tag:theconversation.com,2011:/global/topics/monkeys-4313/articlesMonkeys – The Conversation2024-02-20T14:31:08Ztag:theconversation.com,2011:article/2224752024-02-20T14:31:08Z2024-02-20T14:31:08ZDefying expectations, disabled Japanese macaques survive by adjusting their behaviours and receiving support<figure><img src="https://images.theconversation.com/files/576169/original/file-20240216-30-6btxw6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5184%2C3453&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A disabled young female macaque named Monmo at the Awajishima Monkey Center in Japan.</span> <span class="attribution"><span class="source">(Sarah E. Turner)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Nina is a Japanese macaque, one of the red-faced monkeys famous for sitting in hot springs in Japan. Nina lives wild in the forest, but most days, along with her group, she visits the <a href="https://monkey-center.jp/english.php">Awajishima Monkey Center</a> to eat the food people provide for the monkeys. </p>
<p>Nina was born without hands, <a href="https://doi.org/10.1007/s10329-008-0083-4">an unusually common occurrence in this group of macaques</a>. While no one knows for sure why these malformations of the limbs and digits occur, many researchers have suggested a potential link to pesticides or <a href="https://doi.org/10.1007/%20s10329-014-0405-7">other environmental contaminants</a>. </p>
<p>Nina survived because of a combination of factors: her ability to modify her behaviours to compensate for her physical impairments; the extra care provided by her mother when she was little; and living in a group of monkeys who treat her much <a href="https://doi.org/10.1016/j.jhevol.2014.01.002">the same way they do non-disabled group members</a>.</p>
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<a href="https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an infant and older macaque in the middle of the road" src="https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=657&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=657&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=657&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=826&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=826&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576171/original/file-20240216-18-i4irp6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=826&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">Nina, a juvenile disabled female Japanese macaque at the Awajishima Monkey Center, sitting with an older Juvenile.</span>
<span class="attribution"><span class="source">(Brogan M. Stewart)</span></span>
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<p>Over the years, we have spent many hours observing Nina and other disabled and non-disabled monkeys, as they live their lives — moving through the forest, socializing with others in their group and finding novel ways of adjusting their behaviours to compensate for physical impairments. </p>
<p>Disability is a <a href="https://www.un.org/development/desa/disabilities/resources/factsheet-on-persons-with-disabilities.html">normal part of human experience</a>, with at least <a href="https://www.who.int/news-room/fact-sheets/detail/disability-and-health">16 per cent of people experiencing some form of disability</a>. However, while conducting research at Awajishima, we have noticed that many people expect that disabled animals would be unlikely to survive. However, Nina and other disabled macaques in her group can survive and reproduce, and are far from being alone among primates of the world. </p>
<h2>Primates and disability</h2>
<p>In a recently published review of the literature on non-human primates and disability in the <em>American Journal of Primatology</em>, we found that <a href="https://doi.org/10.1002/ajp.23579">physical impairment is more common among wild and free-ranging primates than most people might think</a>. </p>
<p>We found 114 published papers on primates with disability, not including all the casual observations and field notes that were not published in the scientific literature. These papers included 37 species of non-human primates — monkeys, apes and lemurs — from 70 different study sites (38 of those with wild and free-ranging primates).</p>
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<span class="caption">Disabled and non-disabled monkeys hanging out and socially grooming at the Awajshima Monkey Center in Japan.</span>
<span class="attribution"><span class="source">(Sarah E. Turner)</span></span>
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<p>About 45 per cent of these disabilities, like Nina’s, were present from birth, while approximately 24 per cent came from injury, with similar frequency caused by a condition or illness. </p>
<p>Behavioural flexibility or plasticity (the ability to modify activities and actions in response to specific circumstances), the innovation of novel behaviours and extra maternal care stood out in the published research papers.</p>
<p>Seventy papers reported on ways that primates used behavioural flexibility and innovations to compensate for physical impairments, or provided examples of mothers who were able to support the needs of their physically impaired offspring. There were also some instances of other relatives and group members also providing support. </p>
<p>Overall, there was little evidence of social selection against disabled primates. There were also many examples of undifferentiated treatment for disabled individuals, and a few examples of disability-associated care behaviours.</p>
<h2>Human causes of primate disability</h2>
<p>Having studied disabled monkeys, we were not surprised to learn about the behavioural plasticity we found in this review. What was more surprising to us was just how many of these disabilities were linked to anthropogenic activities. </p>
<p>There are many ways that human activities can lead directly and indirectly to long-term disability in our closest animal relatives. Sixty per cent of the published examples of primate disability we surveyed were linked to human causes. </p>
<p>These included: injuries from <a href="https://doi.org/10.1046/j.1365-2028.2002.00356.x">hunting snares among chimpanzees and gorillas</a>; injuries sustained on <a href="https://doi.org/10.1007/s10764-014-9779-z">roads or from electrical wires in South African baboons</a> and <a href="https://doi.org/10.1896/044.014.0206">South American howler monkeys</a>; and the effects of <a href="https://doi.org/10.1098/rstb.1985.0020">diseases transmitted between human and non-human primates</a>.</p>
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<a href="https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a monkey with a malformed hand in the foreground, other monkeys in the background" src="https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=713&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=713&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=713&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=896&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=896&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576599/original/file-20240219-21-gxzmo5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=896&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 disabled infant macaque with her mother in the background at the Awajishima Monkey Center in Japan.</span>
<span class="attribution"><span class="source">(Sarah E. Turner)</span></span>
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<h2>Human pressure, increasing threats</h2>
<p>At a time when the majority of non-human primates are experiencing declining populations and <a href="https://doi.org/10.1126/sciadv.abn2927">are threatened with extinction</a>, this link between human activities and physical impairments in primates is a poignant reminder of how humans are impacting other life on Earth. </p>
<p>Wherever non-human primates are found in the world — throughout the tropics and as far north as Japan — they face compounding threats from human pressures. As humans increasingly convert forests and wild lands to agricultural and urban spaces, habitat loss is pushing many <a href="https://doi.org/10.1126/sciadv.1600946">primate species towards extinction</a>. </p>
<p>These pressures are exacerbated by resource extraction (often to meet market demand from the Global North), hunting, the exotic pet trade and disease. The threat of major impacts from <a href="https://doi.org/10.1007/s10584-020-02776-5">climate change is also looming on the horizon</a>. Even the most behaviourally flexible, smart, care-giving and innovative of individuals and species may not be able to navigate the scope and variety of these changes and pressures.</p>
<p>Physically impaired and disabled primates often find ways to behaviourally compensate for their impairments, survive and reproduce. </p>
<p>Nina and her friends show us an important side of non-human primate behaviour, giving us a model to examine the capacity for behavioural flexibility in nonhuman primates. Our research also underscores the critical role that humans have in shaping the futures of our closest animal relatives.</p><img src="https://counter.theconversation.com/content/222475/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah E. Turner receives funding from the Natural Sciences and Engineering Research Council of Canada - Leadership in Environmental and Digital innovation for Sustainability (LEADS-CREATE), Fonds de recherche du Québec ‐ Nature et technologies, MITACS Globalink Research Awards, the Quebec Centre for Biodiversity Science, and Concordia University.</span></em></p><p class="fine-print"><em><span>Brogan M. Stewart receives funding from NSERC - Alexander Graham Bell and CREATE in the Leadership in Environmental and Digital innovation for Sustainability (LEADS), FRQNT, Concordia University, Kyoto University, Quebec Centre for Biodiversity Science, and MITACS Globalink.</span></em></p><p class="fine-print"><em><span>Jack Creeggan receives funding from MITACS Globalink, Quebec Centre for Biodiversity Science, Concordia University, and NSERC-CREATE in Leadership in Environmental and Digital innovation for Sustainability (LEADS).</span></em></p><p class="fine-print"><em><span>Megan M. Joyce receives funding from MITACS Globalink, Quebec Centre for Biodiversity Science, Concordia University, and NSERC-CREATE in Leadership in Environmental and Digital innovation for Sustainability (LEADS).</span></em></p><p class="fine-print"><em><span>Mikaela Gerwing receives funding from Miriam Aaron Roland Graduate Fellowship, Concordia University, and NSERC - CGS M and CREATE in Leadership in Environmental and Digital innovation for Sustainability (LEADS).</span></em></p><p class="fine-print"><em><span>Stephanie Eccles receives funding from FRQSC and NSERC‐CREATE in Leadership in Environmental and Digital innovation for Sustainability (LEADS).</span></em></p>A community of macaques in Japan has a high rate of disabled individuals who survive with behavioural flexibility and maternal care. Globally, primate disabilities are often related to human causes.Sarah E. Turner, Associate Professor, Geography, Planning and Environment, Concordia UniversityBrogan M. Stewart, PhD Student in Environmental Science, Concordia UniversityJack Creeggan, Master's Student in Geography, Planning, and Environment, Concordia UniversityMegan M. Joyce, PhD Student in the Department of Geography, Planning and Environment, Concordia UniversityMikaela Gerwing, Wildlife Conservation Biologist and PhD Student, Concordia UniversityStephanie Eccles, PhD Candidate, Department of Geography, Planning, and Environment, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202182024-02-04T22:56:09Z2024-02-04T22:56:09ZOur ancient primate ancestors had an appetite for soft fruits – and their diet shaped human evolution<p>The diet of early anthropoids – the ancestors of apes and monkeys – has long been debated. Did these early primates display behaviours and diets similar to modern species, or did they have much humbler beginnings? </p>
<p>Research on early anthropoids has often suggested a diet high in soft fruits. But some species seem to have had a more varied diet, containing harder foods such as seeds and nuts. </p>
<p>Our <a href="https://doi.org/10.1002/ajpa.24884">latest research</a> reveals a different story, one that highlights the dominant role of soft fruits. This likely encompassed various types that were ripe and high in sugar, as evidenced by the presence of tooth decay in some individuals.</p>
<p>This has important implications for understanding how our earliest ancestors adapted and evolved.</p>
<h2>Tracking anthropoid evolution</h2>
<p>When discussing the primate family tree, it is crucial to address the common confusion arising from the everyday use of terms such as “ape” and “monkey”. </p>
<p>Humans, for instance, are typically excluded from the ape category, and apes are not generally considered monkeys. Yet humans are nested within the ape family tree, which in turn is nested within the broader monkey group, however this is defined.</p>
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<a href="https://theconversation.com/revelations-from-17-million-year-old-ape-teeth-could-lead-to-new-insights-on-early-human-evolution-187996">Revelations from 17-million-year-old ape teeth could lead to new insights on early human evolution</a>
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<p>All of these primates (humans, apes, and monkeys) are collectively called anthropoids, and we all share a common anthropoid ancestor that lived around 40 million years ago.</p>
<p><a href="https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1001342">Genetic and molecular studies</a>, along with <a href="https://www.pnas.org/doi/abs/10.1073/pnas.0908320107">fossil evidence</a>, indicate the period from 40 to 25 million years ago was a critical phase for the evolution and spread of anthropoid primates. </p>
<p>The early portion of this period marks when Afro-Eurasian monkeys and apes (Catarrhini) diverged from monkeys native to the Americas (Platyrrhini). The latter part of this period witnessed further divergence between Afro-Eurasian monkeys (Cercopithecoidea) and apes (Hominoidea).</p>
<h2>Fossils of our earliest ancestors</h2>
<p>The <a href="https://link.springer.com/chapter/10.1007/978-3-319-65661-8_12">Fayum Depression</a> in the Western Desert of Egypt offers one of the largest and best-preserved collections of fossil primates from this time frame. Between 35 and 29.2 million years ago (when the fossils used in this study were deposited), the Fayum sat on the lush northern coast of Africa. </p>
<p>The terrestrial rocks of the Fayum preserve the remnants of ecosystems that laid the groundwork for Africa’s modern biodiversity. They also capture a pivotal window in primate evolution. </p>
