tag:theconversation.com,2011:/au/topics/blue-whales-4277/articlesblue whales – The Conversation2022-08-18T04:36:42Ztag:theconversation.com,2011:article/1885222022-08-18T04:36:42Z2022-08-18T04:36:42ZWarming oceans may force New Zealand’s sperm and blue whales to shift to cooler southern waters<figure><img src="https://images.theconversation.com/files/479763/original/file-20220817-20107-otygi7.jpg?ixlib=rb-1.1.0&rect=17%2C23%2C1687%2C722&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>The world’s oceans are absorbing more than <a href="https://www.un.org/en/climatechange/science/climate-issues/ocean-impacts">90% of the excess heat and energy</a> generated by rising greenhouse gas emissions. </p>
<p>But, as the oceans keep warming, rising sea temperatures generate unprecedented cascading effects that include the melting of polar ice, rising seas, marine heatwaves and ocean acidification.</p>
<p>This in turn has profound impacts on marine biodiversity and the lives and livelihoods of coastal communities, especially in island nations such as New Zealand. </p>
<p>In our latest <a href="https://www.sciencedirect.com/science/article/pii/S1470160X22007075?via%3Dihub">research</a>, we focused on great whales – sperm and blue whales in particular. They are crucial for maintaining healthy marine ecosystems, but have limited options to respond to climate change: either adapt, die, or move to stay within optimal habitats. </p>
<p>We used mathematical models to predict how they are likely to respond to warming seas by the end of the century. Our results show a clear southward shift for both species, mostly driven by rising temperatures at the sea surface. </p>
<figure class="align-center ">
<img alt="Sperm whales (left) and blue whales (right)" src="https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=184&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=184&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=184&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=231&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=231&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479117/original/file-20220815-17-lz4b8o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=231&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sperm whales (left) and blue whales (right) are both affected by rising ocean temperatures.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Computing the fate of whales</h2>
<p>Data on the local abundance of both whales species are <a href="https://www.int-res.com/abstracts/meps/v690/p201-217/">deficient</a>, but modelling provides a powerful tool to predict how their range is likely to shift.</p>
<p>We used a <a href="http://macroecointern.dk/pdf-reprints/AraujoNew2007.pdf">combination of mathematical models</a> (known as correlative species distribution models) to predict the future range shifts of these whale species as a response to three future climate change scenarios of differing severity, as outlined by the Intergovernmental Panel on Climate Change (<a href="https://www.ipcc.ch">IPCC</a>). </p>
<figure class="align-center ">
<img alt="Aerial view of a blue whale" src="https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&rect=5%2C95%2C1708%2C786&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479230/original/file-20220815-13-pirita.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Blue whales forage off the coast of New Zealand.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We applied these models, using the whales’ present distributions, to build a set of environmental “rules” that dictate where each species can live. Using climate-dependent data such as sea-surface temperature and chlorophyll A (a measure of phytoplankton growth), as well as static data such as water depth and distance to shore, we applied these rules to forecast future habitat suitability.</p>
<p>We chose a scenario of “<a href="https://www.nature.com/articles/d41586-020-00177-3">modest</a>” response to cutting greenhouse gas emissions (the IPCC’s mitigation strategy RCP4.5), which is the most likely given the current policies, and a worst-case scenario (no policy to cut emissions, RCP8.5), assuming the reality will likely be somewhere between the two.</p>
<figure class="align-center ">
<img alt="Projected change in habitat suitability by 2100, for sperm (left panels) and blue (right panels) whales under two IPCC climate scenarios: modest mitigation (RCP4.5) and no mitigation (RCP8.5). Percentages are expressed as relative to each species' present" src="https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=504&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=504&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=504&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=633&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=633&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479526/original/file-20220817-5564-sdyi9v.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=633&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Projected change in habitat suitability by 2100, for sperm (left panels) and blue (right panels) whales under two IPCC climate scenarios: modest mitigation (RCP4.5) and no mitigation (RCP8.5). Percentages are expressed as relative to each species’ present-day distribution.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our projections suggest current habitats in the ocean around the North Island may become unsuitable if sea-surface temperatures continue to rise. </p>
<p>These range shifts become even stronger with increasing severity of climate change. For sperm whales, which are currently abundant off Kaikōura where they support eco-tourism businesses, the predicted distribution changes are even more evident than for blue whales, depending on the climate change scenario.</p>
<p>While our results do not predict an overall reduction in suitable habitat that would lead to local extinctions, the latitudinal range shifts are nevertheless bound to have important ecological consequences for New Zealand’s marine ecosystems and the people who depend on them. </p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/sea-creatures-store-carbon-in-the-ocean-could-protecting-them-help-slow-climate-change-108872">Sea creatures store carbon in the ocean – could protecting them help slow climate change?</a>
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</em>
</p>
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<h2>How whales maintain ecosystems</h2>
<p>Great whales are marine ecosystem engineers. They modify their habitats (or create new ones), to suit their needs. In fact, these activities create conditions that other species rely on to survive.</p>
<p>They engineer their environment on several fronts. By feeding in one place and releasing their faeces in another, whales convey minerals and other nutrients such as nitrogen and iron from the deep water to the surface, as well as across regions. This process, known as a “<a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013255">whale pump</a>”, makes these nutrients available for phytoplankton and other organisms to grow. </p>
<p>This is very important because phytoplankton contributes about <a href="https://education.nationalgeographic.org/resource/plankton-revealed">half of all oxygen to the atmosphere</a> and also captures <a href="https://www.imf.org/Publications/fandd/issues/2019/12/natures-solution-to-climate-change-chami">about 40% of all released carbon dioxide</a>. By helping the growth of phytoplankton, whales indirectly contribute to the <a href="https://theconversation.com/tiny-plankton-drive-processes-in-the-ocean-that-capture-twice-as-much-carbon-as-scientists-thought-136599">natural ocean carbon sink</a>. </p>
<p>On top of this, each great whale accumulates about <a href="https://www.arcticwwf.org/the-circle/stories/protecting-the-earth-by-protecting-whales/">33 tonnes of carbon dioxide in their body</a>, which they take to the ocean floor when they die and their carcass sinks.</p>
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<strong>
Read more:
<a href="https://theconversation.com/bottoms-up-how-whale-poop-helps-feed-the-ocean-27913">Bottoms up: how whale poop helps feed the ocean</a>
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</em>
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<hr>
<p>Ultimately, the impact of warming oceans on whale distribution is an additional stress factor on ecosystems already under pressure from wider threats, including acidification, pollution and over-exploitation. </p>
<figure class="align-center ">
<img alt="An aerial view of a blue whale" src="https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479276/original/file-20220816-22-uw489z.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Blue whales convey nutrients between different parts of the ocean during their migration.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A way forward to help whales</h2>
<p>Sperm whales are the largest toothed whales (odontocetes) and deep-diving apex predators. They primarily feed on squid and fish that live near the bottom of the sea.</p>
<p>Blue whales are baleen whales (mysticetes) and filter small organisms from the water. They feed at the surface on zooplankton, particularly dense krill schools along coastlines where cold water from the deep ocean rises toward the surface (so-called <a href="https://oceanservice.noaa.gov/facts/upwelling.html">upwelling areas</a>). </p>
<p>These differences in feeding habits lead to divergent responses to ocean warming. Blue whales show a more distinct southerly shift than sperm whales, particularly in the worst-case scenario, likely because they feed at the surface where ocean warming will be more exacerbated than in the deep sea. </p>
<figure class="align-center ">
<img alt="A fluke of a diving sperm whale." src="https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479273/original/file-20220816-22-3peekd.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">
<figcaption>
<span class="caption">A population of sperm whales is currently resident off the coast of Kaikōura.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Both species have important foraging grounds off New Zealand which may be compromised in the future. Sperm whales are currently occurring regularly off Kaikōura, while blue whales forage in the South Taranaki Bight. </p>
<p>Despite these ecological differences, our results show that some future suitable areas around the South Island and offshore islands are common to both species. These regions could be considered sanctuaries for both species to retreat to or expand their habitat in a warming world. This should warrant <a href="https://environment.govt.nz/assets/Publications/Files/Environmental-Report-Card-Marine-Areas-with-Legal-protection_0.pdf">increased protection of these areas</a>.</p><img src="https://counter.theconversation.com/content/188522/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frédérik Saltré receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Karen Stockin is a Professor of Marine Ecology at Massey University (New Zealand) and a Rutherford Discovery Fellow (Royal Society Te Aparangi). Karen is further professionally affiliated with the International Whaling Commission (United Kingdom) and the Society for Marine Mammalogy (USA)</span></em></p><p class="fine-print"><em><span>Katharina J. Peters is a postdoctoral researcher at the University of Canterbury (New Zealand). She is also professionally affiliated with Massey University (New Zealand), the University of Zurich (Switzerland), and Flinders University (Australia). </span></em></p>Sperm whales support ecotourism in Kaikōura and blue whales come to feed off the New Zealand coast – but both may become a rare sight as ocean temperatures continue to rise.Frédérik Saltré, Research Fellow in Ecology for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityKaren A Stockin, Professor - Marine Ecology / Rutherford Discovery Fellow, Massey UniversityKatharina J. Peters, Postdoctoral Fellow, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1596362021-05-03T20:07:24Z2021-05-03T20:07:24ZCurious kids: do whales fart and sneeze?<figure><img src="https://images.theconversation.com/files/398272/original/file-20210503-17-10vkbfa.png?ixlib=rb-1.1.0&rect=664%2C0%2C3329%2C2000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Wes Mountain/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><blockquote>
