic regions. Most were “target” species deliberately sought by fishermen, others were non-target or bycatch species. We used data from both regular commercial fisheries and specific research surveys.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/123797/original/image-20160524-25226-mh252c.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"></a>
<figcaption>
<span class="caption">A big fan of overfishing.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/oceanexplorergov/11195946184/">NOAA Ocean Explorer</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Everywhere we looked we found a substantial and statistically significant increase. Bottom-dwelling octopus and cuttlefish who live relatively static lives are thriving, as are squid that hover over the bottom, along with those in the open ocean that may travel thousands of kilometres from spawning to feeding sites. At a time when life in the oceans is <a href="http://science.sciencemag.org/content/347/6219/1255641">threatened</a>, cephalopods seem able to buck the trend.</p>
<h2>Extreme climate changes lead to population explosion</h2>
<p>The “jumbo squid” represents one of the most striking examples. Also known as the Humboldt squid, it typically weighs around 1-2 kg and has an annual life cycle. It lives in the warm waters of the eastern Pacific and has supported small-scale fishing in Mexico, Chile and <a href="https://www.sprfmo.int/assets/Meetings/Meetings-2013-plus/SC-Meetings/3rd-SC-Meeting-2015/Papers/SC-03-27-Biological-and-fishery-aspects-of-the-jumbo-squid-in-the-Peruvian-Humboldt-current.pdf">Peru</a>.</p>
<p>However, a strong hot season of El Niño followed by a cold season of La Niña can do funny things to these squid. The colder waters during a La Niña delay their maturation and allow them to survive into the next year, giving them a two-year life cycle. But during this second year they continue to grow fast meaning that by the end of their two years they attain much larger sizes. In fact, these climate events have triggered the establishment of large bi-annual groups of squid <a href="http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2014-0386">weighing 25-40 kg</a> – ten times their normal size. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/123796/original/image-20160524-25209-1svw1q2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A 24kg jumbo squid caught off the California coast.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Giant_Homboldt_squid.jpg">Fish guy</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>After the El Niño/La-Niña events of 1997-2000 these squid began to make their way <a href="http://www.pnas.org/content/104/31/12948.abstract">up the Pacific coast</a> to northern California reaching Alaska, leading to the recent development of one of the world’s largest squid fisheries. The total annual catch of <a href="http://www.tandfonline.com/doi/abs/10.1080/23308249.2015.1026226">600,000 to 1m tonnes</a> has become extremely important for coastal livelihoods of eastern Pacific countries.</p>
<p>However, as the jumbo squid’s “switch” from one to two year life cycles depends on ambient water temperature, another strong El Niño event may cause almost complete disappearance of the large group, returning the populations to their “normal condition” as a medium size annual breeder. This has happened recently in Mexico’s <a href="http://www.livescience.com/17088-vanishing-humboldt-squid.html">Gulf of California</a> causing havoc to local squid fisheries, and it may also happen in Peru and Chile, another region where a strong El-Niño event is currently occurring. </p>
<h2>Planet of the octopus?</h2>
<p>The boom in squid, octopus and cuttlefish will have interesting consequences both for their own ecosystem and for human society. On the one hand, it could benefit the sharks, whales and large fish which are reliant on them for food, along with certain fishermen.</p>
<p>However, cephalopod populations are much less stable than fish with longer lives. Usually they follow a “boom and bust” strategy, varying in biomass by <a href="http://www.sciencedirect.com/science/article/pii/S0967064512000896">several orders of magnitude</a> from year to year, changes that are notoriously difficult to predict. Fishing profits can vary hugely in line with fluctuating populations, and high conservation and economic risks are often exacerbated by the relative lack of co-operation and communication among industry participants. </p>