<p>Several of the anthropoid primates from the site may represent either the direct ancestors of all (or some) living anthropoids. Or they were close relatives of this common ancestor. </p>
<p>Fossils of these early anthropoids are relatively abundant in the Fayum, with some species known from dozens of partial skulls and jaws. Because of this, the Fayum offers a fascinating glimpse into the behaviour and life of our early ancestors.</p>
<h2>Dietary interpretations</h2>
<p>Dental evidence is a powerful tool in palaeontology. Our new study examined dental wear and disease in fossilised teeth from five Fayum anthropoid primates: <em>Aegyptopithecus</em>, <em>Parapithecus</em>, <em>Propliopithecus, Apidium</em> and <em>Catopithecus</em>. </p>
<p>We focused on tooth chipping patterns and dental caries (also known as cavities), key indicators in fossils of dietary habits.</p>
<p>Our findings indicate a predominantly soft fruit diet in early anthropoids, different to some earlier research suggesting a more varied diet, including hard foods. </p>
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<a href="https://theconversation.com/human-ancestors-had-the-same-dental-problems-as-us-even-without-fizzy-drinks-and-sweets-92546">Human ancestors had the same dental problems as us – even without fizzy drinks and sweets</a>
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<p>A mere 5% of teeth show chipping (minor enamel fractures). This is substantially lower than the frequency observed in most modern anthropoids, where chipping frequencies range from 4% to 40% of teeth. </p>
<p>Additionally, the presence of dental caries, notably in Propliopithecidae (the extinct primate family that includes <em>Aegyptopithecus</em> and <em>Propliopithecus</em>), is consistent with the regular consumption of soft, sugary fruits. </p>
<p>This research also lends support to previous studies suggesting an arboreal (tree-living) lifestyle for early anthropoids. Terrestrial primates often exhibit higher chipping prevalence due to more varied diets and accidental grit consumption when feeding on the ground, none of which was evident in our findings. </p>
<h2>Adaptation and evolution</h2>
<p>The preference for soft fruits likely had significant impacts on exploration of ecological niches, and even in the development of eyesight in anthropoid primates. This includes colour vision that likely evolved as a need for <a href="https://www.jstor.org/stable/3066998">finding ripe fruit among the foliage</a>. </p>
<p>It would have also influenced the shape of their teeth, social behaviours and foraging strategies, setting the stage for an adaptive radiation, leading to the global spread and diversification of monkeys and apes. </p>
<p>This rapid evolution of diverse species from humble anthropoid beginnings was likely in response to new ecological opportunities opening up.</p>
<p>Other primates more distantly related to us, in the primate suborder Strepsirrhini, which includes lemurs and lorises, split off from the ancestors of anthropoids millions of years earlier. </p>
<p>Unlike anthropoids, Strepsirrhini show a large variation in diet during the same time interval. The diets of fossil lemurs and lorises likely consisted of hard and tough foods, insects, gum, leaves and fruits. </p>
<p>In contrast, our own ancestors took a long time to move away from a diet based on soft fruits. Our journey into the past to unravel the lives of our ancestors continues, with each fossil adding a new piece to the puzzle of early primate evolution.</p><img src="https://counter.theconversation.com/content/220218/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Robert Borths receives funding from the United States National Science Foundation and the Institute for Museum and Library Services. </span></em></p><p class="fine-print"><em><span>Carolina Loch and Ian Towle 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>New fossil studies tell us our ancient ancestors enjoyed a diet of soft, sweet fruits. This would have influenced where they lived and spread to – and even the evolution of colour vision.Carolina Loch, Senior Lecturer in Oral Biology, University of OtagoIan Towle, Postdoctoral researcher, Centro Nacional de Investigación sobre la Evolución Humana (CENIEH)Matthew Robert Borths, Curator of the Duke Lemur Center Museum of Natural History, Duke UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2215472024-01-31T12:02:05Z2024-01-31T12:02:05ZWhy monkeys attack people – a primate expert explains<figure><img src="https://images.theconversation.com/files/570907/original/file-20240123-15-jwdv0w.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5159%2C3429&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/monkeys-open-mouth-see-horrible-teeth-1156580965">Witsawat.S/Shutterstock</a></span></figcaption></figure><p>Wildlife tourism thrives on our fascination with animals and primates are particularly attractive animals to tourists. With their human-like faces, complex family dynamics and acrobatic antics, they are a joy to behold.</p>
<p>But recent stories have emerged that portray monkeys in a more sinister light. Reports of <a href="https://www.theguardian.com/world/2022/jul/25/monkey-attacks-injure-people-japanese-city-yamaguchi-tranquilliser-gun">“monkey attacks”</a>, <a href="https://metro.co.uk/video/devil-monkeys-push-driver-160ft-hillside-attack-thailand-2994905/">“devil monkeys”</a>, or even <a href="https://www.dailystar.co.uk/news/latest-news/what-face-ripping-bone-biting-31631055">“face-ripping, bone-biting monkeys”</a> have become common in the media. Have our primate cousins turned on us?</p>
<p>The recent monkey attacks involve a variety of species in different countries. They include the <a href="https://metro.co.uk/2024/01/16/thailand-monkeys-turn-tourists-start-attacking-beach-20120135/">long-tailed macaque</a> and the <a href="https://metro.co.uk/2023/08/09/thailand-devil-monkeys-pushed-driver-down-hill-and-attacked-him-19307282/">pig-tailed macaque</a> in Thailand, <a href="https://www.theguardian.com/world/2022/jul/25/monkey-attacks-injure-people-japanese-city-yamaguchi-tranquilliser-gun">Japanese macaques</a> in Japan, and <a href="https://www.businessinsider.com/boy-killed-monkey-attack-india-intestines-ripped-2023-11?r=US&IR=T">Hanuman langurs</a> in India.</p>
<p>Most of these species are macaques, which are a diverse group of monkeys. But all macaques are sociable, intelligent, relatively large (between 4kg and 9kg), and comfortable travelling on the ground. They have a flexible diet, but prefer fruit. They also have cheek pouches that allow them to gather food quickly and carry it to a safe place to eat.</p>
<h2>Over-habituation</h2>
<p>Regardless of species or location, a major factor in monkey bites and attacks is “over-habituation”. Habituation is a process used by animal researchers to gain animals’ trust so they can follow and record their behaviour, with limited impact of the researchers’ presence. </p>
<p>But animals can become unintentionally habituated. Squirrels in a city park who have grown accustomed to handouts are one example, but others include urban foxes in the UK, bears in North America, and, in many parts of the tropics, monkeys.</p>
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<a href="https://theconversation.com/three-surprising-reasons-human-actions-threaten-endangered-primates-197850">Three surprising reasons human actions threaten endangered primates</a>
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<p>When animals lose their fear of humans and become a nuisance, they are over-habituated. In nearly all cases of over-habituation, the main factor is human food. What people eat is irresistible to wildlife. It is nutrient-dense, easy to digest and is available in rubbish bins, unattended backpacks, or even directly from people. </p>
<p>From an ecological point of view, animals have every incentive to take advantage of this high-quality resource. So, it’s no surprise that animals will adjust their fear and natural behaviour accordingly.</p>
<p>While over-habituation due to associating tourists with food is certainly the main driver for the reported monkey attacks, that does not mean that every person bitten or threatened by a monkey is guilty of feeding or teasing them. </p>
<figure class="align-center ">
<img alt="A long-tailed macaque sits on a red footbridge while a cyclist rides past." src="https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572224/original/file-20240130-23-bkbzlc.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 contemplative long-tailed macaque in Singapore.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/long-tailed-macaques-crossing-bridge-singapore-2364831037">Tan Yong Lin/Shutterstock</a></span>
</figcaption>
</figure>
<p>Monkeys are very smart, have a long memory and learn from each other. Many groups have grown so accustomed to human foods that they have learned to harass tourists to get it. Some monkeys have become so adept at this that they know which items are valuable to tourists, which they will <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2019.0677">“trade” for food</a>. In other words, they’ll steal your mobile phone but then drop it when you throw them some food. </p>
<p>Another important factor in monkey attacks at tourist sites is an unawareness of the animals’ body language, facial expressions and vocalisation. Even highly habituated monkeys will normally give a warning before attacking someone. But people inexperienced with monkey behaviour will often <a href="https://peerj.com/blog/post/115284879374/experience-based-human-perception-of-facial-expressions-in-barbary-macaques/">misinterpret</a> a threatening facial expression for a friendly one. This can lead to dangerous encounters.</p>
<h2>Advice</h2>
<p>Wildlife tourists cannot be expected to understand every species’ typical expressions and body postures. But some things can help tourists be more safe and responsible, regardless of the primate species they are viewing.</p>
<ol>
<li><p>Give them space. According to the <a href="https://human-primate-interactions.org/responsible-primate-watching-for-tourists/">International Union for Conservation of Nature</a>, a network of environmental organisations, keeping a distance of seven metres (23 feet) from the animals is recommended. This helps the animals not feel threatened and also reduces the risk of disease transmission.</p></li>
<li><p>Do not stand between the animals and their route to safety, or between adults and young.</p></li>
<li><p>Avoid direct eye contact or showing your teeth because monkeys may perceive this as aggressive.</p></li>
<li><p>For many primate species, common threats include bared teeth (including some yawns), direct stares with a lowered head, and short lunges or slapping the ground with the hands. If an animal does any of these things, quietly back away.</p></li>
<li><p>Do not feed the monkeys.</p></li>
</ol>
<p>Wildlife tourism contributes <a href="https://wttc.org/Portals/0/Documents/Reports/2019/Sustainable%20Growth-Economic%20Impact%20of%20Global%20Wildlife%20Tourism-Aug%202019.pdf">more than US$100 billion</a> (£786 billion) per year to the global economy. It is also immensely rewarding and can offer many benefits to wildlife and the communities of people who live near them. But we should all be <a href="https://theconversation.com/five-ways-to-be-a-responsible-wildlife-tourist-118869">responsible tourists</a>.</p><img src="https://counter.theconversation.com/content/221547/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tracie McKinney is affiliated with the IUCN SSC Primate Specialist Group's Section for Human-Primate Interactions (SHPI).</span></em></p>Tourists can do a number of things to avoid dangerous encounters with monkeys.Tracie McKinney, Senior Lecturer in Biological Anthropology, University of South WalesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2150912023-11-16T17:39:18Z2023-11-16T17:39:18ZBig cats eat more monkeys in a damaged tropical forest – and this could threaten their survival<figure><img src="https://images.theconversation.com/files/559973/original/file-20231116-22-j4ct25.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5993%2C4000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A jaguar in the jungle of southern Mexico.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/jaguar-jungle-southern-mexico-2205608235">Mardoz/Shutterstock</a></span></figcaption></figure><p>Monkeys are not usually a popular menu item for big cats. Primates are, after all, hard to catch: living in the canopies of large trees and rarely coming down to the ground. Jaguar and puma have varied diets and will normally hunt the species that are most common where they live, such as deer, peccary (a type of wild pig) and armadillo.</p>
<p>But jaguar and puma living in southern Mexican forests with a high human footprint (where wood and other resources are regularly harvested and there are large clearings for farms or expanding settlements) seem to be changing their feeding preferences to include more monkeys, according to <a href="https://onlinelibrary.wiley.com/doi/10.1111/btp.13253">new research</a>.</p>
<p>Other <a href="https://www.researchgate.net/profile/Bart-Harmsen/publication/227643029_The_food_habits_of_jaguars_and_pumas_across_a_gradient_of_human_disturbance/links/5a4b45c2a6fdcce1972198fa/The-food-habits-of-jaguars-and-pumas-across-a-gradient-of-human-disturbance.pdf">studies</a> have already found that when there is less of their usual prey around, big cats turn to alternatives. The changes in jaguar and puma diets that my colleagues and I recorded may indicate that the populations of these normal prey are shrinking, or that something in the environment has changed to make catching and eating primates easier. </p>
<p>This change in the diet of large cats could make the disappearance of primate populations in tropical forests like this one in southern Mexico more likely. This would, in turn, make the disappearance of large cats themselves more likely due to a lack of food, threatening the stability of an entire ecosystem.</p>
<h2>On the trail of big cats</h2>
<p>When forests are cut down or altered by loggers and hunters, primates are particularly affected, as many species depend on tall trees for food, shelter and to chart paths through the forest. Globally, more than 60% of primate species are <a href="https://www.science.org/doi/10.1126/sciadv.1600946">threatened with extinction</a>.</p>
<p>These changes to forests have also put large predators at risk. Understanding what is happening in these areas can inform more effective conservation measures, which may prevent species from disappearing.</p>