<p>Do whales fart and sneeze? — Guy, age 8, Sydney</p>
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<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>I’ve waited a long time for a question like this! I usually talk about whale snot for my research (yes, whales have snot), and I’m so excited to look into this, too.</p>
<h2>Let’s start with the tail end first: farts</h2>
<p>Yes, whales do fart. Can you imagine the size and bubbles of a fart from the world’s biggest animal, the blue whale? </p>
<p>I’m yet to experience this, but I know of some lucky scientists who have seen a humpback whale fart. They tell me it looks like bubbles coming out underneath its body near the tail. That’s where the whale bum is — the smellier blowhole. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/5mEePulli3c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Most likely a humpback whale fart. Sound effect added.</span></figcaption>
</figure>
<p>Whales are <a href="https://australian.museum/learn/species-identification/ask-an-expert/what-is-a-mammal/">mammals</a>, just like us. This means they breathe air, give birth to live young, provide their young with milk and have hair, usually in the form of whiskers around their mouth. They also have digestive processes to help break down their food. </p>
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Read more:
<a href="https://theconversation.com/curious-kids-what-sea-creature-can-attack-and-win-over-a-blue-whale-98551">Curious Kids: What sea creature can attack and win over a blue whale?</a>
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<p>Unlike us, whales don’t chew their food but swallow it whole. <a href="https://www.smithsonianmag.com/science-nature/history-toothless-whales-180964717/">Baleen</a> or toothless whales, for example, use long hair-like structures to feed on krill and fish. Their food is later broken down across four stomach chambers. </p>
<p>As their bodies break this food down (via stomach acid), it produces gases, which are released as farts and eventually poo. </p>
<p>In fact, whale poo is one of the coolest looking in the animal kingdom. Blue whale poo can be bright orange! </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CN8x-_FDyBb/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Back to the top end: do whales sneeze?</h2>
<p>The short answer, no. </p>
<p>Unlike us, whales need to think about breathing. When they want to take a breath, they need to swim to the surface. If they don’t, they could drown. </p>
<p>This means whales also <a href="https://www.scientificamerican.com/article/how-do-whales-and-dolphin/">sleep</a> differently to us. They can rest different parts of their brain at a time, and take naps before rising to the surface to breathe. </p>
<p>And unlike us, they can’t breathe through their mouth and instead use their blowhole or nose to breath. This is like having an inbuilt snorkel on top of their head. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-do-sharks-sneeze-77399">Curious Kids: Do sharks sneeze?</a>
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</em>
</p>
<hr>
<p>This makes it much easier for them to swim, breathe and eat — all at the same time. And they don’t have to worry about food going down the wrong way as their air and lung passages are separated. </p>
<p>We sneeze automatically and involuntarily if something tickles our nose. If whales get something caught in their noses, they could clear it using a big exhale through their blowhole, like blowing their nose. This would serve a similar function to our sneezing.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.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 humpback whale takes a breath in Antarctica.</span>
<span class="attribution"><span class="source">Dr Vanessa Pirotta</span></span>
</figcaption>
</figure>
<h2>BUT, if a whale were to sneeze…</h2>
<p>It would be big! For comparison, an adult human’s lungs can hold around six litres of air. But a humpback whale can hold over 1,000 litres — that’s a lot of bubbles! </p>
<p>You can actually see a whale’s breath: it’s a mixture of lung bacteria, hormones, proteins and lipids. It’s officially called “whale lung microbiota” — or whale snot — and looks like water droplets. </p>
<p>As a scientist, I use <a href="https://www.frontiersin.org/articles/10.3389/fmars.2017.00425/full">drones</a> to sample whale snot to learn more about whale health. </p>
<p>We found the whales off Sydney didn’t even know their snot was being collected through this method. This is much safer for the whales and us as researchers as we don’t need to get close to each other. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/edS1uhO4LUw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Humpback whale snot collection via research drone off Sydney.</span></figcaption>
</figure>
<p>Well there you have it, we’ve covered both ends of a whale. They’re incredible creatures who do enormous farts — thanks for the question! </p>
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<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>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/159636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa Pirotta 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>Human farts and sneezes can be big — so imagine the size if they came from the world’s biggest animals?Vanessa Pirotta, Wildlife scientist, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1356842020-05-12T19:45:54Z2020-05-12T19:45:54ZI measure whales with drones to find out if they’re fat enough to breed<figure><img src="https://images.theconversation.com/files/331234/original/file-20200429-110734-1uajmop.jpg?ixlib=rb-1.1.0&rect=15%2C7%2C5027%2C3349&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>We set off from Fremantle Harbour at 6 am – a ridiculous hour university students aren’t usually accustomed to – and sailed to Perth Canyon, 120 kilometres away.</p>
<p>A fellow volunteer and I were constantly on watch, too nervous and excited to take our eyes off the horizon in case we missed the tell-tale spray of a pygmy blue whale blow. </p>
<p>We searched for hours with nothing to show for our efforts. My eyes began playing tricks on me. Was that white dot in the far distance the blow of a blue whale? Was the crest of that wave more than just white water?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331245/original/file-20200429-110765-4hn4rj.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">Whales can be hard to spot because some species spend little time at the surface.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>In the early afternoon, finally, a magnificent spray of white water. Fully visible at 9 metres above the ocean surface, the sign of a pygmy blue whale. We surveyed about six blues that day, as well as a pod of bottlenose dolphins. </p>
<p>The behaviour of whales and dolphins means some species, including blue whales, spend little time at the surface. So despite their overwhelming size, they can be hard to find and tough to study.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-team-uses-crossbows-and-drones-to-collect-bacteria-from-whales-and-the-results-are-teaching-us-how-to-keep-whales-healthy-128529">My team uses crossbows and drones to collect bacteria from whales – and the results are teaching us how to keep whales healthy</a>
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</em>
</p>
<hr>
<p>That’s one reason we need to rely on drones. <a href="https://www.scu.edu.au/engage/news/latest-news/2020/when-a-tape-measure-wont-do.php">My research</a> will use drones to collect video footage of humpback and pygmy blue whales in Australian waters. From this footage, we can extract still images to take measurements along the length and width of the whale. </p>
<p>These measurements will let us calculate the size and volume of a whale, and using this we can determine an individual’s body condition – an indication of its health.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334218/original/file-20200512-66707-1jqoc6i.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">I use drones to find whales, then video them lying flat on the surface.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Using drones for marine science</h2>
<p>Advancements in drone technology have allowed them to be used in a variety of research projects, particularly in marine science, such as marine fauna abundance estimates, habitat use and behavioural studies. This is because drones are relatively cheap, accessible and easy to use. </p>
<p>Drones became a widely used marine scientific tool in 2015, and became more popular in 2018. Before then, researchers used manned aircraft to assess body condition from birds-eye view images of whales. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/cbxSBDopVyw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Drones captured this breathtaking footage.</span></figcaption>
</figure>
<p>But manned aircraft can be expensive – think plane hire cost, fuel, pilot hire and airport fees – and pose extra risks to researchers on board. </p>
<p>The drones I’ll be using will be around 20 m above the water, capturing video footage of the whale for ten minutes. </p>
<p>But this can be tricky – whales are great swimmers and can move in all different directions, arching their back, rolling over or even twisting to one side. We need the whale lying flat near the surface of the water to measure it.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=487&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=487&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=487&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=612&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=612&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331250/original/file-20200429-110738-1opxvxa.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=612&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">a) an example of an aerial photograph of a humpback whale using an unmanned aerial vehicle and b) the position of measurements taken to assess body condition (the diagram shows width taken at 10% increments for clarity only).</span>
<span class="attribution"><a class="source" href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.1468">[From Christiansen et al (2016)](https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.1468)</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Using a statistical software program, the focal length of the camera and the altitude of the drone, I can turn measurements of its total length from pixels to absolute metres. </p>
<p>From there, I can calculate its volume to determine whether it’s in good nick, comparing it to other whales from its population.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australian-sea-lions-are-declining-using-drones-to-check-their-health-can-help-us-understand-why-127523">Australian sea lions are declining. Using drones to check their health can help us understand why</a>
</strong>
</em>
</p>
<hr>
<h2>Sizing up whales</h2>
<p><a href="https://australianmuseum.net.au/learn/animals/mammals/humpback-whale/">Humpback whales</a> can weigh up to 40,000 kg and grow to about 13 to 18 m, with females usually the larger of the two. <a href="https://www.nationalgeographic.com/animals/mammals/b/blue-whale/">The blue whale</a>, the largest animal on Earth, can reach 24 to 30 m in length, weighing in at a whopping 190,000 kg. </p>
<p>My research links the condition of a whale’s body to the timing of its migration. Understanding this relationship is important because it’ll hopefully increase our understanding about what trade-offs whales make during their migration.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-whales-big-but-not-bigger-128222">Why are whales big, but not bigger?</a>