<p>As fisheries continue to refocus their efforts towards cephalopods, it becomes critically important to manage stocks appropriately so they do not face the same fate as many fish in the recent past.</p><img src="https://counter.theconversation.com/content/59830/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Arkhipkin is affiliated with Fisheries Department of the Falkland Islands. </span></em></p>Cephalopods are able to adapt rapidly to changing conditions.Alexander Arkhipkin, Honorary Research Fellow, School of Biological Sciences, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/520582015-12-30T10:42:46Z2015-12-30T10:42:46ZThe real-life origins of the legendary Kraken<figure><img src="https://images.theconversation.com/files/105272/original/image-20151210-7459-nachrx.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://commons.wikimedia.org/wiki/File:Giant_octopus_attacks_ship.jpg">Mary Evans Picture Library/Alamy</a></span></figcaption></figure><p>The Kraken is perhaps the largest monster ever imagined by mankind. In Nordic folklore, it was said to haunt the seas from Norway through Iceland and all the way to Greenland. The Kraken had a knack for harassing ships and many <a href="http://www.biodiversitylibrary.org/item/60177#page/391/mode/1up">pseudoscientific reports (including official naval ones)</a> said it would attack vessels with its strong arms. If this strategy failed, the beast would start swimming in circles around the ship, creating a fierce maelstrom to drag the vessel down.</p>
<p>Of course, to be worth its salt, a monster needs to have a taste for human flesh. <a href="http://www.biodiversitylibrary.org/item/131226#page/516/mode/1up">Legends</a> say that the Kraken could devour a ship’s entire crew at once. But despite its fearsome reputation, the monster could also bring benefits: it swam accompanied by huge schools of fish that cascaded down its back when it emerged from the water. Brave fishermen could thus risk going near the beast to secure a bounteous catch.</p>
<p>The <a href="http://www.scielo.br/pdf/hcsm/v21n3/0104-5970-hcsm-21-3-0971.pdf">history of the Kraken</a> goes back to an account written in 1180 by King Sverre of Norway. As with many legends, the Kraken started with something real, based on sightings of a real animal, the giant squid. For the ancient navigators, the sea was treacherous and dangerous, hiding a horde of monsters in its inconceivable depths. Any encounter with an unknown animal could gain a mythological edge from sailors’ stories. After all, the tale grows in the telling.</p>
<h2>Scientific legend</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/105269/original/image-20151210-7422-7i8rdd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Giant squid found in Ranheim, Norway, measured by Professors Erling Sivertsen and Svein Haftorn.</span>
<span class="attribution"><span class="source">NTNU Museum of Natural History and Archaeology, 1954</span></span>
</figcaption>
</figure>
<p>The strength of the myth became so strong that the Kraken could still be found in Europe’s <a href="http://www.biodiversitylibrary.org/bibliography/70332#/summary">first modern scientific surveys</a> of the natural world in the 18th century. Not even Carl Linnaeus – father of modern biological classification – could avoid it and he included the Kraken among the cephalopod mollusks in the first edition of his groundbreaking <a href="http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1359"><em>Systema Naturae</em></a> (1735).</p>
<p>But when, in 1853, a giant cephalopod was found stranded on a Danish beach, Norwegian naturalist Japetus Steenstrup recovered the animal’s beak and used it to <a href="https://books.google.dk/books?id=qzo4AAAAcAAJ&pg=PA182&hl=pt-BR#v=onepage&q&f=false">scientifically describe</a> the giant squid, <em>Architeuthis dux</em>. And so what had become legend officially entered the annals of science, returning our image of the Kraken to the animal that originated the myths.</p>
<p>After 150 years of research into the giant squid that inhabits all the world’s oceans, there is still much debate as to whether they represent a <a href="https://www.researchgate.net/publication/238390512_Giant_squid_beaks_Implications_for_systematics">single species or as many as 20</a>. The largest <em>Architeuthis</em> recorded reaches <a href="http://www.scientificamerican.com/article/the-giant-squid/">18 metres</a> in length, including the very long pair of tentacles, but the vast majority of specimens are much smaller. The giant squid’s eyes are the largest in the animal kingdom and are crucial in the dark depths it inhabits (up to 1,100 metres deep, perhaps reaching 2,000 metres).</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/9HGMxZEl60k?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Like some other squid species, <em>Architeuthis</em> has pockets in its muscles containing an ammonium solution that is less dense than sea water. This allows the animal to float underwater, meaning that it can keep itself steady without actively swimming. The presence of unpalatable ammonium in their muscles is also probably the reason why giant squid have not yet been fished to near extinction.</p>
<h2>Hunter or prey?</h2>
<p>For many years, scientists debated whether the giant squid was a swift and agile hunter like the powerful predator of legends or an ambush hunter. After decades of discussion, a welcome answer came in 2005 with the unprecedented film footage from Japanese researchers <a href="http://rspb.royalsocietypublishing.org/content/272/1581/2583">T. Kubodera and K. Mori</a>. They filmed a live <em>Architeuthis</em> in its natural habitat, 900m deep in the North Pacific, showing that it is in fact a fast and powerful swimmer, using its tentacles to capture prey.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/105271/original/image-20151210-7447-1jxt9s0.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">Reconstruction of an epic battle between a giant squid and its nemesis, the sperm whale.</span>