<p>The Uxpanapa valley in southeastern Mexico is one of the last relicts of tall evergreen forest in the country, and is classified as <a href="https://fundacioncarlosslim.org/conoce-trabajo-la-alianza-wwf-fundacion-carlos-slim-en-selva-zoque/">one of the most biodiverse</a> areas in both Mexico and the world. It is home to jaguar, puma and many other species, including two endangered primates: howler and spider monkeys.</p>
<figure class="align-center ">
<img alt="A black monkey in a tropical forest canopy." src="https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559978/original/file-20231116-29-ab8f1.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">Howler monkeys are native to South and Central American forests.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mantled-howler-monkey-alouatta-palliata-beautiful-2301090257">David Havel/Shutterstock</a></span>
</figcaption>
</figure>
<p>I led a research team that studied the distribution of primates in the Uxpanapa Valley for the first time. We recorded the number of primates and where they were found, as well as the type of forest they preferred.</p>
<p>Another team looked for large cats with the help of a dog which could detect their faeces, otherwise known as scat. Scat was collected to obtain DNA and determine the species that left it, whether it had any parasites, and what its diet was like. The team found out what prey these large cats were eating by using microscopes to study the hairs left in each scat. Special identification guides can link each kind of animal to its hair – each has a particular colour, pattern and shape.</p>
<p>Large carnivores maintain biodiversity and the functioning of an ecosystem by controlling populations of certain species – for example, herbivores that might otherwise harm trees or prevent forests regrowing. The presence of such predators can indicate an ecosystem’s health. Knowing what top predators are eating can tell us even more about how an ecosystem is functioning.</p>
<h2>What we found</h2>
<p>When we combined the data and information we collected, we began to understand that something out of the ordinary was happening.</p>
<p>Primates were the most frequent prey found in jaguar and puma scats, making up nearly 35% of the remains. Primate remains were also more likely to be found in scats collected from areas with less forest. Spider monkey remains, for example, were more likely to be found in scats collected in areas with more villages, and in forest that was regrowing after being disturbed.</p>
<p>A possible explanation is that where there are more villages, it is likely that there is more hunting and tree-cutting taking place. Where there is more hunting, the prey that jaguar and puma usually prefer might not be as plentiful. And regrowing forests do not offer primates the same protection as tall, untouched forests. These two factors may explain why large cats are eating spider monkeys more often here.</p>
<p>Jaguar and puma will usually eat the prey that is more abundant. If their preferred prey is scarce, they will hunt the species they encounter most. Similar to what we observed with spider monkeys, in areas where there was less tall forest, howler monkey remains were more likely than non-primate prey to be found in the scats, possibly as big cats found it easier to reach primates.</p>
<figure class="align-center ">
<img alt="A pile of logs in a deforested Mexican plain." src="https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559982/original/file-20231116-25-9rnkm0.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">
<figcaption>
<span class="caption">Logging robs monkeys of hiding places from predators.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/illegal-logging-indigenous-communities-chiapas-mexico-1710243550">Eduardo Cota/Shutterstock</a></span>
</figcaption>
</figure>
<p>Less tree cover and overhunting of other prey (combined with general habitat loss) could explain the high rates of primate predation we discovered. Nevertheless, we need to continue monitoring these sites to fully understand these changes in large cat diets.</p>
<p>Our results highlight the importance of maintaining tall forest cover to ensure primates and other forest-dependent species can survive. They also raise the urgent need for conservation, before the negative effects of human activities on both primate and large cat populations become irreversible, and the ecosystems they live in are lost.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<hr><img src="https://counter.theconversation.com/content/215091/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aralisa Shedden received funding from the Mexican Council for Research (CONACyT).</span></em></p>The results could indicate populations of more typical prey in southern Mexico are shrinking.Aralisa Shedden, Postdoctoral Researcher in Conservation, Bournemouth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2123082023-10-17T15:29:28Z2023-10-17T15:29:28ZHow animal traits have shaped the journey of species across the globe<p>The devastating <a href="https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/event-more-info/5413">tsunami</a> that hit Japan in March 2011 set off a series of events which have long fascinated scientists like me. It was so powerful that it caused 5 million tonnes of debris to <a href="https://marinedebris.noaa.gov/japan-tsunami-marine-debris/monitoring-tsunami-debris-north-american-shorelines">wash</a> into the Pacific – 1.5 million tonnes remained afloat and started drifting with the currents. </p>
<p>One year later, and half a world away, debris began washing ashore on the west coast of North America. More than 280 Japanese coastal species such as mussels, barnacles and even some species of fish, had <a href="https://www.science.org/doi/full/10.1126/science.aao1498?casa_token=YwHfCNElf14AAAAA:zJj4eY3uUm2_m4ZH5YzIO6ecvSWdVa_53yZk0ycnxm1Ga3bPLTl5Z6hCbUhvsmA4d0KSPHFPKz84nQ">hitched a ride</a> on the debris and made an incredible journey across the ocean. These species were still alive and had the potential to establish new populations. </p>
<p>How animals cross major barriers, such as oceans and mountain ranges, to shape Earth’s biodiversity is an intriguing topic. And a new <a href="https://www.nature.com/articles/s41559-023-02150-5">study</a> by my collaborators and I has shed light on this process, revealing how animal characteristics such as body size and life history can influence their spread across the globe.</p>
<p>We know that such dispersal events occur in terrestrial species as well. For instance, at least 15 green iguanas <a href="https://www.nature.com/articles/26886">journeyed</a> more than 200km (124 miles) from Guadeloupe to Anguilla in the Caribbean in 1995. They arrived on a mat of logs and trees (likely uprooted through a hurricane), some of which were more than 9 metres (20 feet) long. </p>
<h2>The role of animal characteristics in dispersal</h2>
<p>When animals move across major barriers it can have a big impact on both the new and old locations. For example, an invasive species can arrive in a new area and compete with native species for resources. However, those consequences can be even greater over longer periods of time.</p>
<p>The movement of monkeys from Africa to South America around 35 million years ago led to the evolution of more than 90 species of <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-anthro-102116-041510?casa_token=CZtEoQ5Z9bMAAAAA%3AX9JrgVyGxxegDXgVTUPNHZboMldBec1egagn5S4pLwx4yudreF4L6Q6zG4jUeB9tMxJEIy4q67iX&journalCode=anthro">New World monkeys</a>, including tamarins, capuchins and spider monkeys. And a few chameleons rafting on vegetation from Africa to Madagascar is why we find half of all living <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2013.0184">chameleon</a> species there today.</p>
<p>These events were long thought to be determined by chance – the coincidence of some chameleons sitting on the right tree at the right time. However, <a href="https://www.jstor.org/stable/pdf/24529638.pdf?casa_token=NyxiUsFXod0AAAAA:9aBvrCPO0om98AjWOfs482QWf5eQxRUwKt95p4S3trPy1CQ2CM4K0AJeMBtsNKwKST8ILswcwdjQBRq8ZpdR5-3KL3gOn9uYZHOjzDdPyTm4R3Dom1o">some scientists</a> have suggested there might be more to it. They hypothesised there could be more general patterns in the animals that reach their destination successfully, related to certain characteristics.</p>
<p>Could body size affect how far a species can travel? Animals with more fat reserves may be able to travel longer distances. Or could it be how a species reproduces and survives? For example, animals that lay many eggs or mature early may be more likely to establish a new population in a new place.</p>
<p>But despite a vigorous theoretical debate, the options to test these hypotheses were limited because such dispersal events are rare. Also, the right statistical tools were not available until recently.</p>
<p>Thanks to the recent development of new <a href="https://academic.oup.com/sysbio/article/69/1/61/5490843">biogeographical models</a> and the great availability of data, we can now try to answer questions about how tetrapod species (amphibians, reptiles, birds and mammals) have moved around the globe over the past 300 million years and whether successful species share any common characteristics.</p>
<p>These models allow us to estimate the movements of species’ ancestors while also considering their characteristics. We used these models to study 7,009 species belonging to 56 groups of tetrapods.</p>
<h2>What we found</h2>
<p>For 91% of the animal groups we studied, models that included species characteristics were better supported than models that didn’t. This means that body size and life history are closely linked to how successful a species is at moving to and establishing itself in a new location.</p>
<p>Animals with large bodies and fast life histories (breeding early and often, like water voles) generally dispersed more successfully, as expected. However, there were some exceptions to this rule. In some groups, smaller animals or animals with average traits had higher dispersal rates.</p>
<p>For example, small hummingbirds dispersed better than larger ones, and poison dart frogs with intermediate life histories dispersed better than those with very fast or very slow life histories.</p>
<p>We investigated this variation further and found that the relationship between body size and movement depended on the average size and life history of the group. Our results show that the links between characteristics and dispersal success depend on both body size and life history, and that these cannot be considered separately. </p>
<p>Groups in which small size was an advantage were often already made up of small species (making the dispersal-prone species even smaller), and these species also had fast life histories. We found this to be true for the rodent families <a href="https://www.britannica.com/animal/Muridae"><em>Muridae</em></a> and <a href="https://nhpbs.org/wild/cricetidae.asp"><em>Cricetidae</em></a>. </p>
<p>But groups in which dispersers had intermediate body sizes generally had slow life histories (meaning they had low reproductive output but long lifespans). This means the combination of small body size and slow life history is very unlikely to be an advantage for dispersal across major barriers such as oceans.</p>
<h2>It’s not just chance</h2>
<p>It is amazing to think that rare dispersal events, which can lead to the rise of many new species, are not completely random. Instead, the intrinsic characteristics of species can shape the histories of entire groups of animals, even though chance still may play an important role.</p>
<p>At the same time, two of the most important <a href="https://zenodo.org/record/3553579">environmental challenges</a> of our time are related to movement across major barriers: biological invasions and species’ responses to climate change. On a planet facing rapid changes, understanding how animals move across barriers is therefore crucial.</p><img src="https://counter.theconversation.com/content/212308/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>While working on this study, Sarah-Sophie Weil was affiliated with Université Grenoble Alpes (France) and Swansea University (Wales, UK) who supported her through Initiative d’excellence (IDEX) International Strategic Partnership and Swansea University Strategic Partner Research (SUSPR) scholarships.</span></em></p>New research looks at how different species have managed to cross geographic barriers throughout history and whether their individual traits played a crucial role in these journeys.Sarah-Sophie Weil, PhD candidate, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126702023-09-08T18:15:46Z2023-09-08T18:15:46ZG20 summit’s plan to scare off monkeys by mimicking their ‘natural enemies’ may work – but not for the reasons it’s supposed to<figure><img src="https://images.theconversation.com/files/546979/original/file-20230907-2965-p3r7t.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3420%2C2258&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rhesus macaques are known for harassing people in cities. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-portrait-beautiful-rhesus-macaque-family-2150489585">Wirestock Creators/Shutterstock</a></span></figcaption></figure><p>The hosts of this year’s G20 summit in New Delhi, India, face a unique challenge: keeping monkeys from interfering with the event. The area’s <a href="https://www.itv.com/news/2023-08-31/monkey-impersonators-to-scare-off-troublesome-primates-at-new-delhi-g20">rhesus macaques</a> are bold and curious, but can be aggressive.</p>
<p>The municipal council’s strategy is to hire humans to imitate <a href="https://www.britannica.com/animal/langur">langur monkeys</a> and scare off the macaques. The langur is <a href="https://wildlifesos.org/rescue/langurs-against-monkeys-a-tale-of-poor-conflict-management/">traditionally believed</a> to frighten macaques as they are supposedly “natural enemies”. It may work, but not for the reasons it’s supposed to. </p>
<p>And the use of professional monkey mimics hints at a much bigger issue: as our cities grow we will only experience more challenges interacting with nature.</p>
<p>On Delhi’s parliamentary estate, near where the summit is being held, macaques are known for <a href="https://www.independent.co.uk/news/world/asia/monkeys-india-delhi-parliament-video-rhesus-macaques-government-offices-a8679151.html">stealing lunches and damaging property</a>. They often bite. In the city of Shimla in the Himalayan foothills <a href="https://www.tribuneindia.com/news/archive/himachal/three-to-four-people-being-bitten-by-monkeys-daily-in-shimla-617216">three to four people were bitten</a> by macaques every day in 2014-2018. </p>
<p>It’s good news for G20 visitors, then, that New Delhi’s municipal council <a href="https://www.aljazeera.com/news/2023/8/31/india-erects-life-size-cutouts-of-langurs-to-deter-monkeys-before-g20">has plans</a> to keep macaques at bay.