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</em>
</p>
<hr>
<p>For example, humpback whales rely on stored energy during their annual migration from their feeding grounds in Antarctica to their breeding grounds in the north west (Camden Sound) and eastern (Great Barrier Reef) waters of Australia. This means they don’t eat during this time. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331241/original/file-20200429-110738-15pgovr.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">The blue whale is the largest animal known to exist on Earth.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>So, their body condition will determine how long they can physically spend in these breeding grounds. In other words, the more energy stores they have, the more time they can go without feeding. </p>
<p>While on the breeding grounds, whales also compete for breeding opportunities and calving. The most <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.1468">energetically demanding</a> of these is calving, as the energy a mother passes onto her calf <a href="https://www.int-res.com/abstracts/meps/v592/p267-281">will influence</a> her calf’s growth rate and survival.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331246/original/file-20200429-110742-zkcfb3.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">Calving demands the most energy from whales.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Climate change threatens food supply</h2>
<p>Humpback whale numbers have been bouncing back since <a href="https://www.environment.gov.au/marine/marine-species/cetaceans/whaling">commercial whaling for humpbacks</a> in Australia stopped in 1963. </p>
<p>More globally, many whale populations, <a href="https://www.fisheries.noaa.gov/species/blue-whale">including blue whales</a>, are <a href="https://www.environment.gov.au/marine/marine-species/cetaceans/whaling">slowly recovering</a> since the International Whaling Commission moratorium on commercial whaling started in 1986. But climate change adds new, and possibly unknown, threats to whales. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-iceland-is-set-to-resume-whaling-despite-international-opposition-95642">Why Iceland is set to resume whaling despite international opposition</a>
</strong>
</em>
</p>
<hr>
<p>In particular, climate change – including changes in sea temperatures, ocean acidification, reduction in sea ice, primary productivity and changes to ocean currents – <a href="https://blog.csiro.au/climate-link-found-between-krill-and-whales/">can threaten</a> the main prey of whales: krill. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331247/original/file-20200429-110785-dr68gx.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">Human activity in the ocean and climate change can threaten whales.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Whales must consume large amounts of food per day to survive. And whales with reduced fat reserves <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.1468">have less chance</a> of reproducing successfully. If their main food source is no longer there, they may not get enough food to make these long migrations, or to give enough energy to their calves for survival and growth.</p>
<p>Females may skip a reproductive cycle to ensure they have enough energy reserves for future pregnancy. Males may also spend less time on the breeding grounds if they don’t have sufficient energy reserves, decreasing their breeding opportunities.</p>
<p><a href="https://www.nature.com/articles/nature02996">Declining krill stock in the Southern Ocean</a> plays a big role, but so do other stressors in their environment from shipping, oil and gas production, and other increased human activities in the ocean. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-to-understand-the-culture-of-whales-so-we-can-save-them-123884">We need to understand the culture of whales so we can save them</a>
</strong>
</em>
</p>
<hr>
<p>So until we better understand these mysterious and enigmatic creatures, I’ll forgive the early morning starts. I’ll embrace the wind in my face and the salt in my hair, knowing the welfare of whales around the world is everyone’s responsibility.</p><img src="https://counter.theconversation.com/content/135684/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Grace Russell receives funding from the Australian Government RTP (Research Training Program) Scholarship and the Holsworth Wildlife Research Endowment. </span></em></p><p class="fine-print"><em><span>Daniele Cagnazzi 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>Some species, including blue whales, spend little time at the surface. So despite their overwhelming size, they can be hard to find and tough to study.Grace Russell, PhD Candidate, Southern Cross UniversityDaniele Cagnazzi, Researcher, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1282222019-12-12T19:03:00Z2019-12-12T19:03:00ZWhy are whales big, but not bigger?<figure><img src="https://images.theconversation.com/files/306633/original/file-20191212-85417-hq31z6.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C5176%2C3437&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Minke whale.</span> <span class="attribution"><span class="source">Jeremy Goldbogen</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Both toothed and baleen (filter-feeding) whales are among the largest animals ever to exist. Blue whales, which measure up to 100 feet (30 meters) long and can weigh over 150 tons, are the largest animals in the history of life on Earth. </p>
<p>Although whales have existed on this planet for some 50 million years, they only evolved to be truly gigantic in <a href="https://doi.org/10.1098/rspb.2017.0546">the past five million years or so</a>. Researchers have little idea <a href="https://doi.org/10.1073/pnas.1804077115">what limits their enormous size</a>. What is the pace of life at this scale, and what are the consequences of being so big?</p>
<p>As scientists who study <a href="https://scholar.google.com/citations?user=uo1sSBwAAAAJ&hl=en">ecology</a>, <a href="https://scholar.google.com/citations?user=CBjDcy8AAAAJ&hl=en">physiology</a> and <a href="https://scholar.google.com/citations?user=TPY3-ccAAAAJ&hl=en">evolution</a>, we are interested in this question because we want to know the limits to life on Earth, and what allows these animals to live at such extremes. In a <a href="https://science.sciencemag.org/content/366/6471/1367">newly published study</a>, we show that whale size is limited by the largest whales’ very efficient feeding strategies, which enable them to take in a lot of calories compared to the energy they burn while foraging.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.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">A humpback whale approaches scientists in the Antarctic.</span>
<span class="attribution"><span class="source">Goldbogen Laboratory, Stanford University / Duke University Marine Robotics and Remote Sensing, taken under permit ACA / NMFS #14809</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Ways to be a whale</h2>
<p>The first whales on Earth had four limbs, <a href="https://ocean.si.edu/through-time/ancient-seas/evolution-whales-animation">looked something like large dogs</a> and lived at least part of their lives on land. It took about 10 million years for their descendants to evolve a completely aquatic lifestyle, and roughly 35 million years longer for whales to become the giants of the sea. </p>
<p>Once whales became completely aquatic some 40 million years ago, the types that succeeded in the ocean were either <a href="https://en.wikipedia.org/wiki/Baleen_whale">baleen whales</a>, which fed by straining seaweater through baleen filters in their mouths, or <a href="https://en.wikipedia.org/wiki/Toothed_whale">toothed whales</a> that hunted their prey using <a href="https://en.wikipedia.org/wiki/Animal_echolocation">echolocation</a>. </p>
<p>As whales evolved along these two paths, a process called <a href="https://en.wikipedia.org/wiki/Upwelling">oceanic upwelling</a> was intensifying in the waters around them. Upwelling occurs when strong winds running parallel to the coast push surface waters away from the shore, drawing up cold, nutrient-rich waters from the deep ocean. This stimulates plankton blooms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=235&fit=crop&dpr=1 600w, https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=235&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=235&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=295&fit=crop&dpr=1 754w, https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=295&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/305967/original/file-20191209-90609-10zz2b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=295&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Upwelling occurs when winds displace surface waters, which are replaced by cold, nutrient-rich water that wells up from below.</span>
<span class="attribution"><a class="source" href="https://oceanservice.noaa.gov/facts/upwelling.html">NOAA</a></span>
</figcaption>
</figure>
<p>Stronger upwelling created the right conditions for baleen whale prey, such as <a href="https://en.wikipedia.org/wiki/Krill">krill</a> and <a href="https://en.wikipedia.org/wiki/Forage_fish">forage fish</a>, to become concentrated in dense patches along coastlines. Whales that fed on these prey resources could forage efficiently and predictably, allowing them to grow larger. <a href="https://doi.org/10.1098/rspb.2017.0546">Fossil records</a> showing that baleen whale lineages separately became gigantic all at the same time support this view. </p>
<h2>Really big gulps</h2>
<p>Is there a limit to how big whales can become? We tackled this question by drawing on animal energetics – the study of how efficiently organisms ingest prey and turn the energy it contains into body mass. </p>
<p>Getting large is based on simple math: If a creature can gain more calories than it spends, it gets bigger. This may seem intuitive, but demonstrating it with data collected from free-living whales was a gargantuan challenge. </p>
<p>To get the information, our international team of scientists attached high-resolution tags with suction cups to whales so that we could track their orientation and movement. The tags recorded hundreds of data points per second, then detached for recovery after about 10 hours. </p>
<p>Like a Fitbit that uses movement to record behavior, our tags measured how often whales fed below the ocean’s surface, how deep they dove and how long they remained at depth. We wanted to determine each species’ energetic efficiency – the total amount of energy that it gained from foraging, relative to the energy it expended in finding and consuming prey. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=335&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=335&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=335&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=422&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=422&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306466/original/file-20191211-95153-rnostz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=422&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tagged blue whale off the coast of Big Sur, California.</span>
<span class="attribution"><span class="source">Duke Marine Robotics & Remote Sensing under NMFS permit 16111</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Data in this study was provided by collaborators representing six countries. Their contributions represent tens of thousands of hours of fieldwork at sea collecting data on living whales from pole to pole.</p>
<p>In total, this meant tagging 300 toothed and baleen whales from 11 species, ranging from five-foot-long <a href="https://www.fisheries.noaa.gov/species/harbor-porpoise">harbor porpoises</a> to <a href="https://www.fisheries.noaa.gov/species/blue-whale">blue whales</a>, and recording more than 50,000 feeding events. Taken together, they showed that whale gigantism is driven by the animals’ ability to increase their net energy gain using specialized foraging mechanisms. </p>