<span class="attribution"><span class="source">American Museum of Natural History.</span></span>
</figcaption>
</figure>
<p>Despite its size and speed, <em>Architeuthis</em> has a predator: the sperm whale. The battles between these titans must be frequent, since it is common to find scars on whales’ skins left by the squids’ tentacles and arms, which have suckers lined with sharp chitinous tooth-like structures. But <em>Architeuthis</em> doesn’t have the muscles in its tentacles to use them to constrict prey and it can never overcome a sperm whale in a “duel”. Its only option is to flee, covering its escape with the usual cephalopod ink cloud.</p>
<p>Although we now know it is not just a legend, the giant squid remains perhaps the most elusive large animal in the world, which has greatly contributed to its aura of mystery. Many people today are still surprised in learning that it really exists. After all, even after so much scientific research, the Kraken is still alive in popular imagination thanks to films, books and computer games, even if it sometimes turns up in the wrong mythology, such as the 1981 (and 2010) ancient Greek epic <em>Clash of the Titans</em>. These representations have come to define it in the public mind: a beast lurking in sunken ships waiting for reckless divers.</p><img src="https://counter.theconversation.com/content/52058/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rodrigo Brincalepe Salvador 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 myth of a monstrous giant squid prowling the oceans has persisted for centuries but scientists have been able to reveal the truth behind the stories.Rodrigo Brincalepe Salvador, PhD student in Paleontology, University of TübingenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/262652014-05-06T05:18:29Z2014-05-06T05:18:29ZHumans and squid evolved same eyes using same genes<figure><img src="https://images.theconversation.com/files/47660/original/cvwx3dzm-1399040861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">I see how you see.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/actor212/7841841370">actor212</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Eyes and wings are among the most stunning innovations evolution has created. Remarkably these features have evolved multiple times in different lineages of animals. For instance, the avian ancestors of birds and the mammalian ancestors of bats both evolved wings independently, in an example of convergent evolution. The same happened for the eyes of squid and humans. Exactly how such convergent evolution arises is not always clear.</p>
<p>In a new study, published in <a href="http://www.nature.com/srep/2014/140305/srep04256/full/srep04256.html?WT.ec_id=SREP-20140311">Nature Scientific Reports</a>, researchers have found that, despite belonging to completely different lineages, humans and squid evolved through tweaks to the same gene.</p>
<h2>Eyes are the prize</h2>
<p>Like all organs, the eye is the product of many genes working together. The majority of those genes provide information about how to make part of the eye. For example, one gene provides information to construct a light-sensitive pigment. Another gene provides information to make a lens.</p>
<p>Most of the genes involved in making the eye read like a parts list – this gene makes this, and that gene makes that. But some genes orchestrate the construction of the eye. Rather than providing instructions to make an eye part, these genes provide information about where and when parts need to be constructed and assembled. In keeping with their role in controlling the process of eye formation, these genes are called “master control genes”.</p>
<p>The most important of master control genes implicated in making eyes is called <em>Pax6</em>. The ancestral <em>Pax6</em> gene probably orchestrated the formation of a very simple eye – merely a collection of light-sensing cells working together to inform a primitive organism of when it was out in the open versus in the dark, or in the shade.</p>
<p>Today the legacy of that early <em>Pax6</em> gene lives on in an incredible diversity of organisms, from birds and bees, to shellfish and whales, from squid to you and me. This means the <em>Pax6</em> gene predates the evolutionary diversification of these lineages – during the Cambrian period, some 500m years ago.</p>
<p>The <em>Pax6</em> gene now directs the formation of an amazing diversity of eye types. Beyond the simple eye, it is responsible for insects’ compound eye, which uses a group of many light-sensing parts to construct a full image. It is also responsible for the type of eye we share with our vertebrate kin: camera eye, an enclosed structure with its iris and lens, liquid interior, and image-sensing retina.</p>
<p>In order to create such an elaborate structure, the activities <em>Pax6</em> controlled became more complex. To accommodate this, evolution increased the number of instructions that arose from a single <em>Pax6</em> gene.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.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">Complex beauty.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pacificklaus/8751081489">pacificklaus</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Making the cut</h2>