India <a href="https://timesofindia.indiatimes.com/city/delhi/monkey-scarers-ape-langurs-sound-not-look/articleshow/39436940.cms">banned the use of langurs</a> for this purpose in 2012 because of concerns about their welfare in captivity, where they were often kept chained. </p>
<p>Instead, for the G20 summit, 40 people have been <a href="https://www.reuters.com/world/india/monkey-business-delhi-gets-cutouts-langurs-ease-menace-during-g20-2023-08-31/">hired as monkey mimics</a>. Their job will include positioning life-size langur cut-outs around key parts of the city and imitating langur calls to scare off the local macaques.</p>
<h2>Why might a monkey-mimic scare a macaque?</h2>
<p>Two animals might be called natural enemies if they <a href="https://www.nature.com/scitable/knowledge/library/species-interactions-and-competition-102131429/">compete</a> for the same foods, space or resources. But <a href="https://www.researchgate.net/publication/283345651_An_instance_of_inter_species_interaction_between_Hanuman_Langur_Semnopithecus_entellus_and_Rhesus_Macaque_Macaca_mulatta">research</a> shows this is unlikely to be the case for langurs and macaques. </p>
<p>Rhesus macaques are <a href="https://www.iucnredlist.org/species/12554/17950825#habitat-ecology">widely distributed</a> from Afghanistan to China. They eat a highly varied diet that includes a lot of fruit, plus bark, seeds, buds and animal foods like fish, shellfish, eggs, honeycomb and insects. </p>
<p>Langurs are <a href="https://pubmed.ncbi.nlm.nih.gov/9210017/">physically larger</a> than rhesus macaques, so might win in a face-off, but are more narrowly distributed. Langurs mainly eat leaves but also consume some fruit, flowers and insects. Their reliance on leaves, however, means that in the wild they would not usually compete with macaques for food. </p>
<p>Macaques and their close relatives thrive in urban environments and rapidly adapt to dealing with people. For example, baboons in Cape Town <a href="https://www.dailymail.co.uk/news/article-2424990/Baboon-steals-groceries-shopper-Cape-Town.html">mug people for groceries</a> while Bali’s long-tailed macaques have <a href="https://www.theguardian.com/science/2021/jan/14/balis-thieving-monkeys-seek-bigger-ransoms-for-high-value-swag-study">learned to barter</a> tourists’ stolen phones for food. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/8q1MyVUze8M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>Langurs also seem to adapt less readily to urban areas than macaques, but can still be remarkably successful in cities. One group in Dakhineswar, for example, now consistently <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2021.649027/full">prefer bread to any plant</a>. </p>
<p>Cities have so much food available that urban macaques and langurs probably don’t need to fight for resources. Their ecological differences in the wild also mean they probably don’t have a long-term history of competition. </p>
<p>This is backed up by evidence of <a href="https://www.researchgate.net/publication/283345651_An_instance_of_inter_species_interaction_between_Hanuman_Langur_Semnopithecus_entellus_and_Rhesus_Macaque_Macaca_mulatta">peaceful, even friendly interactions</a> between langurs and macaques in the wild. Juveniles sometimes play together. The adults are less friendly, but do not seem to object to one another’s presence. This is a far cry from what we’d expect reading about langurs’ supposed aggression towards macaques. </p>
<h2>The heart of the problem</h2>
<p>The ban on the capture of langurs is, in one way, a step forward for animal welfare. It’s good for conservation too as numbers of all seven langur species native to India are in decline. But this New Delhi approach may be bad for macaque welfare. </p>
<p>If langurs are not inherently scary to macaques, why do the authorities think that monkey-mimics’ calls and cut-outs will deter them? The most likely answer is that those calls and langur cut-outs are themselves intimidating. </p>
<p>New Delhi’s monkey mimics <a href="https://www.business-standard.com/article/current-affairs/govt-hires-humans-to-impersonate-langurs-to-scare-away-monkeys-114073101507_1.html">carry sticks</a>. Their langur calls are described as “<a href="https://www.npr.org/sections/parallels/2014/08/05/337973461/india-makes-a-renewed-push-to-crack-down-on-monkey-business">ear-piercing</a>” screeches. Langur noises are already loud, and the mimics may make them louder to maximise their effect.</p>
<p>Taking the job seriously means working to cultivate fear so the effect doesn’t wear off. Being chased by a shouting, stick-wielding human is probably much scarier than seeing a langur. The cut-outs may be still and silent, but are associated with these scary humans, who macaques may see placing the cut-outs. These are probably intimidating as reminders of the monkey-mimics themselves. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Grey female monkey cradles her baby." src="https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546980/original/file-20230907-25-m2cfp1.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">Langurs are supposed to scare off macaques.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/female-gray-langurs-called-hanuman-monkeys-2172877115">Albert Beukhof/Shutterstock</a></span>
</figcaption>
</figure>
<p>Human-wildlife conflict is an almost inevitable consequence of human population growth and the expansion of urban areas. There are often negative effects for everyone. </p>
<p>Even if a macaque troop native to New Delhi was forced into urban life by human expansion, it’s not as if we can assume the humans had somewhere else to go. Urban expansion, poverty and inequality are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/rode.12866">connected in complicated ways</a>, but people are now so <a href="https://www.un.org/en/dayof8billion">numerous</a> that we can’t just stop building cities. </p>
<p>Monkeys harassing visitors to a political summit may seem like a small problem but it’s interlinked with the <a href="https://21stcenturylab.lincoln.ac.uk/ten-grand-challenges/">major challenges of the 21st century</a>: climate change, inequality, sustainability and globalisation. </p>
<p>There are no easy solutions to human-wildlife conflict. You could argue that the New Delhi case is positive because the people involved are looking for a way to manage a conflict that considers the impact on all the species involved.</p>
<p>It is not, however, a perfect approach. It’s a step in the right direction rather than a solution. Each idea that focuses on improving quality of life for both people and animals brings us closer to living together peacefully. </p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&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>Isabelle Catherine Winder 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>Rhesus macaques are known for harassing people in New Delhi, where the G20 summit is being held, so authorities are taking action – but is it the right action?Isabelle Catherine Winder, Senior Lecturer in Zoology, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2094262023-07-13T14:06:55Z2023-07-13T14:06:55ZMale rhesus macaques often have sex with each other – a trait they have inherited in part from their parents<figure><img src="https://images.theconversation.com/files/536818/original/file-20230711-17-aibxh5.jpg?ixlib=rb-1.1.0&rect=941%2C102%2C3853%2C3154&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Male same-sex sexual behaviour was widespread in a population of rhesus macaques.</span> <span class="attribution"><span class="source">Sam Edwards</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Homosexual behaviour is not limited to humans. Biologists have reported homosexual behaviour in many species of wild animal, ranging from <a href="https://doi.org/10.1371/journal.pone.0166024">bats</a> and <a href="https://doi.org/10.1016/j.anbehav.2010.05.009">birds</a> to <a href="https://doi.org/10.1016/j.tree.2009.03.014">dolphins</a> and <a href="https://doi.org/10.1163/1568539X-bja10062">primates</a>. </p>
<p>When animals engage in homosexual behaviour, one might assume that they invest less time and energy on reproduction. This suggests that there may be strong reproductive costs associated with such behaviour, such as having fewer offspring. So it raises the question of how homosexual behaviour manages to evolve and continue to exist within a population.</p>
<p>The underlying presumption is that there is not only a cost associated with engaging in homosexual activity, but also that variation in such behaviour is passed down from one generation to the next. Called heritability, this is essential for any evolution by natural selection to occur. </p>
<p>We set out to investigate these issues by studying 236 male <a href="https://www.britannica.com/animal/rhesus-monkey">rhesus macaques</a> living freely in a colony of 1,700 monkeys on the tropical island of Cayo Santiago, Puerto Rico. We observed these monkeys for three years and <a href="https://doi.org/10.1038/s41559-023-02111-y">found that</a> male same-sex sexual behaviour (SSB) was widespread. In fact, 72% of the males we observed mounted other males, while only 46% mounted females.</p>
<p>Critically, male SSB is not unique to this population of macaques. We saw similar behaviour in wild rhesus macaque populations in northern Thailand. And there have been <a href="https://www.google.com/books/edition/Primate_Behavior/QingBAAAQBAJ?hl=en&gbpv=0">previous reports</a> of SSB in this species from India, too.</p>
<figure class="align-center ">
<img alt="A rhesus macaque colony." src="https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536787/original/file-20230711-30-f7j44b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A rhesus macaque colony in Rajasthan, India.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rhesus-monkey-colony-alwar-rajasthan-india-159063821">Attila JANDI/Shutterstock</a></span>
</figcaption>
</figure>
<h2>From one generation to the next</h2>
<p>We also had access to pedigree records that traced the parentage of each macaque back to 1956. This allowed us to explore the effect of relatedness (heritability) on their behaviour, taking into account other factors that could influence the results, such as age and social group structure.</p>
<p>We found that the heritability of male SSB was 6.4%, meaning genetics do account for a small proportion of SSB – the rest is environmental.</p>
<p>We calculated “evolvability” to be 14.9%, giving the potential rate at which the trait can evolve per generation through natural selection. Evolvability is thought to be a more reliable indicator than heritability of the degree to which genetics can respond to evolutionary pressure, and provides us with further evidence that SSB can evolve through selection.</p>
<p>Our estimates align with what we would expect for a behavioural trait that is probably influenced by multiple genetic factors and environmental effects. They are also consistent with heritability values reported in studies of other social behaviour in primate species, including <a href="https://doi.org/10.1093/evolut/qpad066">social grooming in baboons</a> and <a href="https://doi.org/10.1038/s41437-022-00558-6">social proximity in capuchins</a>. </p>
<p>We also found a genetic correlation between the number of times a male was observed mounting another male and the number of times he was mounted by other males. This suggests that different forms of SSB in these monkeys share a common genetic basis.</p>
<figure class="align-center ">
<img alt="Two grooming chacma baboons on a tree." src="https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536773/original/file-20230711-25-fgafa9.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">Two chacma baboons grooming eachother. Caprivi, Namibia.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/two-grooming-chacma-baboons-papio-ursinus-2250991039">Fotografie-Kuhlmann/Shutterstock</a></span>
</figcaption>
</figure>
<h2>What underpins this behaviour?</h2>
<p><a href="https://doi.org/10.1126/science.aat7693">Previous studies</a> on the heritability of SSB have primarily focused on humans. However, these studies often rely on self-reported data, which can introduce complications. The cultural stigma surrounding homosexuality, for instance, could lead to the underreporting of homosexual activity.</p>
<p>Heritability of SSB has also been found in some invertebrate species, including <a href="https://doi.org/10.1186/s12862-016-0658-4">seed beetles</a> and <a href="https://doi.org/10.1098/rspb.2015.0429">fruit flies</a>. However, the pathways through which SSB develops in these species are thought to be different from those observed in social vertebrates like primates. For example, factors such as <a href="https://doi.org/10.1007/s00265-013-1610-x">imperfect sex recognition</a> are believed to influence the development of SSB in invertebrates.</p>
<p>Demonstrating that SSB is heritable and its potential for evolutionary response to natural selection is an important first step towards understanding the factors that influence variation in this behaviour. </p>
<p>Many evolutionary theories for SSB in animals exist. But they all depend on the behaviour showing a degree of heritability. </p>
<p>One theory suggests that in some species, animals may engage in SSB because it serves a <a href="https://doi.org/10.1016/j.anbehav.2007.02.001">beneficial social function</a>. For example, it may strengthen the bonds between males, ultimately benefiting them during competition for mates and food. </p>
<p>In support of this theory, our research found that male rhesus macaques involved in SSB partnerships were more likely to support each other in conflicts with other individuals. This effect could be a way in which SSB benefits a macaque and its chances of producing offspring, thereby allowing the behaviour and the genes associated with it to persist within a population.</p>
<figure class="align-center ">
<img alt="A group of macaques fighting." src="https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=267&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=267&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=267&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=335&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=335&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536779/original/file-20230711-15-ln4ks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=335&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rhesus macaques involved in SSB partnerships were more likely to support each other in conflicts.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/group-macaques-fighting-1998316622">Di Qin/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Learning from primates</h2>
<p>So what can we learn from these findings about SSB across primate species, including humans?</p>
<p>A <a href="https://doi.org/10.1126/science.aat7693">previous study</a> examining SSB heritability in humans found significant reproductive costs associated with this behaviour. In contrast, we found no such costs in macaques. </p>
<p>This suggests that the costs associated with human SSB might arise from specific social factors unique to humans. However, more research is needed to explore this idea further.</p>
<p>Today, some people still believe that SSB is rare or the product of extreme and unusual environmental conditions, and selectively look to examples in nature to validate their view. Our results may help to challenge these beliefs and combat prejudice against homosexuality and bisexuality. However, society’s moral obligation to strive for more inclusivity and acceptance of different sexual orientations ultimately does not rely on observations from the natural world.</p><img src="https://counter.theconversation.com/content/209426/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jackson Clive received funding for this work from the UK Natural Environment Research Council, the American Institute of Bisexuality and the Genetics Society.</span></em></p><p class="fine-print"><em><span>Ewan Flintham receives funding from the UK Natural Environment Research Council