<p>Our key finding was that <a href="https://en.wikipedia.org/wiki/Rorqual">lunge-feeding baleen whales</a>, which engulf swarms of krill or forage fish with enormous gulps, get the most bang for their buck. As these whales increase in size, they use more energy lunging – but their gulp size increases even more dramatically. This means that the larger baleen whales get, the greater their energetic efficiency becomes. We suspect the upper limit on baleen whales’ size is probably set by the extent, density and seasonal persistence of their prey.</p>
<p>Large toothed whales, such as <a href="https://en.wikipedia.org/wiki/Sperm_whale">sperm whales</a>, feed on large prey occasionally including the fabled <a href="https://ocean.si.edu/ocean-life/invertebrates/giant-squid">giant squid</a>. But there are only so many giant squid in the ocean, and they are hard to find and capture. More frequently, large toothed whales feed on medium-sized squid, which are much more abundant in the deep ocean.</p>
<p>Because of a lack of large enough prey, we found that toothed whales’ energetic efficiency decreases with body size – the opposite of the pattern we documented for baleen whales. Therefore, we think the ecological limits imposed by a lack of giant squid prey prevented toothed whales from evolving body sizes greater than sperm whales. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=486&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=486&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=486&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=611&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scaling of energetic efficiency in toothed whales and baleen whales.</span>
<span class="attribution"><a class="source" href="http://www.alexboersma.com">Alex Boersma</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>One piece of a larger puzzle</h2>
<p>This work builds on previous research about the <a href="https://doi.org/10.1098/rsbl.2016.0186">evolution of body size in whales</a>. Many questions remain. For example, since whales developed gigantism relatively recently in their evolutionary history, could they evolve to be even larger in the future? It’s possible, although there may be other physiological or biomechanical constraints that limit their fitness. </p>
<p>For example, <a href="https://doi.org/10.1073/pnas.1914273116">a recent study</a> that measured blue whale heart rates demonstrated that heart rates were near their maximum even during routine foraging behavior, thereby suggesting a physiological limit. However, this was the first measurement and much more study is needed.</p>
<p>We would also like to know whether these size limits apply to other big animals at sea, such as sharks and rays, and how baleen whales’ consumption of immense quantities of prey affect ocean ecosystems. Conversely, as human actions alter the oceans, could they affect whales’ food supplies? Our research is a sobering reminder that relationships in nature have evolved over millions of years – but could be disrupted far more quickly in the <a href="https://en.wikipedia.org/wiki/Anthropocene">Anthropocene</a>. </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><img src="https://counter.theconversation.com/content/128222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Savoca receives funding from the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Jeremy Goldbogen receives funding from the National Science Foundation and the Office of Naval Research. </span></em></p><p class="fine-print"><em><span>Nicholas Pyenson receives funding from the Smithsonian Institution.</span></em></p>How did whales that feed on tiny prey evolve into the largest creatures on Earth? And why don’t they get even bigger?Matthew Savoca, Postdoctoral researcher, Stanford UniversityJeremy Goldbogen, Assistant Professor of Biology, Stanford UniversityNicholas Pyenson, Research Geologist and Curator of Fossil Marine Mammals, Smithsonian InstitutionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1227892019-09-30T05:13:15Z2019-09-30T05:13:15ZCurious Kids: which is smarter – a blue whale or an orca?<figure><img src="https://images.theconversation.com/files/293527/original/file-20190923-23774-6uofxm.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C3493%2C2329&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blue whales and orcas are both specialists in their own way. You can't really measure which one is more intelligent. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/killer-whale-group-traveling-wild-90045763?src=UI9jSWprc_lTC_CwLvrksg-2-10">Shutterstock</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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au.</em> </p>
<hr>
<blockquote>
<p><strong>Which is smarter: blue whales or orcas? – Prasaad, age 6.</strong></p>
</blockquote>
<hr>
<p>There’s no simple answer. We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means.</p>
<p>It’s true that blue whales and orcas (also called killer whales) are both smart. They both have very large brains. Orcas have particularly large brains compared to their overall body size.</p>
<p>But it’s not just about brain size. When it comes to measuring intelligence, we might also consider things like:</p>
<ul>
<li>the number of nerve cells in the brain;</li>
<li>ability to navigate the deep, wide oceans;</li>
<li>solving difficult problems;</li>
<li>communicating;</li>
<li>working in teams.</li>
</ul>
<p>Let’s look at which animal is good at which skill.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-sea-creature-can-attack-and-win-over-a-blue-whale-98551">Curious Kids: What sea creature can attack and win over a blue whale?</a>
</strong>
</em>
</p>
<hr>
<h2>What can a blue whale do?</h2>
<p>There’s no doubt a blue whale is a very intelligent animal. </p>
<p>Blue whales eat krill, which are very tiny prawn-shaped animals that gather in huge swarms that are often far away from where blue whales give birth to their children. Despite the distance, blue whales are masters of finding krill. They are very good at navigating along coasts and across the deep, wide oceans.</p>
<p>In fact, blue whales are so smart they can work out if a swarm of krill is worth chasing. Blue whales are very good at finding krill that are fat and in big swarms so they do not waste their energy catching smaller swarms. Blue whales catch krill by rolling on their side and opening their mouths. It is a lot of work and they have to use a lot of energy to do it. </p>
<p>Blue whales also have excellent systems for <a href="https://www.nationalgeographic.com.au/science/blue-whales-and-communication.aspx">communicating</a> with each other. </p>
<h2>What can an orca do?</h2>
<p>Orcas are a kind of large dolphin and they have different strengths.</p>
<p>They are very good at working together. They form groups and hunt together for fish or other sea mammals – including whales. This is why they are called “killer whales”. </p>
<p>They are also expert communicators and have their own language – even certain noises that are <a href="https://www.nrcresearchpress.com/doi/abs/10.1139/z89-105#.XXXnL5MzaV4">used by a particular group</a> of orcas to show they are in the group.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Orcas form groups and hunt together.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pod-killer-whales-swimming-near-surface-723720937?src=WU9ZnnyzAkohfhv4dOT4BQ-1-20">Shutterstock</a></span>
</figcaption>
</figure>
<h2>They both are very intelligent in their own way</h2>
<p>Some scientists have wondered if you could measure intelligence by looking at how well animals teach their children how to behave – for example, how to find food, fight or stay safe. </p>
<p>Orcas are masters at teaching their children exactly what to do. This involves things like hunting in groups or sneaking up on a seal and grabbing it before sliding back into the water. </p>
<p>However, blue whales are also good at teaching their offspring skills such as long-distance navigation – in other words, finding their way around the vast oceans.</p>
<p>Both blue whales and killer whales have their own special behaviours and skills. We really can’t say which one is more intelligent because both are very intelligent in their own way.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-do-creatures-living-in-the-deep-sea-stay-alive-given-the-pressure-111940">Curious Kids: how do creatures living in the deep sea stay alive given the pressure?</a>
</strong>
</em>
</p>
<hr>
<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/122789/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Kerstin Bilgmann is an Honorary Research Fellow and Research Leader of the Marine Vertebrate Conservation and Evolution Laboratory in the Department of Biological Sciences, Macquarie University, Sydney. </span></em></p>We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means. Both have their own special behaviours and skills and we can’t say who is more intelligent.Kerstin Bilgmann, Lecturer in Biological Sciences, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/985512018-08-20T20:02:01Z2018-08-20T20:02:01ZCurious Kids: What sea creature can attack and win over a blue whale?<figure><img src="https://images.theconversation.com/files/232018/original/file-20180815-2915-163gn3u.jpg?ixlib=rb-1.1.0&rect=184%2C8%2C4962%2C3135&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blue whales are the largest creatures to have ever lived on Earth.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! You might also like the podcast <a href="http://www.abc.net.au/kidslisten/imagine-this/">Imagine This</a>, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.</em></p>
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<p><strong>What sea creature can attack and win over a blue whale? – Drake, age 7, Sydney.</strong></p>
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<p>Hi Drake. That is an interesting question.</p>
<p>As you probably know, blue whales are the largest creatures to have <a href="https://www.fisheries.noaa.gov/species/blue-whale">ever lived</a> on Earth – bigger than any dinosaur. They can grow up to 30 metres in length and weigh over 150 tonnes. This is very, very BIG. To give you an idea of how big a blue whale is, it’s the size of a Boeing 737 plane! Because of their size, power and speed, adult blue whales have virtually no natural ocean predators. </p>
<p>The only sea creature <a href="https://news.nationalgeographic.com/2017/05/killer-whale-attacks-blue-whale-monterey-drone-video/">known to attack blue whales</a> is the orca whale (scientific name: <em>Orcinus orca</em>) also known as the “killer whale”. They have been known to work in groups to attack blue whales. </p>
<p>However, there are very few reports of orcas actually killing blue whales. We know that orca whales interact with them because many blue whales carry scars from the teeth of orcas. But blue whales probably see orcas as more of a pest than a predator. </p>
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<a href="https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=547&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=547&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231985/original/file-20180814-2900-1vgdw0c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=547&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">Orcas have sharp teeth.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<img alt="" src="https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=114&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=114&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=114&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=143&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=143&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231008/original/file-20180808-191038-1i4p7vw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=143&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">Blue whales can grow 30 metres in length and weigh over 150 tonnes.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Blue_whale_size.svg">Kurzon/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>The human threat</h2>