<p>Like all genes, the <em>Pax6</em> gene is an instruction written in DNA code. In order for the code to work, the DNA needs to be read and then copied into a different kind of code. The other code is called RNA.</p>
<p>RNA code is interesting in that it can be edited. One kind of editing, called splicing, removes a piece from the middle of the code, and stitches the two ends together. The marvel of splicing is that it can be used to produce two different kinds of instructions from the same piece of RNA code. RNA made from the <em>Pax6</em> can be spliced in just such a manner. As a consequence, two different kinds of instructions can be generated from the same <em>Pax6</em> RNA.</p>
<p>In the <a href="http://www.nature.com/srep/2014/140305/srep04256/full/srep04256.html?WT.ec_id=SREP-20140311">new study</a>, Atsushi Ogura at the Nagahama Institute of Bio-Science and Technology and colleagues found that <em>Pax6</em> RNA splicing has been used to create a camera eye in a surprising lineage. It occurs in the lineage that includes squid, cuttlefish, and octopus – the cephalopods. </p>
<p>Cephalopods have a camera eye with the same features as the vertebrate camera eye. Importantly, the cephalopod camera eye arose completely independently from ours. The last common ancestor of cephalopods and vertebrates existed more than 500m years ago. </p>
<p><em>Pax6</em> RNA splicing in cepahlopods is a wonderful demonstration of how evolution fashions equivalent solutions via entirely different routes. Using analogous structures, evolution can provide remarkable innovations. </p><img src="https://counter.theconversation.com/content/26265/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Malcolm Campbell receives funding from the Natural Sciences and Engineering Research Council of Canada, and from Genome Canada.</span></em></p>Eyes and wings are among the most stunning innovations evolution has created. Remarkably these features have evolved multiple times in different lineages of animals. For instance, the avian ancestors of…Malcolm Campbell, Professor & Vice-Principal Research, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/150792013-06-13T03:44:07Z2013-06-13T03:44:07ZSquid or swallow: the sexual tastes of a cephalopod<figure><img src="https://images.theconversation.com/files/25456/original/tjyqtmsn-1371088012.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sexual activity of the southern bottletail squid involves choosy females eating losers' ejaculate.</span> <span class="attribution"><span class="source">Saspotato</span></span></figcaption></figure><p>In romantic circles, reproduction is viewed as a harmonious venture between the sexes. After all, if you aim to produce the best offspring possible, wouldn’t it also be best to cooperate with your partner?</p>
<p>In recent decades, however, evolutionary biologists have revealed this harmonious ideal could not be <a href="http://en.wikipedia.org/wiki/Sexual_conflict">further from the truth</a>. And, contrary to what you may think, males don’t always have the upper hand when it comes to sexual conflict.</p>
<p>In a paper <a href="http://rsbl.royalsocietypublishing.org/content/9/4/20130192">published in Biology Letters</a> last week, my colleagues and I showed female southern bottletail squid dictate which lucky male’s sperm they use to fertilise their eggs - and which unlucky sperm they eat instead.</p>
<h2>Can’t we all just get along?</h2>
<p>What is now clear is that fierce battles between the sexes are being fought almost everywhere you look in sexually-reproducing species.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/25455/original/dqpgpybb-1371087846.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"></span>
<span class="attribution"><span class="source">JD Hancock</span></span>
</figcaption>
</figure>
<p>The reasons underlying this “sexual conflict” are due to the different ways in which males and females maximise their reproductive success. </p>
<p>For males, reproduction is typically only limited by the number of mates he can find. Sperm is cheap to produce and they are plentiful, so males are expected to try to mate with as many females as possible.</p>
<p>For females, it’s more a case of quality rather than quantity. Compared to sperm, eggs are much more expensive to produce and there are fewer of them available to be fertilised so females are expected to maximise their reproductive success by mating with high quality suitors.</p>
<p>These differences in ideal mating strategies and reproductive costs are the key to sexual conflict.</p>
<p>With a mismatch as to what is an “optimal reproductive effort”, both males and females attempt to pay the lowest price for reproduction, while still getting the biggest “bang for their buck”.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/25460/original/gvpyhhvn-1371090401.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ouch - a seed beetle’s penis.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>Several studies have shown how such sexual conflict has resulted in some quite bizarre, and at times brutal, reproductive strategies.</p>