. </span></em></p><p class="fine-print"><em><span>Vincent Savolainen receives funding from NERC, the American Institute of Bisexuality and the Evolution, Education Trust. </span></em></p>Most of the males in a Puerto Rican monkey colony engaged in homosexual activity, a new study reveals.Jackson Clive, Postdoctoral Researcher, Imperial College LondonEwan Flintham, Postdoctoral Researcher, Université de LausanneVincent Savolainen, Professor of Organismic Biology, Imperial College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2018002023-04-11T16:12:13Z2023-04-11T16:12:13ZGreat apes like to spin themselves dizzy, a lot like children do, research shows<figure><img src="https://images.theconversation.com/files/519625/original/file-20230405-18-3jddjj.jpg?ixlib=rb-1.1.0&rect=9%2C22%2C3015%2C1990&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/orangutan-portrait-young-monkeys-1975040408">Evgeniyqw/Shutterstock</a></span></figcaption></figure><p>Children love to spin. Whether it is by whirling around on their feet, whipping around on a tyre swing, or tumbling down a grassy hill, they revel in the drunken effects of dizziness that follow. As humans mature, they might outgrow spinning on the playground, but find other ways to alter their senses - dancing, skating, roller coasters, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202501/">and for some of them, psychoactive drugs</a>. </p>
<p>It turns out humans are not the only primate with a desire to spin ourselves and stimulate our senses. In a <a href="https://link.springer.com/article/10.1007/s10329-023-01056-x">recent study</a>, my co-author Adriano Lameira and I found some other primates like to do this too. The great apes – which include chimpanzees, bonobos, gorillas, and orangutans, in addition to humans – <a href="https://australian.museum/learn/science/human-evolution/humans-are-apes-great-apes/">have a more complex brain than other primates</a> and share a similar neurophysiology. Our findings suggest that they also share our desire to induce altered states of perception. This may even have played a role in the evolution of the human mind.</p>
<p>In <a href="https://www.youtube.com/watch?v=VNKyG4C2VlA">2011</a>, and then again in <a href="https://www.youtube.com/watch?v=XfS5kBGBh00">2016</a>, a captive gorilla named Zola went viral for his flair for “breakdancing” – the spinning, playful displays that he liked to perform while splashing around in water. These videos made me wonder about the spinning behaviour of apes more generally. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VNKyG4C2VlA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>Spinning has been documented as a part of great apes’ repertoire of <a href="https://link.springer.com/article/10.1007/s10071-017-1096-4">communicative gestures</a>, in previous research. But Zola’s behaviour appeared to be as much about fun as it was about communication. </p>
<p>I scoured YouTube for videos of spinning primates and found <a href="https://evolang.org/jcole2022/proceedings/jcole2022_proceedings.pdf#page=606">hundreds of examples</a> of great apes and other primates spinning themselves around in different ways, from pirouettes to backflips. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Young chimpanzee swinging in tree" src="https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=898&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=898&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=898&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1128&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1128&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519626/original/file-20230405-1625-49lngr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1128&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 apes in the study got dizzy for the fun of it.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-chimpanzee-swinging-tree-264035690">Abeselom Zerit/Shutterstock</a></span>
</figcaption>
</figure>
<p>In our study, my team focused on 40 videos which showed great apes spinning themselves on ropes and vines. We thought ropes might enable the apes to spin at faster speeds and for more rotations than they could with just their bodies. </p>
<p>Our intuition proved right: they often reached and <a href="https://www.youtube.com/watch?v=J19RDBMAOKU">sometimes exceeded speeds</a> of two to three rotations per second. That’s as fast as human spinning experts we compared, which included ballet dancers, circus performers, <a href="https://www.cambridge.org/core/journals/congress-on-research-in-dance/article/abs/ukrainian-hopak-from-dance-for-entertainment-to-martial-art/11FE9632C947D1663532123655CFEBBA">Ukrainian hopak dancers</a> and <a href="https://www.washingtonpost.com/lifestyle/travel/heres-what-you-should-know-before-attending-a-whirling-dervish-ceremony-in-turkey/2019/04/11/1af4bbac-57af-11e9-9136-f8e636f1f6df_story.html">Sufi whirling dervishes</a>. </p>
<h2>Apes still get dizzy</h2>
<p>These professionals train themselves to be <a href="https://academic.oup.com/cercor/article/25/2/554/305011">immune to the sensory effects</a> of extreme spinning. But – as I can attest, having recently tried this in my office (for science) – spinning around at even one rotation per second will make most people dizzy. </p>
<p>The spinning apes in our study appeared to fare no differently. They would often spin for multiple bouts. Three on average, with each bout lasting for about five-and-a-half rotations. Between bouts, the apes would sometimes let go of the rope and stumble around, often falling clumsily to the ground, before jumping back up to do it again. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/J19RDBMAOKU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Many of the apes we observed were in captivity, and in these cases, rope spinning may have helped them overcome boredom. But we also found several instances of young mountain gorillas in the wild spinning on jungle vines during playful social interactions, sometimes even taking turns. They too would spin, stumble around, fall, and get back up to do it again. </p>
<p>Given the close evolutionary relationship between great apes and humans, it is likely the motivation to spin stems from a shared tendency to seek and delight in experiences that stimulate and alter our senses. </p>
<h2>Humans turn to drugs</h2>
<p>Of course, humans sometimes go far beyond spinning to achieve this. The deliberate use of psychotropic drugs, from alcohol and tobacco, to marijuana and LSD, is widespread in cultures across the world. </p>
<p>It often plays an important role in many <a href="https://doi.org/10.15184/aqy.2021.177">social rituals and spiritual ceremonies</a>. For example, in some indigenous cultures of South America, the use of the <em>ayahuasca</em> (a hallucinogenic brew made from local plants) is used by shamans (and others) to connect with ancestors thought to exist in other realms. </p>
<p>Evidence of similar rituals can be <a href="https://www.pnas.org/doi/full/10.1073/pnas.1902174116#">traced back for millennia</a>. Some scientists have <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2021.729425">argued that psychedelics</a> might have been crucial to the evolution of modern human cognition and culture, enhancing our creativity and helping us to forge deeper social connections.</p>
<p>Mushrooms containing <a href="https://en.wikipedia.org/wiki/Psilocybin">psilocybin</a> might have played an especially important role, as they would have been prevalent in many of the habitats of our hominid ancestors. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Young chimpanzee swinging and jumping from a tree" src="https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519628/original/file-20230405-14-g42aaf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hard to deny this young chimpanzee is enjoying twirling around.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-chimpanzee-swinging-jumping-tree-200203994">Abeselom Zerit/Shutterstock</a></span>
</figcaption>
</figure>
<p>Compared to twirling induced dizziness, chemical substances offer a more intense way to alter your state of consciousness. And it may seem a long way from spinning yourself dizzy to having a spiritual epiphany on a psychedelic trip. </p>
<p>Yet, spiritual practices such as those performed by the Sufi dervishes, <a href="https://www.youtube.com/watch?v=lFIQMM8bZQk">who whirl themselves into a meditative trance</a>, demonstrate the potential for spinning to induce a profoundly altered state of mind. Perhaps even gentle spinning helps us to see the world from a different perspective.</p><img src="https://counter.theconversation.com/content/201800/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marcus Perlman 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>Orangutans, gorillas and chimpanzees seem to enjoy the buzz of getting dizzy.Marcus Perlman, Lecturer in English Language and Linguistics, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1968622023-04-06T12:06:48Z2023-04-06T12:06:48ZMacaque monkeys shrink their social networks as they age – research suggests evolutionary roots of a pattern seen in elderly people, too<figure><img src="https://images.theconversation.com/files/517325/original/file-20230324-22-v5nrpg.JPG?ixlib=rb-1.1.0&rect=157%2C0%2C2994%2C2087&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Older monkeys still hang out, just with a smaller circle of intimates.</span> <span class="attribution"><span class="source">Lauren Brent</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>There are many changes that can come with old age – hair turns gray, eyesight isn’t quite what it used to be, mobility often becomes limited. But beyond these physiological changes, people also experience changes to their social world. As we age, <a href="https://doi.org/10.1037/a0028601">our social circles tend to get smaller</a>.</p>
<p>Such declines in social networks have raised concern among scientists who are aware of just how <a href="https://doi.org/10.1126/science.aax9553">important social relationships are to health and well-being</a>. Being socially isolated can harm health as much as <a href="https://doi.org/10.1371/journal.pmed.1000316">obesity, alcoholism or sedentary living</a>.</p>
<p>In the past decade, however, scientists have started to think that the shrinking of social networks with age might not be all bad.</p>
<p>Rather than social declines being driven exclusively by the death of friends or deteriorating health, people might become more selective in their social interactions as they age. After all, many older adults tend to <a href="https://doi.org/10.1037/0882-7974.9.2.315">focus their social effort on family and close friends</a>. This change in social focus might result from older adults’ being <a href="https://doi.org/10.1037/0003-066X.54.3.165">aware of the limited time they have left</a> and prioritizing their most important relationships.</p>
<p>As a <a href="https://erinsiracusa.weebly.com/">behavioral ecologist</a> and <a href="https://smack-lab.com/team/noah-snyder-mackler/">a molecular ecologist</a>, we were interested in understanding the evolutionary roots of these age-based changes in social focus.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lone monkey sits on some branches" src="https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505683/original/file-20230121-20-idfswj.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">An older female macaque sits alone on Cayo Santiago, Puerto Rico.</span>
<span class="attribution"><span class="source">Noah Snyder-Mackler</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>To investigate whether other animals share these patterns of social selectivity with age, we turned to a free-roaming population of over 200 macaques on the island of <a href="https://www.youtube.com/watch?v=5j1ezxH0hAQ">Cayo Santiago</a> in Puerto Rico. In collaboration <a href="http://www.laurenbrent.com/">with</a> <a href="https://www.nyuprimatology.com/">our</a> <a href="https://plattlabs.rocks/our-team/michael-platt">colleagues</a>, we collected eight years of data about how these monkeys interacted with one another as they got older.</p>
<p>We found striking parallels to the patterns of social aging seen in humans, and <a href="https://doi.org/10.1073/pnas.2209180119">our study sheds light on the causes and potential consequences</a> of shrinking social networks with age.</p>
<h2>Picky partner choice</h2>
<p>We focused specifically on female macaques, because they have the most stable long-term relationships in this population. With the help of several dedicated research technicians, we followed these females for up to seven hours a day over the course of eight years. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="dozens of monkeys scattered around a rocky beach with one person standing there" src="https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505684/original/file-20230121-14-iddflb.jpeg?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">Daniel Phillips, a research technician, collects data on macaque social relationships on Cayo Santiago, Puerto Rico.</span>
<span class="attribution"><span class="source">Erin Siracusa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>First, we found that female macaques did indeed spend time with fewer social partners as they got older. Aging macaques sat near fewer partners and also groomed fewer partners. Grooming is an <a href="https://doi.org/10.1007/BF02557701">important bonding behavior</a> in macaques that females do only with their besties. </p>
<p>Importantly, this reduction in females’ social circles was not precipitated by their partners dying or by older monkeys being seen as somehow undesirable and therefore to be avoided. We observed that how often other monkeys sought out older females as social partners did not change with age.</p>
<p>Instead, there seemed to be clear evidence that females were actively reducing the size of their social networks over time. Specifically, as females got older, they initiated interactions with fewer group mates. We observed these declines beginning in females who were in their prime years (around 10 years old) all the way through those who were near the end of their lives (around 28 years old).</p>
<h2>A family matter</h2>
<p>Of course, an important piece of this puzzle is who these female macaques did choose to interact with as they got older. </p>
<p>We found that, similar to humans, aging female macaques focused their time and effort on family members and “friends” with whom they shared a particularly strong and stable bond.</p>
<p>While this narrowing of networks and focus on kith and kin does not necessarily result from macaques’ being aware they are nearing death – scientists aren’t sure if nonhuman animals have an <a href="https://doi.org/10.1098/rstb.2013.0486">awareness of their own mortality</a> – it does suggest that there may be a shared evolutionary reason for social selectivity in humans and other primates.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="two monkeys pick through the fur of a third lying on the ground" src="https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505685/original/file-20230121-31602-irg6sz.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 female macaque grooms her offspring on Cayo Santiagio, Puerto Rico.</span>
<span class="attribution"><span class="source">Lauren Brent</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Why might this be? </p>
<p>One possibility stems from the fact that as humans and other mammals get older they experience <a href="https://doi.org/10.1111/ele.13343">declines in their immune system</a>. We get sick more easily and have a harder time recovering when we do come down with something.</p>
<p>Reducing one’s social circle with age may be an important way to <a href="https://doi.org/10.1016/j.tree.2020.07.004">avoid acquiring a disease or other illness</a>. Such a decrease need not be a deliberate strategy, but could be an unconscious tendency that was selected for over evolutionary time because it enhanced biological fitness in our primate ancestors. As a result, this pattern might persist today, even in humans well beyond their reproductive years. </p>