<p>A much more serious problem for blue whales is humans. Humans have caused a lot of trouble for blue whales over the years.</p>
<p>One big problem is what we call “ship strikes”. This is when large ships collide with blue whales causing dreadful wounds and, in many cases, death.</p>
<p>Blue whales migrate freely across all the great oceans of the world to breed. They travel each year to the Antarctic in search of food. <a href="https://iwc.int/climate-change">Global warming</a> is a major future threat to their way of life. This is because rising sea temperatures and ocean acidification (which are caused by climate change) are likely to cause severe disruption to the production of their main food source, the very small crustacean we call “krill”.</p>
<p>Blue whales were the target of commercial whalers, mainly in Antarctica, between 1900 and the 1970s. During that time, <a href="https://www.biologicaldiversity.org/campaigns/esa_works/profile_pages/BlueWhale.html">over 330,000</a> blue whales were killed. </p>
<p>Fortunately - and only just in time - the <a href="https://iwc.int/status">International Whaling Commission</a> banned commercial whaling in 1966. Blue whales are now a <a href="https://www.fisheries.noaa.gov/species/blue-whale">protected species</a> and are recovering from the brink of extinction. People on whale watching trips at various locations around the world can see them, if they are lucky. The risk of whaling still exists in several countries, including Japan, Iceland and Norway. Many people in these countries are seeking to return to commercial whaling. Recently, whalers in Iceland <a href="http://www.abc.net.au/news/science/2018-07-20/dna-shows-blue-whale-hybrid-iceland-institute-says/10017276">killed a hybrid blue whale</a>. </p>
<h2>Blue whales can talk</h2>
<p>One of the most interesting things about blue whales is that they use very low frequency sounds to communicate. Through this they can talk to each other over great distances. The low frequency sounds can pass through the earth, so it’s possible to record their songs and sounds from anywhere in the world. </p>
<p>In the 1960s, an American scientist called <a href="http://www.cornell.edu/video/Christopher-Clark-Whale-Voices-from-the-Blue-Deep">Chris Clark</a> got permission to use the USA’s submarine listening system across the Atlantic Ocean to listen to blue whales. One day, he heard a blue whale calling from the far northeast Atlantic Ocean and realised another whale many thousands of miles away in the southwest Atlantic Ocean was answering it. Through their calls, he tracked them over the next few weeks moving towards each other. The two blue whales met and spent time together in the middle of the Atlantic. Then they separated and went on their way!</p>
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<a href="https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/232020/original/file-20180815-2912-1f9081k.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>
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<span class="caption">A pair of blue whales swims under the surface in Monterey Bay, California.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>It is important for all who are interested in the conservation and protection of these amazing creatures to remain vigilant and involved in making sure that they remain safe. Whales are part of the international heritage of all people of the Earth.</p>
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Read more:
<a href="https://theconversation.com/curious-kids-how-do-plastic-bags-harm-our-environment-and-sea-life-98859">Curious Kids: How do plastic bags harm our environment and sea life?</a>
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<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The only sea creature known to attack blue whales is the orca, also known as a ‘killer whale’. But humans present a much bigger threat to them.Wally Franklin, Researcher and co-director of the The Oceania Project, Southern Cross UniversityTrish Franklin, Researcher and co-director of The Oceania Project , Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/689682016-12-20T19:08:00Z2016-12-20T19:08:00ZEavesdropping reveals hidden marine mammal populations in the ocean<figure><img src="https://images.theconversation.com/files/146471/original/image-20161117-18138-1bcsiww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A blue whale surfaces</span> <span class="attribution"><span class="source">Joy Tripovich</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Acoustic monitoring of the calls of marine animals, such as whales and seals, could be the key to identifying new species, finding new population groups and mapping migration routes. </p>
<p>We recently used <a href="http://dx.doi.org/10.1093/jmammal/gyv065">custom-designed detection algorithms</a> to run through 57,000 hours of underwater ocean noise to find the songs of endangered blue whales, rather than listening for each whale call. This detection program saved us an enormous amount of processing time and will be critical in future acoustic monitoring research.</p>
<p>Some endangered marine animals, including several whale and seal species, are “cryptic species”: they’re genetically different but look alike. This means that they are often mistaken for one another when identified visually, making conservation plans difficult to implement.</p>
<p>However, most animals produce species-specific calls. Eavesdropping on their calls therefore provides a unique way to monitor them. This is completely rewriting our understanding of their population recovery. </p>
<h2>Recovery of the blue whale</h2>
<p>We recently discovered <a href="http://jmammal.oxfordjournals.org/content/jmammal/96/6/1184.full.pdf">two new blue whale populations</a> migrating off the east coast of Australia using this technology. This is important news as the blue whale has been slow to recover after being hunted to the brink of extinction. How can the largest animal that has ever lived, the Antarctic blue whale, swim undetected just off the coast of Sydney? </p>
<p>It is remarkable that we have only now discovered them there. It is possible that they only started using this route recently, or perhaps they have been there all along and we have missed them.</p>
<p>Fortunately for us, blue whales sing, allowing us to detect them using arrays of listening devices spanning sites across the Indian and Pacific oceans. However, the frequency of their song is so low that humans can’t hear it. </p>
<p>Blue whales produce different calls and these calls possibly reflect different subspecies. Their different songs help the International Whaling Commission manage the recovery of these subspecies. </p>
<h2>Blue whales speak with different dialects</h2>
<p>Globally, there are at least <a href="http://cetus.ucsd.edu/Publications/Publications/McDonaldJCRM2006.pdf">nine separate blue whale acoustic populations</a>, and Australia’s waters are home to at least three. </p>
<p>The west coast of Australia is a well-known blue whale feeding ground and both the Australian pygmy and Antarctic blue whales are common there. </p>
<p>Another popular blue whale feeding ground is in Southern Australia. Until recently the blue whales there were thought to be all <a href="http://www.int-res.com/articles/meps_oa/m421p243.pdf">pygmy blue whales</a>, but it was discovered that the Antarctic blue whale is also found there. </p>
<p>We were further surprised to find that the Antarctic blue whales <a href="http://jmammal.oxfordjournals.org/content/jmammal/96/3/603.full.pdf">remained all year off southern Australia</a>. In some years, they did not return to their krill-rich Antarctic feeding grounds in the summer, as we’d expect. </p>
<p>The east coast of Australia is not known as a blue whale site, so we were delighted to find two different acoustic populations in the Tasman Sea, all the way up to Samoa. We found the critically endangered Antarctic blue whale and, to the delight of our New Zealand colleagues, pygmy blue whales with a <a href="http://www.tandfonline.com/doi/pdf/10.1080/00288330.2006.9517442">New Zealand accent</a>. </p>
<p>Tasmania now looks like the boundary point separating the Kiwi and Aussie speaking pygmy blue whales. </p>
<h2>What about seals?</h2>
<p>Similar to whales, seals are also returning to our shoreline. Fur seals are an example of a marine cryptic species, and while some species are thriving, others are not.</p>
<p>The different fur seal species look similar. In fact, unless you are a seal expert, or a seal, it can be difficult to tell them apart. But we can easily recognise the different species because they have very different calls.</p>
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<p>The seals can recognise further subtle differences in calls between one another. To maintain their breeding territories the male seals fight and <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2008.00229.x/abstract">bark incessantly</a>. Each male has a <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2008.00229.x/abstract;jsessionid=22AF9AB796ACAFCBE08B76BFDD068E54.f01t03">distinctly different call</a>. </p>
<p>A male can recognise and respond differently to the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2008.00222.x/abstract">voices of his neighbours</a>, whose territory boundary lines have been established by weeks of confrontations, from <a href="http://www.sciencedirect.com/science/article/pii/S0376635708001368">the voices of unknown males</a> that are potentially a threat to his territory. </p>
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<a href="https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146481/original/image-20161117-19340-13ts0n4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&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">Fur seal mum and pup.</span>
<span class="attribution"><span class="source">Pixabay</span></span>
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<p>The female fur seals and their pups also have <a href="http://scitation.aip.org/content/asa/journal/jasa/120/1/10.1121/1.2202864">individually unique voices</a>. When a female returns from sea after days of hunting, she needs to find her pup from the hundreds of other pups on the island. The mum and pup call to find one another in the busy, noisy colony. The female recognises her <a href="http://www.tandfonline.com/doi/abs/10.1080/09524622.2009.9753605">pup’s unique call</a> and scent as part of the reunion. </p>
<p>Spying on animal songs gives new insights into undiscovered populations and new migratory routes, completely rewriting our understanding of these marine giants. Accurately evaluating the population status and trends of cryptic marine species is critical in developing conservation management strategies.</p><img src="https://counter.theconversation.com/content/68968/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joy Tripovich receives funding from the Winifred Violet Scott Trust and is affiliated with the E&ERC at UNSW Australia.</span></em></p><p class="fine-print"><em><span>Tracey Rogers receives funding from ARC. She is affiliated with the E&ERC at UNSW Australia</span></em></p>Songs of marine animals can help us discover new populations.Joy Tripovich, Postdoctoral Research Fellow in Marine Ecology, UNSW SydneyTracey Rogers, Associate Professor Evolution & Ecology, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/559412016-03-08T18:58:35Z2016-03-08T18:58:35ZAntarctica’s blue whales are split into three distinct populations<figure><img src="https://images.theconversation.com/files/114243/original/image-20160308-15328-1oky88f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">DNA analysis reveals that there are three populations of Antarctic blue whales.</span> <span class="attribution"><span class="source">Paula Olson, courtesy of IWC</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Antarctica’s critically endangered blue whales, the world’s largest animal, are made up of three populations, according to our new <a href="http://www.nature.com/articles/srep22291">DNA analysis</a>. </p>