<p>Seed beetles, for example, have evolved almost <a href="http://www.wired.co.uk/news/archive/2012-10/26/beetle-penis-spikes">barbaric looking penises</a>, aimed specifically at damaging the internal reproductive tract of the female. Some male flies have even <a href="http://www.sciencedirect.com/science/article/pii/S0965174896000847?np=y">evolved ejaculates</a> that not only stimulate the female to lay eggs, but also decrease her life span.</p>
<p>In such instances, males have evolved reproductive strategies aimed specifically at harming the female. By making the act of copulation even more costly for females, males lessen the likelihood of her mating again, thereby increasing his own chances of fertilising her eggs.</p>
<p>But are the scales of sexual conflict always tipped so heavily in the male’s favour?</p>
<h2>Ejaculate on the menu</h2>
<p>In the southern bottletail squid (<em><a href="http://australianmuseum.net.au/Southern-Bottletail-Squid-Sepiadarium-austrinum-Berry-1921">Sepiadarium austrinum</a></em>) females appear to engage in some reproductive manipulation of their own.</p>
<p>During copulation, males pass numerous sperm packages (<a href="http://en.wikipedia.org/wiki/Spermatophore">spermatophores</a>) to the female. These evert to form small, balloon-like structures (<a href="http://www.merriam-webster.com/dictionary/spermatangium">spermatangia</a>) that glue to the membrane around her mouth on an area known as the buccal cavity. Here, they are stored until she is ready to fertilise her eggs.</p>
<p>Importantly, the male’s sperm do not enter the reproductive tract, instead remaining housed inside their balloon-like casings. Although these spermatangia do offer some protection, the external nature of the buccal cavity means females are only able to store them for about three weeks before they, and the numerous sperm within, are lost.</p>
<p>When she is ready to produce a clutch, she extracts an egg from her body with her arms, passes it across the stored sperm bulbs, and then places it on seaweed or in crevices on the sea floor. </p>
<p>But recently it has been found these females will also eat the male’s spermatangia after copulation. Furthermore, she uses the nutrients from this behaviour for both tissue growth and the development of her unfertilised eggs. You can see this behaviour in the video below.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/eFdt0aKuKGk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>As sperm storage is only short-term, if females do not lay eggs soon after mating, males could completely miss out on fertilising her eggs, and instead act as a contributor for the next male that comes along.</p>
<p>But are males entirely at the mercy of the females’ culinary whims?</p>
<h2>Not all squid are equal</h2>
<p>It appears that this exposure to ejaculate consumption has driven males to develop some counter-strategies of their own.</p>
<p>When assessing a female as a potential partner, males show a clear preference for larger females, often refusing to mate with sexually mature females that are too small. When we examined this closer, we actually found smaller females are the ones that will eat the most of the male’s ejaculate.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/25457/original/h9wqq5rm-1371089404.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"></span>
<span class="attribution"><span class="source">Ben Clifford</span></span>
</figcaption>
</figure>
<p>So males appear to be using female size as a way to minimise their exposure to ejaculate consumption.</p>
<p>By looking closely at this inconspicuous squid, we have uncovered a range of questions about cephalopod reproductive strategies. </p>
<p>Do females view males as a possible food source? Are they even assessing the quality of their mate, saving the sperm of the best males for egg fertilisation whilst eating the rest? Is it possible that males have even evolved manipulative strategies of their own to ensure their sperm is used in offspring production?</p>
<p>Regardless of what is around the corner, this research highlights how the evolutionary implications of a single adaptation can dramatically affect the life history of a species. </p>
<p>Such studies not only give us insight into the mysterious world of cephalopods, but also provide an understanding as to how the costs of reproduction have worked to shape the evolution of all sexually-reproducing species.</p><img src="https://counter.theconversation.com/content/15079/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ben Wegener received funding from Monash University, the Victorian Marine Science Consortium, the Linnean Society of New South Wales, the Ecological Society of Australia and the Holsworth Wildlife Research Endowment.</span></em></p>In romantic circles, reproduction is viewed as a harmonious venture between the sexes. After all, if you aim to produce the best offspring possible, wouldn’t it also be best to cooperate with your partner…Ben Wegener, PhD candidate, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.