<h2>A hopeful outlook</h2>
<p>So, what does this all mean? Understanding how people can <a href="https://www.who.int/news-room/fact-sheets/detail/ageing-and-health">live longer and healthier lives is a central priority</a> for health organizations worldwide. Figuring out how to maintain valuable social relationships into old age is likely to play a key role in that endeavor.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="five monkeys relax together; two small ones are nursing" src="https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505686/original/file-20230121-8189-crf3zj.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">An older female macaque spends time with her family on Cayo Santiago, Puerto Rico.</span>
<span class="attribution"><span class="source">Lauren Brent</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The results from this study indicate that the shrinking of networks across the life span is an aging pattern that is not unique to humans but may be present in other primates. </p>
<p>While <a href="https://www.pnas.org/doi/10.1073/pnas.1219686110">loneliness in the elderly</a> is a health concern that should not be ignored, there may be important distinctions between those who are unwillingly isolated as they get older and those who choose to stick to a smaller social circle. In the latter cases, shrinking networks with age may not be all bad.</p>
<p>Instead, there may be important benefits to be gained from being selective in our socializing as we get older, which has allowed this pattern to persist for millennia.</p><img src="https://counter.theconversation.com/content/196862/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erin Siracusa has received or currently receives funding from the American Society of Mammalogists, the Arctic Institute of North America, the Natural Sciences and Engineering Research Council of Canada, the National Institute of Health, and the European Research Council.</span></em></p><p class="fine-print"><em><span>Noah Snyder-Mackler has received or currently receives funding from the National Science Foundation, the National Institutes of Health, the Leakey Foundation, Arizona State University, and the University of Washington.</span></em></p>Many older people tend to trim their social circles and focus their social efforts on family and close friends. New research on our close primate relatives may help explain why.Erin Siracusa, Postdoctoral Research Fellow in Animal Behaviour, University of ExeterNoah Snyder-Mackler, Assistant Professor of Evolution and Medicine, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2005542023-03-02T14:25:20Z2023-03-02T14:25:20ZRoads and power lines put primates in danger: South African data adds to the real picture<figure><img src="https://images.theconversation.com/files/511943/original/file-20230223-703-kx83eg.jpg?ixlib=rb-1.1.0&rect=11%2C17%2C3982%2C2886&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Samango monkey choosing to use a pole bridge instead of a ladder bridge.</span> <span class="attribution"><span class="source">Birthe Linden</span></span></figcaption></figure><p>About 25 million kilometres of new roads are expected to be built around the world by <a href="https://www.nature.com/articles/nature13717">2050</a>. Along with power lines and railways, roads cut through the landscape everywhere, disrupting ecosystems. This linear infrastructure prevents animals from moving safely around their habitat. It also reduces access to the resources they need, like food, sufficient space and mating partners. </p>
<p>This threat to biodiversity is a conservation issue globally, but especially in developing nations, where <a href="https://www.nature.com/articles/nature13717">90%</a> of new road construction is expected. </p>
<p>The African continent is home to unique biodiversity and extraordinary landscapes. Planned <a href="https://au.int/en/videos/20190101/agenda2063-infrastructure-and-energy-initiatives">infrastructure developments</a> will certainly <a href="https://theconversation.com/kenyas-huge-railway-project-is-causing-environmental-damage-heres-how-159813">threaten</a> some of the last, unspoilt wildernesses on the continent.</p>
<p>We’re particularly concerned about the future of primates. The International Union for Conservation of Nature (IUCN) lists <a href="http://www.primate-sg.org/primate_diversity_by_region/">half of the continent’s 107 primate species as threatened</a>.</p>
<p>According to the <a href="https://www.iucnredlist.org/search?query=Primates&searchType=species">IUCN</a> 18% of the world’s primates are directly affected by roads and railroads and 3% by utility and service infrastructure. These figures are based on limited research, though. The true impact is likely to be higher.</p>
<p>South Africa’s case shows why. None of the South African primate species currently have linear infrastructure listed as a threat under the IUCN. But this doesn’t mean they are not negatively affected. It just means that the lists need to be better informed.</p>
<p>South Africa is the only African country that has long-term, country-wide mortality datasets for both <a href="https://ewt.org.za/what-we-do/saving-species/wildlife-and-transport/">wildlife roadkill</a> and <a href="https://ewt.org.za/what-we-do/saving-species/wildlife-and-energy/">wildlife electrocution</a>. It’s collected by patrol staff, scientists and the general public (<a href="https://theconversation.com/tracking-science-a-way-to-include-more-people-in-producing-knowledge-159587">citizen scientists</a>). </p>
<p>Using this data, <a href="https://brill.com/view/journals/ijfp/93/3-6/article-p235_4.xml">we investigated</a> how roads and power lines affect South Africa’s five primate species: the chacma baboon (<em>Papio ursinus</em>), the vervet monkey (<em>Chlorocebus pygerythrus</em>), the samango monkey (<em>Cercopithecus mitis</em>), the lesser bushbaby (<em>Galago moholi</em>) and the greater or thick tailed bushbaby (<em>Otolemur crassicaudatus</em>).</p>
<p>All species were affected, mostly by roads. We found a total of 483 deaths captured in the databases between 1996 and 2021. The number of deaths is likely to be a lot higher, due to under-reporting. Targeted species- and area-specific surveys are needed to refine this dataset. </p>
<p>The more mortality data is available, the better we will understand impacts, know where to focus interventions and inform future infrastructure developments to lessen the human impact on biodiversity.</p>
<p>We recommend that infrastructure like roads and power lines be more prominently recognised as a direct threat when developing Red List assessments.</p>
<h2>Primate deaths</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Furry black body of monkey on the verge with trees on either side of the road" src="https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=344&fit=crop&dpr=1 600w, https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=344&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=344&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=433&fit=crop&dpr=1 754w, https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=433&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/511944/original/file-20230223-24-c9wbuu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=433&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Samango monkey lying dead at the side of a road.</span>
<span class="attribution"><span class="source">Birthe Linden</span></span>
</figcaption>
</figure>
<p>Most of the electrocution data used in our study was accessed from the <a href="https://www.eskom.co.za/">Eskom</a> Central Incident Register.</p>
<p>Roadkill data for our study was available from two sources: the national database from the Endangered Wildlife Trust’s Wildlife and Transport Programme and our own observations. </p>
<p>Since 2011, the Endangered Wildlife Trust has received records from systematic patrols on certain highways and species -and area-specific expert research surveys. Citizen science data comes from all over the country including national and regional roads, with differing speed limits, widths and vehicle usage.</p>
<p>The area surveyed by systematic patrols amounts to 1,370 km, covering 0.2% of the country’s entire road network and 0.9% of the paved road network.</p>
<p>The highest number of deaths recorded was for vervet monkeys. This was to be expected as vervet monkeys have a much wider geographic range in South Africa than both bushbaby species and the samango monkey, so they have a greater chance of encountering roads and power lines. The greater (or thick tailed) bushbaby and the samango monkey are forest associated and forests cover only about 0.1% of South Africa’s land surface area.</p>
<p>Although the total of 483 primate deaths over 25 years may not appear very high, we can assume that many remain undetected. For example scavengers might remove the dead animals, or they could be hidden by dense vegetation on road verges. They could be in remote places, in the case of power lines, or severely injured animals might die later, a distance away from the road. For roads, the actual mortality rate could be <a href="https://we.copernicus.org/articles/3/33/2002/we-3-33-2002.html">12–16 times higher</a> than the detection rate.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/statistical-ecology-can-unlock-the-power-of-biodiversity-data-in-africa-171513">Statistical ecology can unlock the power of biodiversity data in Africa</a>
</strong>
</em>
</p>
<hr>
<h2>Solutions</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person facing away from the camera looks at a monkey walking along a pole in the tree canopy." src="https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/511945/original/file-20230223-703-ly4rn4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Samango monkey using a pole canopy bridge while observer looks on.</span>
<span class="attribution"><span class="source">Horta Lacueva</span></span>
</figcaption>
</figure>
<p>Encouragingly, there is more and more <a href="https://brill.com/display/post/news/special-issue-of-folia-primatologica-highlights-the-importance-of-canopy-bridges-to-habitat-connectivity-globally.xml">research</a> showing that primates, as well as many other tree-dwelling species, accept man-made canopy bridges as a means to cross gaps in their habitat. </p>
<p>In South Africa we conducted an <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320719319172">experiment in the field</a> to test what kind of canopy bridge primates would use to cross gaps between trees. We found that all five South African primate species used the canopy bridges offered to them. The design they preferred was a solid pole bridge, rather than a ladder bridge. </p>
<p>More and more canopy bridges of various kinds are being provided in different countries. But <a href="https://brill.com/view/journals/ijfp/93/3-6/article-p197_1.xml">research</a> shows that Africa is lagging behind other continents in doing this, and there are no canopy bridges in South Africa. We suggest that all infrastructure development projects should try to give attention to maintaining the integrity of landscapes, for example by providing bridges for animals.</p>
<h2>Public participation</h2>
<p>We all need and use linear infrastructure in our day to day lives, so we all carry some level of responsibility. Hence, we encourage people to record wildlife mortalities and submit them to publicly available repositories such as <a href="https://www.inaturalist.org/">iNaturalist</a> or the <a href="https://www.gbif.org/">Global Biodiversity Information Facility</a>. </p>
<p>A new <a href="https://www.mdpi.com/2076-2615/13/10/1692">Global Primate Roadkill Database</a> has been developed by Laura Praill at Oxford Brookes University and colleagues and is <a href="https://gprd.mystrikingly.com/">available to the public</a>.</p>
<p>Public awareness and participation is essential to lessen the human impact on biodiversity.</p><img src="https://counter.theconversation.com/content/200554/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Birthe (Bibi) Linden is affiliated with the SARChI Chair on Biodiversity Value and Change in the Faculty of Science, Engineering and Agriculture at the University of Venda and the Lajuma Resesarch Centre. She receives funding from the South African National Research Foundation (NRF).</span></em></p><p class="fine-print"><em><span>Wendy Collinson is affiliated with The Endangered Wildlife Trust and the South African Research Chair in Biodiversity Value & Change, School of Mathematical and Natural Sciences, University of Venda, Thohoyandou, South Africa. She is also a member of the IUCN: Transport Working Group.</span></em></p>Researchers encourage citizen scientists to contribute to datasets on animal deaths caused by infrastructure. This will inform efforts to reduce the human impact on biodiversity.Birthe (Bibi) Linden, Postdoctoral Researcher (University of Venda) & Associated Researcher (Lajuma Research Centre), University of VendaWendy Collinson, Research Fellow: South African Research Chair in Biodiversity Value & Change, University of VendaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978502023-02-06T12:20:00Z2023-02-06T12:20:00ZThree surprising reasons human actions threaten endangered primates<figure><img src="https://images.theconversation.com/files/506834/original/file-20230127-25-sl362z.jpg?ixlib=rb-1.1.0&rect=9%2C18%2C2994%2C1976&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A baby chimpanzee enjoys his food. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-gourmet-adorable-baby-chimpanzee-enjoying-1986791387">Michaela Pilch/Shutterstock</a></span></figcaption></figure><p>Monkeys, apes and lemurs are cute, familiar and lovable. But an estimated 60% of all primate species are listed as <a href="https://www.science.org/doi/10.1126/sciadv.1600946">vulnerable, threatened or endangered</a>, according to the International Union for Conservation of Nature, a network of environmental organisations. </p>
<p>You’ve probably heard about the main problems, like <a href="https://theconversation.com/deforestation-on-indonesian-island-of-sulawesi-destroys-habitat-of-endemic-primates-147189">deforestation</a> and the loss of habitat. But primates are a diverse group of animals with a wide geographical range, so there are many more subtle ways our actions as humans put these wonderful animals at risk.</p>
<h2>1. Dogs</h2>
<p>Everywhere we go, our best friends are likely to go with us. <a href="https://link.springer.com/book/10.1007/978-3-031-11736-7">Our review</a> shows that dogs are present in many primate habitats. These predators sometimes kill and injure primates, but they also may simply chase and harass them, disrupting their socialising or foraging. </p>
<p>Being on the lookout for harassing dogs is stressful and causes primates to use more energy. Reducing these potentially lethal encounters depends on conservationists communicating with dog owners, <a href="https://link.springer.com/chapter/10.1007/978-3-031-11736-7_5">who often don’t recognise</a> the danger their dogs pose to such wildlife.</p>
<figure class="align-center ">
<img alt="A black and white dog stands over a monkey in the street. The monkey has its mouth open." src="https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506836/original/file-20230127-7614-6vw6f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Ma. Czarita A. Aguja/Shutterstock</span></span>
</figcaption>
</figure>
<p>When diseases jump between animal species, they can cause serious harm to a species that does not have the necessary resistance. Dog diseases such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9179186/">canine heartworm </a>and <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2018.2772">parvovirus</a> can be passed from dogs to primates, and could potentially be fatal. There’s also the possibility that pathogens – viruses, bacteria or parasites – could evolve to spread more easily or become more deadly. </p>