<p>Although the groups occur together when feeding in Antarctic waters, they are genetically distinct. This suggests that the three groups breed in different locations – possibly even different oceans – when they head north in the winter.</p>
<p>If we can find out where they go, and what hazards they face on the way, we will be a step closer to helping them recover from their near-annihilation by whalers during the 20th century.</p>
<h2>Hidden giants</h2>
<p>It is a daunting task to understand the ecology of the Antarctic blue whale (<em>Balaenoptera musculus intermedia</em>). Even though they can weigh more than 160 tonnes – the heaviest ever known animal – and reach more than 30 metres in length, locating such a rare and highly mobile species in a vast and remote ocean can be like finding a needle in a haystack. And even having tracked them down, it can be hard to deduce anything about their population structure.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114237/original/image-20160308-15323-138k6aw.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 largest animal in the world.</span>
<span class="attribution"><span class="source">Paula Olson, courtesy of IWC</span></span>
</figcaption>
</figure>
<p>By comparing similarities and differences in the DNA of individuals, we can tell which individuals are part of the same population and estimate the number of populations. Individuals from the same breeding population are more genetically similar than those from different populations. But we need recently collected DNA samples to do this for current populations.</p>
<p>The standard way to get DNA from a blue whale is to take a biopsy by firing a dart that collects a small piece of skin and blubber, bounces off the whale and floats on the water for collection. It is akin to a pinprick for an animal as massive as a whale.</p>
<p>Long before we started working with blue whales in 2007, expeditions have been <a href="https://iwc.int/sower">carried out under the auspices of the International Whaling Commission</a> to research Antarctic whales. These expeditions involved collecting precious biopsy samples from blue whales and there is now a collection stretching back to 1990.</p>
<p>We were granted access to samples, totalling 142 whales, and used these to create the largest and therefore most powerful genetic data set so far created for Antarctic blue whales. As our research <a href="http://www.nature.com/articles/srep22291">published in Nature’s Scientific Reports</a> shows, we found that these whales fall into three genetically distinct groups.</p>
<h2>Where are these populations?</h2>
<p>Blue whales, like many other whales, migrate between their Antarctic summer feeding grounds and their winter breeding grounds at lower latitudes.</p>
<p>We know Antarctic blue whales feed in the Antarctic, which is where they were hunted during whaling in the 20th century and where the biopsy samples were collected.</p>
<p>We found that individuals from the three populations occur together throughout the Antarctic, although possibly in different proportions in different areas. This is probably because the blue whales need to rove long distances around Antarctica to find the massive amounts of krill that make up their sole food source.</p>
<p><iframe id="tc-infographic-236" class="tc-infographic" height="400" src="https://cdn.theconversation.com/infographics/236/bc14e5189a4da42a31724b8bc8aaf0f2ed2217a8/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p><strong>Distribution of samples from the three genetically distinct populations of Antarctic blue whales</strong></p>
<p>We suspect that the three populations go their separate ways when they head north to breed – presumably heading into the three major Southern Hemisphere ocean basins: the South Pacific, South Atlantic and Indian Oceans. </p>
<p>The next step will be to confirm this by finding their breeding grounds. This would involve satellite-tagging whales in Antarctic waters and then watching where they go. More biopsy samples could then be taken at the breeding grounds to confirm which populations are which.</p>
<h2>Knowledge for conservation</h2>
<p>Understanding the number of populations and their distribution is vital for helping Antarctica’s blue whales recover from 20th-century whaling, which reduced their numbers from <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2004.tb01190.x/abstract;jsessionid=9AD2973A594FC64045ED1627E769B019.d02t03">239,000 to just 360 individuals</a>. While they are now <a href="http://www.marinemammals.gov.au/sorp/antarctic-blue-whale-project">protected from whaling</a>, they remain <a href="http://www.iucnredlist.org/details/41713/0">critically endangered</a>.</p>
<p>Some populations may be more endangered than others and may face different human threats along their migration routes and at their breeding grounds. Failing to take conservation action at a population level could therefore lead to local extinctions at these locations.</p>
<p>One threat that differs in intensity between locations is noise pollution, such as from seismic surveys for oil and gas as well as shipping activity. These noises can be heard underwater hundreds of kilometres from their source. Whales communicate through sound, so noise pollution can hinder their communications or, in extreme cases, make areas uninhabitable.</p>
<p>Our latest findings, together with our previous work on <a href="http://www.abc.net.au/science/articles/2012/11/19/3635942.htm">hybridisation</a>, <a href="http://link.springer.com/article/10.1007%2Fs10592-010-0121-9">connectivity</a> and <a href="http://blogs.flinders.edu.au/flinders-news/2015/05/07/low-gene-diversity-in-blue-whales-is-natural-not-man-made/">population history</a> of blue whales, provides important pieces in the puzzle of this species. But we are still at the tip of the iceberg in our understanding of the world’s largest animal and in the pathway to their recovery from whaling.</p><img src="https://counter.theconversation.com/content/55941/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Catherine R. M. Attard has received funding from the Australian Marine Mammal Centre of the Department of the Environment.</span></em></p><p class="fine-print"><em><span>Luciana Möller has received funding from the Australian Marine Mammal Centre of the Department of the Environment.</span></em></p><p class="fine-print"><em><span>Luciano Beheregaray receives funding from the Australian Research Council.</span></em></p>Antarctica’s blue whales all feed in the same place. But a new genetic analysis suggests they are actually three separate populations that breed in different parts of the globe.Catherine R. M. Attard, Lecturer in Molecular Ecology, Flinders UniversityLuciana Möller, Associate Professor in Marine Biology, Flinders UniversityLuciano Beheregaray, Professor in Biodiversity Genetics and ARC Future Fellow, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/378152015-02-19T19:04:30Z2015-02-19T19:04:30ZSea creatures will get bigger and bigger (if we don’t eat them first)<p>When life on Earth began around 3.6 billion years ago, all organisms were small. Indeed, it took some 2.5 billion years to evolve any organism that grows larger than a single cell. </p>
<p>Since then, things have accelerated a bit and – along with the great diversification of body forms – animals have tended to get bigger. Indeed, the largest animal ever to live, the blue whale, is still very much with us, and has been swimming the world’s oceans for only a couple of million years – a mere blink of the eye in the long, long history of life in the sea.</p>
<p>This trend towards larger body sizes through evolutionary time has become known as Cope’s Rule, after the American palaeontologist Edward Drinker Cope. Cope’s rule has been documented or disputed in hundreds of studies of numerous animal lineages over the last century, but a new study in the journal <a href="http://www.sciencemag.org/lookup/doi/10.1126/science.1260065">Science</a> provides perhaps the most comprehensive test yet of its existence.</p>
<h2>Sea creatures are getting bigger</h2>
<p>The team, led by Noel Heim from Stanford University, delved into the fossil record to compile information on the body sizes of more than 17,000 kinds of marine animals that have existed since the start of the Cambrian period, 542 million years ago. The results are clear: both the average and maximum sizes of marine organisms have increased substantially over this period, whereas the minimum size has remained reasonably constant.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=977&fit=crop&dpr=1 600w, https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=977&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=977&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1227&fit=crop&dpr=1 754w, https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1227&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/72509/original/image-20150219-28215-ud6uqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1227&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fossil fan Edward Drinker Cope.</span>
</figcaption>
</figure>
<p>To some extent this may seem inevitable: if life starts small, the only way to go is bigger. And although evolutionary biologists are always wary of narratives of “progress”, many innovations in evolution require a large body size – for example, the smallest vertebrates are inevitably larger than the smallest invertebrates, because it takes a certain size of organism to pack in all the stuff that vertebrates have. </p>
<p>Likewise, warm-blooded marine animals like whales can only stave off hypothermia if they are more than about a metre long. So the re-invasion of the seas by the ancestors of today’s marine mammals imposed a new hard boundary on the minimum size within this group, which in turn affects the average size across groups.</p>
<p>In the new study, Heim and colleagues tested whether the observed increase in size could be explained by a simple evolutionary random walk, where body size is allowed to change randomly at each branching in the tree of life. They also modified this to impose a minimum possible size, such that the evolution of body sizes proceeded randomly but “bounced back” if a lineage hit this lower size limit. </p>
<p>Neither of these models fitted the observed data well. Instead, they show that only persistent directional selection for larger body sizes – due to the many advantages to being large – can explain the observed trends.</p>
<h2>Age of the giants</h2>
<p>Does this mean that sea creatures are all inexorably getting bigger, and will continue to do so until the oceans are full of behemoths? Not really. First, the minimum size has not changed, and – moving for a moment from evolution to ecology – it is well known that <a href="http://www.sciencemag.org/content/321/5887/399.abstract">most species are small</a>. In the seas this is especially pronounced, because marine food webs are typically highly size structured – that is, big things eat small things. It takes a lot of small fish to meet the energetic demands of a big fish, and so the only way these food webs can work is if small organisms substantially outnumber their larger predators.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/72505/original/image-20150219-28201-npc0gp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It’s a fish eat fish world.</span>
<span class="attribution"><span class="source">Pieter Bruegel the Elder, 1556</span></span>
</figcaption>
</figure>
<p>Second, Heim and colleagues show that most of the overall increase in body size across all marine animals is explained by the evolution of major new groups, with all of the anatomical and physiological innovation that implies. There is rather less of a drive towards larger sizes within any existing group. In fact, many ocean giants are already more or less as big as they could be, given physical and physiological limits. </p>
<p>In their fascinating study <a href="https://peerj.com/articles/715/">Sizing Ocean Giants</a> published in the journal PeerJ earlier this year, marine biologist Craig McClain and colleagues document the factors limiting size in many of the most conspicuous large marine species. These include the risk of tentacle tangling in jellyfish, metabolic constraints on giant clams, physiological limitations of pumping water over gills in large bony fish, or the reliance of blue whales on dense concentrations of their crustacean prey.</p>
<p>In the case of most groups of marine animals, then, it is unlikely that significantly larger members will evolve any time soon. So, even if Cope continues to rule unchallenged, a visitor to our future oceans is less likely to find them populated with fish the size of whales and whales the size of supertankers than with some new giants whose blueprints we do not yet know.</p>
<h2>The human factor</h2>
<p>However, Cope has an important rival now as an evolutionary force, and that is you, me, and everyone who directly or indirectly exploits our seas. The attitude of people down the ages when confronted with large marine creatures is encapsulated by my reaction when I first saw pictures of newly discovered <a href="http://www.bbc.co.uk/news/science-environment-16834913">giant deep sea amphipods</a>: “Barbecue!”. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/72508/original/image-20150219-28219-tefqnv.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">New species, new food?</span>
<span class="attribution"><span class="source">Oceanlab, University of Aberdeen</span></span>
</figcaption>
</figure>
<p>As a species we’ve been pretty effective at removing large animals wherever we roam. As McClain and colleagues say of manta rays (although this is equally applicable to most exploited marine creatures), “In the face of fishing pressure and other anthropogenic threats, it is likely that individuals in many populations may not be near their maximum possible ages or sizes.” In some species, <a href="http://www.sciencedirect.com/science/article/pii/S016953470700273X">such as plaice and cod</a>, fisheries appear to have driven selection for smaller body sizes, and our evolving understanding of <a href="https://theconversation.com/marine-species-are-more-threatened-than-we-thought-and-weve-only-looked-at-3-36914">extinction risk in the seas</a> suggests we should not take for granted the continued existence of the ocean’s giants.</p>
<p>Of course, we have been around for too short a time to know if human-driven selection will remain a true competitor to Cope’s rule in the longer term. Indeed, as this new research shows, previous mass extinctions have led to sharp increases in body size among survivors. So who knows? Maybe Cope will again rule the waves following the current human-driven extinction crisis.</p><img src="https://counter.theconversation.com/content/37815/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Webb 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>But the giants of the future won’t be the same fish, whales and sharks we know today.Tom Webb, Royal Society University Research Fellow, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/369272015-01-30T13:19:33Z2015-01-30T13:19:33ZIs a blue whale more authentic than Dippy? Not according to Moby Dick<figure><img src="https://images.theconversation.com/files/70613/original/image-20150130-25917-8yhnuh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">London's leviathan.</span> <span class="attribution"><span class="source">Natural History Museum</span></span></figcaption></figure><p>The Natural History Museum’s <a href="https://theconversation.com/evict-dippy-from-the-natural-history-museum-this-dinosaur-expert-says-go-for-it-36921">plan to remove “Dippy”</a>, the cast of a diplodocus skeleton, from its entrance hall, and replace it with a genuine skeleton of a blue whale has been met with outrage. The #savedippy campaign quickly started trending on Twitter.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"560735980760891392"}"></div></p>
<p>But Michael Dixon, the museum’s director, claimed the whale would remind visitors of humanity’s duty to the environment and the museum’s conservation work. He also stressed the <a href="http://www.standard.co.uk/news/london/natural-history-museum-is-replacing-109yearold-dippy-the-dinosaur-with-more-relevant-installation-10009868.html">importance of the “real and authentic”</a>. A copy, even of a dinosaur, cannot compete with an authentic whale.</p>
<p>The Natural History Museum’s blue whale has a venerable history: acquired in 1891, it became the first blue whale skeleton on public display in 1935. But in books, there were whales on display way before this. </p>
<p>In Herman Melville’s <a href="http://www.powermobydick.com/Moby102.html">Moby-Dick</a> (1851), Ishmael defends his detailed knowledge of sperm whale anatomy by explaining that he was shown a real skeleton by King Tranquo of the Arsacides. Tranquo exhibits his sperm whale alongside “whatever rare things the more ingenious of his people could invent”, including “chiselled shells, inlaid spears, costly paddles”, and the “natural wonders” cast on his shores: in other words, in a museum. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=941&fit=crop&dpr=1 600w, https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=941&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=941&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1182&fit=crop&dpr=1 754w, https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1182&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/70622/original/image-20150130-25921-1vugbj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1182&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Moby Dick.</span>
</figcaption>
</figure>
<h2>Two whales</h2>
<p>In 1850s America such authenticity could not necessarily be expected of museums. PT Barnum’s immensely popular American Museum on Broadway enticed visitors with objects of questionable legitimacy, such as a mummified <a href="http://hoaxes.org/archive/permalink/the_feejee_mermaid">“Fee-jee Mermaid”</a> – the torso and head of a juvenile monkey sewn to half of a fish. Historian <a href="http://www.hup.harvard.edu/catalog.php?isbn=9780674005914">James Cook</a> has argued that visitors’ pleasure came from judging – and perhaps debunking – the veracity of Barnum’s curios. </p>
<p>While Ishmael visits the whale skeleton in a temple, a place of reverence, he explains that there is another sperm whale skeleton on display. This whale is owned by a British aristocrat who has articulated the skeleton for the amusement of paying customers: </p>
<blockquote>
<p>A footman will show round future visitors with a bunch of keys at his side. Sir Clifford thinks of charging twopence for a peep at the whispering gallery in the spinal column. </p>
</blockquote>
<p>Sir Clifford seems to be a reflection of Barnum, charging fees and transforming the whale’s body into an entertainment. His commercial enterprise is in danger of debasing what it displays. Melville sets up a debate between good museums – spaces for the reverence of authentic objects – and bad ones where objects are exploited for entertainment and cash. </p>
<p>But of course, the Natural History Museum is a different kettle of fish. It is free to visit and unlikely to turn its whale into a whispering gallery – so it remains on the virtuous side of Melville’s debate. </p>
<h2>Authentic what?</h2>
<p>Except, Tranquo’s real whale skeleton in its temple is not without problems. Although Ishmael can take accurate measurements of the skeleton, he is forced to confess that “the skeleton of the whale is by no means the mould of his invested form”. So this is a real whale, but not an authentic experience. “Only on the profound unbounded sea, can the fully invested whale be truly and livingly found out,” Ishmael concludes. Melville is clear that the real and the authentic are not necessarily one and the same: real objects do not necessarily lead to authentic experiences. </p>
<p>Curiously, this point is also made by the “Save Dippy” campaign, led by children’s author, James Mayhew. Mayhew says that the whale skeleton is <a href="http://www.independent.co.uk/news/science/save-dippy-natural-history-museum-dinosaur-loses-his-spot-10012090.html">“hard to decipher”</a>, suggesting it will not provoke the same experience of awe as does Dippy, who has a “clear, recognisable shape”. </p>
<p>So perhaps a real whale isn’t any more authentic than a dinosaur cast. Many even see moving the real whale to the entrance hall as an attack on the authentic experience of the museum. Dixon’s desire that the entrance tells a story that is relevant to the Natural History Museum’s current role rubs up against a strong feeling among the public that the museum must keep telling the story of their own first visits. We want museums to not only be repositories for history, but for our own histories as visitors, and especially our childhoods.</p>
<p>This function of museums is poignantly demonstrated by another cultural depiction of a museum whale. In Noah Baumbach’s acclaimed film <a href="http://www.imdb.com/title/tt0367089/">The Squid and the Whale</a> (2005), Walt, a teenage boy, comes to realise the roles his parents played in his upbringing while revisiting the <a href="http://www.amnh.org/exhibitions/permanent-exhibitions/biodiversity-and-environmental-halls/milstein-hall-of-ocean-life/sperm-whale-and-giant-squid">model of a giant squid and giant whale in combat</a> at the American Museum of Natural History in New York. This is even more unreal than the cast of Dippy as it confects a hypothetical encounter between the two creatures. Yet it becomes a scene of both authentic experience and a regression to childhood. </p>
<p>Ultimately, this may be the authenticity we want from museums, rather than the display of real objects. Even Melville notes that some bones from Tranquo’s whale had been stolen by children to play marbles with: “Thus we see how that the spine of even the hugest of living things tapers off at last into simple child’s play.”</p><img src="https://counter.theconversation.com/content/36927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katie McGettigan receives funding from The Leverhulme Trust. She has previously received funding from the AHRC. </span></em></p>The Natural History Museum’s plan to remove “Dippy”, the cast of a diplodocus skeleton, from its entrance hall, and replace it with a genuine skeleton of a blue whale has been met with outrage. The #savedippy…Katie McGettigan, Leverhulme Early Career Fellow in American Studies, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/296212014-07-25T04:35:39Z2014-07-25T04:35:39ZCould this be one reason why whale populations have not recovered following hunt ban?<figure><img src="https://images.theconversation.com/files/54789/original/9rn5qmhr-1406197210.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Few survive a close shave with a ship's propeller.</span> <span class="attribution"><a class="source" href="http://www.nmfs.noaa.gov/stories/2013/04/images/cloudy_with_a_chance_of_whales1_gallery.jpg">Alisa Schulman-Janiger</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>When commercial whaling was banned in 1986 it put an end to a harvest that threatened the existence of some of the most majestic animals on Earth. With several species <a href="http://iwc.int/status">reduced to tiny fractions</a> of their original populations, once the moratorium was introduced the expectation was that whale populations would recover. But in the decades since, only some have.</p>