<h2>2. Depictions</h2>
<p>If you live outside a country where primates live, you may never see a live primate outside of a zoo. Nevertheless, your media choices can still affect their conservation. </p>
<p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118487">Researchers have discovered</a> that our choices of what we watch on YouTube, Instagram or TikTok can end up fuelling the use of primates as pets or in entertainment. Primates are cute, and we love to watch videos of them. However, many of these pictures and videos show them in artificial contexts, such as primates wearing clothes or interacting with office equipment.</p>
<p>When people view such content, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0022050">they often say</a> they want a primate as a pet and are less likely to believe that these animals are endangered. </p>
<p>We can help to protect primates by not viewing or sharing videos that show animals in unnatural situations. The <a href="https://human-primate-interactions.org/resources/">responsibility</a> for interacting with primates respectfully is even higher for those who live near primates or those who embark on <a href="https://theconversation.com/five-ways-to-be-a-responsible-wildlife-tourist-118869">wildlife tourism</a>.</p>
<p>People’s activities can affect where primates live, what food they eat, and how they live their lives. Many tourist destinations in these types of locations cater to people’s desire to interact and take pictures with primates by keeping them as pets or encouraging feeding or similar interactions. </p>
<p><a href="https://link.springer.com/book/10.1007/978-3-031-11736-7">Our research found</a> that these practices harm the animals, increase the poaching or the trade of primates, and can lead to dangerous situations for both the primates and people. Photographs that show monkeys posing with humans alarm primatologists because we understand the risks of being bitten or of passing on diseases. But the wider public may be unaware of these dangers.</p>
<h2>3. Disease</h2>
<p>The potential for disease transmission between humans and primates is high, partly because of our closely related biology. When diseases move from animals to humans they are known as “zoonoses”. And when they are transferred from animals to human beings, they are known as “anthroponoses”.</p>
<p>The African apes – chimpanzees, bonobos and gorillas – seem to be particularly <a href="https://www.science.org/content/article/primatologists-work-keep-great-apes-safe-coronavirus">vulnerable to human respiratory infections</a>. Protecting these endangered animals from infectious disease is an important conservation goal.</p>
<figure class="align-center ">
<img alt="A silverback gorilla sits within thick, green vegetation" src="https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506845/original/file-20230127-26-x0cl2i.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">An endangered silverback mountain gorilla.</span>
<span class="attribution"><span class="source">Denys Kutsevalov/Shutterstock</span></span>
</figcaption>
</figure>
<p>The risk of disease transmission between humans and nonhuman primates is worsened by close contact. Some primate species have always lived near people. But as human need for space grows and primate habitats become more fragmented, these encounters become more common. </p>
<p>Primate tourism also brings humans closer to wildlife, with people sometimes even holding the animals or sharing food with them. The <a href="https://theconversation.com/putting-primates-on-screen-is-fuelling-the-illegal-pet-trade-91995">pet trade</a> goes further and brings wild primates into our homes, where animals can contract illness from their owners and vice versa. </p>
<p><a href="https://humanprimateinteractions.files.wordpress.com/2022/10/primate-as-pets.pdf">Preventing the primate pet trade</a> and encouraging safe and respectful interactions with wildlife are vital for both human and nonhuman primate health.</p>
<p>These are only a few examples of the ways humans impact wild primates. And animal biologists are increasingly interested in such human-generated issues for wildlife conservation.</p><img src="https://counter.theconversation.com/content/197850/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tracie McKinney is affiliated with the IUCN SSC Primate Specialist Group's Section for Human-Primate Interactions (SHPI).</span></em></p><p class="fine-print"><em><span>Michelle Rodrigues is affiliated with the IUCN SSC Primate Specialist Group's Section for Human-Primate Interactions (SHPI).</span></em></p><p class="fine-print"><em><span>Sian Waters is affiliated with the IUCN SSC Primate Specialist Group's Section for Human-Primate Interactions (SHPI)</span></em></p>Most of us have heard of the dangers of deforestation but there are other more subtle ways that human beings can endanger monkeys, apes and lemurs.Tracie McKinney, Senior Lecturer in Biological Anthropology, University of South WalesMichelle Rodrigues, Assistant Professor, Marquette UniversitySian Waters, Honorary Research Fellow, Durham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1941932022-12-14T19:03:32Z2022-12-14T19:03:32ZWhy humans walk on two legs: a close look at chimpanzees puts some old theories to the test<figure><img src="https://images.theconversation.com/files/494461/original/file-20221109-11066-rc0uqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Issa chimpanzees live in a woodland dominated environment interspersed with riparian forests, grasslands, and rocky out-crops.</span> <span class="attribution"><span class="source">Photo: R. Drummond-Clarke/GMERC</span></span></figcaption></figure><p>There’s no trait that distinguishes humans from all other mammals more clearly than the way we walk. Human habitual bipedalism – obligatory walking on two legs – has long been a defining trait of our species, as well as our <a href="https://www.pnas.org/doi/epdf/10.1073/pnas.1403659111">ancestors</a> as far back as 4.5 million years ago. </p>
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<p>Science’s growing understanding of chimpanzee <a href="https://www.sciencedirect.com/user/identity/landing?code=BvsF9eoluiU4PM_ggq_BzJQI_X1w3TYEkicwlleS&state=retryCounter%3D0%26csrfToken%3D15935e62-4880-4120-b3d0-6bb49e549aff%26idpPolicy%3Durn%253Acom%253Aelsevier%253Aidp%253Apolicy%253Aproduct%253Ainst_assoc%26returnUrl%3D%252Fscience%252Farticle%252Fpii%252FS0003347217304190%253Fcasa_token%253DqVoj9ufZbcMAAAAA%253AhcJ8zDmjghQ1kChZJabBl7nx3qGIAPvifk0mXaNdWe5bLP9jVeRwW0aYK16PqKUl-lcH9f_tWg%26prompt%3Dnone%26cid%3Darp-2498874e-3b20-4793-977f-25ad0d95aa49">culture</a>, communication and <a href="https://www.tandfonline.com/doi/full/10.1080/03949370.2022.2044390?casa_token=elxIS7F_x4sAAAAA%3AwB4IuVnWfxzrKePJ9cE4QhBImDX7CM_9xbumEWGJ-lS-5GbAKNAh1DC1IXvoFB6k9Te23N1vM1NW">emotion</a> may have blurred the understanding of “distinctly human”, but our obligatory bipedalism has stood the test of time. </p>
<p>Why, when, and where bipedalism evolved remains debated, however. Numerous evolutionary pressures have been proposed. Most are about the economics and <a href="https://www.pnas.org/doi/abs/10.1073/pnas.0703267104">energy use</a> of walking on two legs (bipedalism is far more efficient than quadrupedalism). Other theories describe the advantages of <a href="https://www.cell.com/fulltext/S0960-9822(12)00082-6">carrying objects</a>. Bipedalism frees the hands to do interesting things like make and use tools and reach for fruit. It also enables us to see over tall grass.</p>
<p>But almost all the theories suggest that bipedalism is an adaptation to getting around on land. It’s clear that early bipeds evolved when <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2007.01323.x">savanna grasslands</a> became increasingly common as forests retreated 4-8 million years ago. Walking on two legs made it easier to forage and travel on the ground. </p>
<p>But there’s also evidence that contradicts this idea. Hominin anatomy, palaeo-ecology and the behaviour of some ape species present challenges to the theory. For example, early hominins had a long list of <a href="https://www.science.org/doi/full/10.1126/sciadv.abf2474">adaptations</a> to life in the trees. These included long limbs, mobile shoulders and wrists, and curved fingers. All these features are present in our current tree-dwelling primate cousins. </p>
<p>Studies of what <a href="https://www.sciencedirect.com/science/article/pii/S0047248418302902?casa_token=zpa8_BZQXvAAAAAA:c-tr7PRhAWte_RzlQnyDGdILAd04q0V9ezzraZWCt2-TWYBzxWX8y0SZq3vDgG9goRFENvcjvQ">hominins ate</a> and the animals they lived with (bushbucks, colobus monkeys) also suggest that these hominins did not live in grasslands. Instead, they inhabited mosaic landscapes, consisting most likely of a mixture of riparian forests and woodlands. </p>
<p>Finally, evidence from the only non-African great ape – the orangutan – suggests bipedalism was an <a href="https://www.science.org/doi/10.1126/science.1140799?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">adaptation to living in trees</a>. It helped the apes to negotiate flexible branches high in the tropical rainforests of southeast Asia.</p>
<p>To further test hypotheses about how hominins may have foraged and moved in a mosaic habitat – and whether this habitat pushed them to evolve towards living on the ground and walking on two legs – <a href="http://www.science.org/doi/10.1126/sciadv.add9752">we investigated</a> the behaviour of wild chimpanzees in a savanna mosaic in the Issa valley in Tanzania. </p>
<h2>Issa chimpanzees</h2>
<p>Issa chimpanzees live in an environment dominated by woodland. It is interspersed with grasslands, rocky outcrops and forests alongside streams. We followed chimpanzees for 15 months, collecting data every two minutes on an individual’s positional behaviour, the vegetation type they were in (forest, woodland), and what they were doing (foraging, resting, grooming and so on).<br>
We expected that chimpanzees would spend more time on the ground and standing or moving upright in open vegetation like woodlands where they cannot easily travel via the tree canopy. We thought they would be more terrestrial overall compared with their forest-dwelling cousins in other parts of Africa.</p>
<p><a href="http://www.science.org/doi/10.1126/sciadv.add9752">We found</a> that Issa chimpanzees do indeed spend more time on the ground in woodlands than in forests. But they were not more terrestrial than other (forested) communities. In short, it is not a simple rule of fewer trees leads to more time on the ground. </p>
<p>It’s not clear why Issa chimpanzees spent so little time on the ground. It could be that they spend more time within feeding trees due to <a href="https://www.nature.com/articles/s42003-018-0115-6">tougher foods</a> that may take longer to process than those found in the forests. Alternatively, they could be staying out of the reach of Issa’s many predators, including wild dogs, hyenas, and lions. We don’t yet know what is driving Issa chimpanzees into the trees.</p>
<p>Our findings also suggest a decoupling between terrestial activity and bipedalism. Over 85% of bipedal events were when chimpanzees were in trees (mostly feeding), not on the ground, similar to what was described for orangutans.</p>
<p>Our data from Issa do not support the view that bipedalism evolved as a terrestrial behaviour, especially in more open habitats.</p>
<h2>Why it matters</h2>
<p>Our study represents the first test in a living ape of the long-held hypothesis that cool, dry and open environments during a critical junction in human evolution catalysed the evolution of terrestrial bipedalism.</p>
<p>Issa allows us to study ape-habitat interactions as they might have been millions of years ago. Hominins may not have responded to a mosaic landscape in exactly the same way as today’s chimpanzees do. But the way savanna chimpanzees move around and hold their bodies supports the idea that early hominin bipedalism evolved in the trees, not on the ground.</p><img src="https://counter.theconversation.com/content/194193/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Almost all theories of human bipedalism explain it as a terrestrial adaptation. A new study does not support that view.Fiona Stewart, Lecturer in Wildlife Conservation, Liverpool John Moores UniversityAlexander Piel, Asso. Professor in Anthropology, University College London, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1909442022-09-22T18:45:33Z2022-09-22T18:45:33ZWhen monkeys use the forest as a pharmacy<figure><img src="https://images.theconversation.com/files/485355/original/file-20220919-875-k96p53.jpeg?ixlib=rb-1.1.0&rect=0%2C32%2C5472%2C3604&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A golden-rumped lion tamarin</span> <span class="attribution"><span class="source">Olivier Kaisin</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>Have you ever seen your cat or dog eating grass? They do so because it can help their digestion, and many wild species use natural substances to prevent and control diseases or to repel parasites. This is called “zoopharmacognosy” or, more commonly, animal self-medication. </p>
<p>This practice, which can have prophylactic (intended to prevent disease) or therapeutic (intended to heal it) functions, includes a wide variety of behaviours, such as the consumption of medicinal plants, soil, or the application of substances to the body. For example, many species consume dirt to acquire essential minerals and also facilitate digestion. In mammals, zoopharmacognosy has been observed in elephants, bears, elk and several carnivore species, and it’s especially well known in primates. </p>
<p>At the Laboratory of Primatology of the State University of São Paulo (UNESP) in Brazil, our team studies the behavioural ecology of the black lion tamarin (<em>Leontopithecus chrysopygus</em>), also known as the golden-rumped tamarin. This is a small neotropical primate, endemic to the Brazilian Atlantic forest and currently threatened with extinction.</p>
<p>One part of this project, which is the subject of my PhD, focuses on the study of the physiological and behavioural responses of tamarins to fragmentation and decline in habitat quality.</p>
<h2>An expedition to Brazil</h2>
<p>In the field, we follow several groups of tamarins within fragments of the Atlantic forest to collect behavioural data and faecal samples for subsequent hormonal analysis. Typically, we woke up at dawn and followed the tamarins from the time they left their sleeping site until they returned to sleep, a little before sunset.</p>
<p>During one of these daily studies, we observed them rubbing their bodies on the trunk of a tree covered with resin. At first we thought that the tamarins were marking their territory, a behaviour that is common in this species. But we soon realised that it was something else. In fact, the individuals in the group were collectively rubbing the area of the trunk from which the resin emanated and were also coating their fur with it. Our first instinct was to record the scene and take samples of the bark and resin to identify the essence of the tree.</p>
<p>When we took the bark sample back to the family that was hosting us during our field campaigns, the hostess immediately recognised the peculiar smell of this tree, which the locals call <em>cabreúva</em>. Indeed, the resin produced has a very woody scent with tones of cinnamon, clove, honey and pine. Our botanical expert later confirmed that it was a species of cabreúva, <em>Myroxylon peruiferum</em>, a tree well known in traditional medicine for its antibiotic, anti-inflammatory and anti-parasitic properties.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482488/original/file-20220902-22-ao60pn.jpeg?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 golden-rumped lion tamarin.</span>