<p>There are many possible reasons why this might be, including <a href="http://www.nature.com/news/whale-earwax-a-time-capsule-for-stress-and-toxins-1.13750">chemical pollution</a>, <a href="http://www.washingtonpost.com/wp-dyn/content/article/2007/09/10/AR2007091002143.htmlddd">climate change</a>, <a href="http://edition.cnn.com/2012/01/19/opinion/clark-southall-marine/">man-made noise</a>, and <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2007.00175.x/abstract">loss of cultural knowledge among whales</a> that prevent their descendants returning to habitats in their former range. A further risk, highlighted by a new study of blue whales off the coast of California, is deaths and injury caused by being <a href="http://iwc.int/ship-strikes">struck by ships</a>. In most populations, we don’t yet know how big a problem it is, but for some it is <a href="http://www.listenforwhales.org/page.aspx?pid=439">almost certainly holding back recovery</a>.</p>
<p>In recent years <a href="http://news.bbc.co.uk/1/hi/world/americas/8169309.stm">reports</a> of the arrival of large vessels into port with the carcass of a large whale <a href="http://www.portofrotterdam.com/en/News/pressreleases-news/Pages/container-vessel-carries-whale.aspx">pinned</a> to the bow bulb have become a <a href="http://www.adn.com/node/1386076">regular</a> <a href="http://www.theguardian.com/world/2010/jul/30/dead-humpback-whale-alaska-cruise">occurrence</a> in the <a href="http://www.nbcnewyork.com/news/local/Whale-New-York-Harbor-Bow-of-Ship-Liberty-State-Park-255513431.html">news</a>. Of course, these are only those cases that make it to port – an unknown number of strikes leave their victims at sea, and are sometimes <a href="http://www.mirror.co.uk/news/world-news/blue-whale-killed-by-ship-incredibly-828597">encountered by chance</a>.</p>
<p>In fact the impact on the vessel is so insignificant that the crew is typically unaware that it has happened until it reaches port. But why this apparent increase in numbers? Is there just more interest, or are there now more whales to hit, are newer ships somehow more dangerous (modern, more efficient technology is often quieter), or are the whales moving into more dangerous busy shipping lanes? We don’t know, which is why studies like <a href="http://dx.plos.org/10.1371/journal.pone.0102959">one</a> published in the journal PLoS One are so important.</p>
<p>Oregon State University researcher Ladd Irvine and his colleagues attached satellite tags to 171 blue whales over a period of 15 years starting in 1993. For a study of whales this is a huge dataset representing a massive investment, largely in terms of researcher time, and provides a really robust insight into the whale’s habitat use. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=470&fit=crop&dpr=1 600w, https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=470&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=470&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=590&fit=crop&dpr=1 754w, https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=590&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/54689/original/9hfzkzpf-1406135779.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=590&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">Even a blue whale is no match for a speeding ship weighing tens of thousands of tonnes.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/File:Blue_Whale_001_noaa_body_color.jpg">NOAA Fisheries</a></span>
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<p>They found two core areas heavily used by the whales, in the <a href="http://farallones.noaa.gov/">Gulf of the Farralones</a> off San Francisco Bay, and north of the <a href="http://www.nps.gov/chis/index.htm">Channel Islands</a>, near Los Angeles. The whales’ presence there wasn’t year-round, but heavily concentrated between July and October as they followed high concentrations of their food, krill, that accumulate after the spring plankton bloom in these productive waters. Some individuals returned to the same spots at the same times over many years, suggesting the whales relied on their knowledge and sense of location rather than an ability to track prey, highlighting the important role that habitat knowledge plays in these animals’ lives.</p>
<p>By plotting the whale distribution maps against those of heavily-used shipping lanes along the California coast, the problem is clear. The shipping lanes run through some of the areas most heavily used by the whales, putting them at high risk of ship strikes. The shipping lanes are typically placed where they are heavily used and most economical, such as the shortest distance between two points. No shipping companies would change their routes and incur costs without solid evidence of a problem, and this is exactly the kind of evidence this study provides.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=599&fit=crop&dpr=1 600w, https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=599&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=599&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=753&fit=crop&dpr=1 754w, https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=753&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/54692/original/3fg93g8y-1406136506.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=753&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">Plot of four different whale species along the US west coast.</span>
<span class="attribution"><a class="source" href="http://www.nmfs.noaa.gov/stories/2013/04/04_04_13cloudy_with_a_chance_of_whales.html">Bruce Mate/Oregon State University</a></span>
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<p>It’s hard to comprehend in an age when we are <a href="http://www.esa.int/Our_Activities/Space_Science/Mapping_Mars">mapping the surface of Mars</a> just how ignorant we are about these huge ocean creatures. How do you figure out how many blue whales there are in the deeply inhospitable Southern Ocean? Sometimes technology can help, such as the satellite tags used for this study. Shipping lanes into Boston on the eastern US seaboard are <a href="http://www.listenforwhales.org/">now equipped with acoustic buoys</a> that report detections of <a href="http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/rightwhale_northatlantic.htm">critically endangered right whales</a> in near real-time, hopefully reducing significant numbers of deaths from ship strikes.</p>
<p>Of course, we could find out more – it just takes money. The constraint is economic and political, not a lack of technology or ingenuity. Scientists are accumulating evidence that might help us appreciate just how much healthy whale populations could be doing for us. As large, apex predators they structure the ecosystems in which they live, <a href="http://www.esajournals.org/doi/abs/10.1890/130220">they provide ecosystem services</a> by <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0013255">recycling nutrients</a> throughout the water column, and their huge carcasses fuel entire deep-sea ecosystems for years. Even their excrement plays a vital role in fertilising nutrient-poor surface waters, seeding the seas with iron, which boosts phytoplankton growth and potentially plays a part in the <a href="http://www.greenworld.org.uk/Past%20Editions/page280/page287/page287.html">dynamics of climate change</a>. </p>
<p>It seems that marine habitats with healthy whale populations might actually be more productive than ones without. It’s never made more sense to invest in saving the whales.</p><img src="https://counter.theconversation.com/content/29621/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Rendell receives funding from the Marine Alliance for Science and Technology Scotland (masts.ac.uk), and the Leverhulme Trust.</span></em></p>When commercial whaling was banned in 1986 it put an end to a harvest that threatened the existence of some of the most majestic animals on Earth. With several species reduced to tiny fractions of their…Luke Rendell, MASTS Lecturer in Biology, University of St AndrewsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/262622014-05-02T16:08:27Z2014-05-02T16:08:27ZWhat do you do with a whale that won’t explode?<figure><img src="https://images.theconversation.com/files/47650/original/33pqgpsr-1399030668.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If only it didn't stink.</span> <span class="attribution"><a class="source" href="https://twitter.com/DonBradshawNTV/statuses/460529679850414081">Don Bradshaw and NTV</a></span></figcaption></figure><p>The residents of Trout River in Newfoundland, Canada have a stinking whale of a problem. What to do with the 81-feet-carcass of <em>Balaenoptera musculus</em> on their shore?</p>
<p>While such an occurrence is not uncommon, the blue whale of Trout River is a worry because some dead marine mammals can explode. In 2013 an exploding sperm whale was recorded on camera.</p>
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<p>In 2004, in the hope of studying it, Chinese scientists decided to move the carcass of a 60-ton sperm whale through the city of Tainan, Taiwan. While on the tractor-trailer, the sperm whale exploded, showering stores, cars and onlookers <a href="http://qz.com/204651/sometimes-the-best-way-to-get-rid-of-a-dead-whale-is-to-blow-it-up/">with whale insides</a>.</p>
<p>Whales explode because of gas buildup in their abdominal cavity. When mammals die, their last meals start to rot. For the gut bacteria digesting that rot, it provides a tasty meal. But the digestion process releases methane gas, which makes the whale bloat and sometimes explode.</p>
<h2>Gut reaction</h2>
<p>I have a vexed relationship with exploding whales. On the one hand, I have a visceral disgust for mammal anatomy, to a near debilitating degree. I walked an extra block in college just to avoid going through the vertebrate anatomy lab. I had to leave the only mammal dissection I ever attended because I couldn’t stop gagging. And yet, despite all this, I will stop whatever I am doing to watch an exploding whale video, with disgust and fascination.</p>
<p>And I am not alone. Millions of people worldwide are obsessed with this cetacean time bomb. To capitalise on this, scientists decided to create a very different kind of whale watching experience. <a href="http://HasTheWhaleExplodedYet.com">HasTheWhaleExplodedYet.com</a> allows you to receive regular updates on the state of the ballooning carcass. </p>
<p>I, like many others, want so badly for the whale to explode. But sadly, it doesn’t look like it will happen. The carcass has begun to deflate. This is because, unlike the exploding sperm whale of 2013, blue whales are built for this.</p>
<p>As lung-filter feeders, blue whales make a living by withstanding massive internal pressure. When blue whales find a school of krill, they open their jaw wide-open, and fill a specialised abdominal cavity at a rate of 20 tonnes of water per second. This makes the blue whale, unlike the exploding sperm whale, a tough balloon. </p>
<h2>Post-mortem</h2>
<p>Something needs to be done about the carcass to stop the stench. In 1970, when faced with the same problem, the Orgeon State Highway Division decided to blow up the whale with dynamite. The event cannot be termed a complete success. Onlookers hundreds of feet away were showered with whale blubber and a car was destroyed. But the TV news coverage of the event is probably some of the best ever produced.</p>
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<p>So, given the lessons of the past, the residents of Trout River should be pleased by the Royal Ontario Museum’s decision to <a href="http://www.cbc.ca/news/canada/newfoundland-labrador/whale-carcasses-to-be-removed-by-royal-ontario-museum-1.2628116">remove the carcass</a> for study. If successful, they will get rid of the stink without a whale-blubber shower.</p><img src="https://counter.theconversation.com/content/26262/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Helm 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 residents of Trout River in Newfoundland, Canada have a stinking whale of a problem. What to do with the 81-feet-carcass of Balaenoptera musculus on their shore? While such an occurrence is not uncommon…Rebecca Helm, Ph.D. Candidate, Brown UniversityLicensed as Creative Commons – attribution, no derivatives.