<span class="attribution"><span class="source">Olivier Kaisin</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>The use of this tree by the tamarins was quite intriguing, so we decided to place camera-traps at the foot of the cabreúvas to record future visits by the tamarins. We installed them in three different sites in the state of São Paolo: the Morro do Diabo State Park and in two forest fragments, in Guareí and Santa Maria. The camera-trap records surprisingly revealed that many mammals living in the Atlantic forest visited the cabreúvas. In total, 10 different species were observed rubbing or licking the resin exuding from the trunks of these trees. These included several emblematic neotropical mammals such as the ocelot, the collared anteater, the ring-tailed coati, the tayra, the collared peccary and the red daguet.</p>
<p>For many of these species, this was the first time that behaviour similar to self-medication was observed and described. For example, anteaters used their large claws to rip open the bark and stimulate resin secretion before rubbing their bodies against the exposed trunk. Even more surprisingly, peccaries spread resin on each other’s fur in pairs and head to head. In general, the species seemed to specifically visit the tree to acquire the resin and presumably benefit from its many virtues. </p>
<p>While further studies are needed to identify the properties of the resin sought by the animals and thus confirm that this is indeed zoopharmacognosy, the use of this essence in traditional medicine suggests that mammals visit cabreúvas to heal their wounds and repel parasites. For lion tamarins, the use of cabreúva resin could play an important role in the fight against yellow fever, a mosquito-borne disease that decimates primate populations.</p>
<p>Cabreúva could therefore represent a common and universal pharmacy for the residents of the Brazilian Atlantic Forest. <em>Myroxylon peruiferum</em> is likely to be a valuable – and contested – resource that could help the species that use it to maintain their populations by improving their health and increasing their reproductive success. This discovery could have an important conservation implications, as the disappearance of this species from degraded forest fragments could potentially affect the survival of some species.</p><img src="https://counter.theconversation.com/content/190944/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Olivier Kaisin received funding from the Belgian Scientific Research Fund. This study was funded by several Brazilian organisations: the Coordination for the Improvement of Higher Education Personnel, the Brazilian National Council for Scientific and Technological Development and the São Paulo Research Foundation.</span></em></p>Do you know zoopharmacognosy is? Some animals use trees to treat themselves.Olivier Kaisin, PhD Student, Université de LiègeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1882072022-08-31T12:27:02Z2022-08-31T12:27:02ZExpanding Alzheimer’s research with primates could overcome the problem with treatments that show promise in mice but don’t help humans<figure><img src="https://images.theconversation.com/files/481658/original/file-20220829-8371-fvt75z.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rhesus macaques experience an aging process similar to people's.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/rhesus-macaque-royalty-free-image/993621062">Goddard Photography/E+ via Getty Images</a></span></figcaption></figure><p>As of 2022, an estimated <a href="https://doi.org/10.1002/alz.12638">6.5 million Americans</a> have Alzheimer’s disease, an illness that robs people of their memories, independence and personality, causing suffering to both patients and their families. That number may double by 2060. The U.S. has made <a href="https://doi.org/10.1126/science.361.6405.838">considerable investments</a> in Alzheimer’s research, having allocated <a href="https://www.alz.org/news/2022/increase-in-federal-alzheimers-and-dementia-resear">US$3.5 billion in federal funding</a> this year. </p>
<p>Why, then, are researchers no closer to a cure today than they were 30 years ago? </p>
<p>Back in 1995, researchers created the <a href="https://doi.org/10.1038/373523a0">first transgenic mouse model</a> of Alzheimer’s disease, which involved genetically modifying mice to carry a gene associated with early-onset Alzheimer’s. Myriad studies have since focused on mouse models that accumulate <a href="https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease">abnormal proteins</a> in their brains, a hallmark of the disease. Although these studies made great strides in understanding specific mechanisms involved in the disease, they have <a href="https://doi.org/10.1002/trc2.12114">failed to translate</a> into effective treatments.</p>
<p>As <a href="https://scholar.google.com/citations?user=LWCllSsAAAAJ">research</a> <a href="https://scholar.google.com/citations?hl=en&user=0tW5idcAAAAJ">scientists</a> <a href="https://psych.wisc.edu/staff/bennett-allyson/">working</a> with nonhuman primates, we believe that part of the problem is that mice don’t reflect the full spectrum of Alzheimer’s disease. A more complementary animal model, however, could help researchers better translate the results from animal studies to humans. </p>
<h2>Why animal models?</h2>
<p>A critical aspect of understanding what goes awry in Alzheimer’s disease is the relationship between brain and behavior. Researchers rely heavily on animal models to do these types of studies because <a href="https://grants.nih.gov/grants/policy/air/why.htm">ethical and practical issues</a> make them impossible to conduct in people.</p>
<p>In recent years, researchers have developed <a href="https://doi.org/10.15252/embj.2021110002">alternative methods</a> to study Alzheimer’s, such as computer models and cell cultures. Although these options show promise for advancing Alzheimer’s research, they don’t supersede the need for animal models because of important limitations.</p>
<p>One is their inability to replicate the complexity of the human brain. The human brain has an estimated <a href="https://doi.org/10.1002/cne.21974">86 billion neurons</a> that perform highly complex computations. While computer models can simulate the workings of specific neural circuits, they are unable to fully capture these complex interactions and work best when used <a href="https://doi.org/10.1016/j.neuron.2021.07.015">in concert with animal models</a>.</p>
<p>Similarly, cell cultures and brain organoids – miniature brains derived from human stem cells – are <a href="https://doi.org/10.3389/fphar.2020.00396">unable to adequately mimic</a> the aging process and all the ways the components of the human body interact with one another.</p>
<p>As a result of these limitations, researchers turn to animal models that better reflect human biology and disease processes.</p>
<h2>The problem with mice</h2>
<p>According to the National Association for Biomedical Research, approximately <a href="https://www.science.org/content/article/how-many-mice-and-rats-are-used-us-labs-controversial-study-says-more-100-million">95% of lab research conducted in animals in the U.S.</a> is done in mice and rats. Alzheimer’s is no exception: For more than 25 years, research on Alzheimer’s has <a href="https://doi.org/10.1002/cpns.81">focused on using transgenic mice</a> to better understand the biological changes associated with the disease.</p>
<p>Because mice do not naturally get Alzheimer’s, they are genetically engineered to develop <a href="https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease">abnormal proteins</a> known as amyloid plaques and neurofibrillary tau tangles to mimic Alzheimer’s in their brains. These protein accumulations impair brain function and are associated with memory impairment. While studies on <a href="https://doi.org/10.1038/35050110">treatments that remove these proteins</a> have been able to improve cognition in mice, similar interventions have failed in people.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four white mice in a cage" src="https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481630/original/file-20220829-8838-qz7uav.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">Many Alzheimer’s studies have been conducted in transgenic mice.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/white-research-mice-royalty-free-image/170617385">filo/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>This highlights the challenge of <a href="https://doi.org/10.1002/trc2.12114">translating animal research</a> in the lab to people in the clinic. Mouse studies often mirror only a single aspect of the disease that may not be directly relevant to people. For example, most transgenic mouse models focus on amyloid protein buildup while <a href="https://mitpress.mit.edu/9780262546010/how-not-to-study-a-disease/">neglecting other crucial aspects</a> of the disease, such as overall neurodegeneration. Such limitations have led some scientists to <a href="https://doi.org/10.3390/ijms222313168">question the value of using mouse models for Alzheimer’s research</a>. </p>
<p>It is important to recognize, however, that scientific knowledge often advances in <a href="https://www.statnews.com/2015/12/02/science-groundbreaking/">incremental steps</a> through the collective results of many studies using different methods and models. Rodent studies provide the necessary foundation for animal models that better mimic the full scope of Alzheimer’s – such as nonhuman primates.</p>
<h2>Nonhuman primates offer a closer model</h2>
<p>The specific features of a species – including brain structure, cognitive ability, life span and the extent to which they show the hallmarks of Alzheimer’s – determine how suitable it is for specific research questions. Based on these factors, we believe that nonhuman primates are particularly well suited for Alzheimer’s research.</p>
<p><a href="https://primate.wisc.edu/primate-info-net/pin-factsheets/">Primates</a> are a diverse group of mammals that includes humans, apes, monkeys and prosimians. Nonhuman primates are particularly valuable for understanding <a href="https://doi.org/10.1002/ajp.23309">human aging</a> and <a href="https://doi.org/10.1073/pnas.1912954116">Alzheimer’s disease</a> because their genetic makeup, brain, behavior, physiology and aging process closely resemble those of people. Aging monkeys experience cognitive, physical and sensory decline as well as a variety of illnesses, such as cancer and cardiovascular disease, much like aging people. Perhaps most critical for Alzheimer’s research, nonhuman primates live much longer than rodents and can <a href="https://doi.org/10.1002/ajp.23299">naturally develop some of the hallmarks associated with Alzheimer’s</a> as they get older. </p>
<p>Using nonhuman primates in research <a href="https://www.nature.com/articles/d41586-021-01894-z">faces some challenges</a>. Compared to mice, nonhuman primates are more expensive to house and feed, and face a growing shortage in research facilities. Nonhuman primates are also prime targets for activists seeking to stop the use of animals in research. Yet, in light of ongoing failures with rodent models, nonhuman primates could significantly help scientists better understand and treat Alzheimer’s. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientist looking at brain MRIs on multiple computer screens" src="https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481632/original/file-20220829-8843-ucjkc0.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">Animal models pave the way for clinical research in humans.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/female-radiologist-analysing-the-mri-image-of-the-royalty-free-image/1326240246">simonkr/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>Scientists study Alzheimer’s in nonhuman primates in a number of ways.</p>
<p>In one approach, researchers examine species with short life spans, such as <a href="https://doi.org/10.1002/ajp.23337">gray mouse lemurs</a> or <a href="https://doi.org/10.1002/ajp.23271">common marmosets</a>, to measure how brain and behavior naturally change with age and identify potential predictors of disease. Other researchers may instead accelerate the disease process by <a href="https://doi.org/10.1002/ajp.23289">inducing plaque</a> or <a href="https://doi.org/10.1002/alz.12318">tangle formation</a> in the brains of longer-lived species, like rhesus macaques. These approaches yield studies that are particularly promising for testing treatments in a short time frame.</p>
<p>A third approach takes advantage of recent advances in genomics to study marmosets <a href="https://doi.org/10.1002/alz.049952">born with genetic mutations</a> involved in Alzheimer’s. This method provides the opportunity to test preventive treatments during early life, well before any sign of the disease appears. </p>
<p>Lastly, <a href="https://doi.org/10.1002/ajp.23254">comparing Alzheimer-like patterns across primate species</a> may help reveal critical risk factors for developing the disease, which could be reduced to promote healthy aging.</p>
<p>We believe that research in nonhuman primates, when conducted with the highest <a href="https://doi.org/10.1016/j.neuroimage.2020.117700">ethical standards</a>, provides the best chance to understand how and why Alzheimer’s disease progresses, and to design treatments that are safe and effective in people.</p><img src="https://counter.theconversation.com/content/188207/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Agnès Lacreuse receives funding from NIH, serves on the American Psychological Association Committee for Animal Research and Ethics and volunteers for Speaking of Research</span></em></p><p class="fine-print"><em><span>Allyson Bennett serves on the Board of Directors for Public Responsibility for Medicine & Research and volunteers for Speaking of Research.
</span></em></p><p class="fine-print"><em><span>Amanda M. Dettmer volunteers for Speaking of Research.</span></em></p>Nonhuman primates like rhesus monkeys share certain characteristics with people that may make them better study subjects than mice for research on neurodegenerative diseases.Agnès Lacreuse, Professor of Behavioral Neuroscience, UMass AmherstAllyson J. Bennett, Professor of Psychology, University of Wisconsin-MadisonAmanda M. Dettmer, Associate Research Scientist, Yale UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1811282022-04-11T21:10:11Z2022-04-11T21:10:11ZMonkeys can sense their own heartbeats, an ability tied to mental health, consciousness and memory in humans<figure><img src="https://images.theconversation.com/files/457499/original/file-20220411-16-s3gwnp.jpg?ixlib=rb-1.1.0&rect=17%2C31%2C1479%2C1059&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New research indicates that rhesus monkeys show interoception – the ability to sense physiological processes like their own heartbeats. </span> <span class="attribution"><span class="source">Matthew Verdolivo/UC Davis IET Academic Technology Services</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>Rhesus monkeys have a <a href="https://doi.org/10.1073/pnas.2119868119">sense of when their own hearts are beating</a>, according to new research we conducted.</p>
<p>Sensing one’s own physiological states – like your heartbeat, breathing or blushing cheeks – is called <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/interoception">interoception</a>. Some previous research has shown that animals can be <a href="https://doi.org/10.1016/j.cub.2021.07.011">trained to do tasks that demonstrate this ability</a>. Decades ago, a team of scientists showed rhesus monkeys could <a href="https://doi.org/10.1037/h0030217">be trained to increase and decrease their heart rates</a>. But an open question has been whether monkeys have an unlearned ability to sense their bodily signals rather than being taught to do so.</p>
<p>Both human babies and monkeys look at things that are unexpected or novel for longer amounts of time than they look at things that they expect or are used to seeing. We used a task that relies on this behavior – originally developed to <a href="https://doi.org/10.7554/eLife.25318">test whether human infants can sense their own heartbeats</a> – to learn whether monkeys also have this ability.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Pke81XnMmsQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Monkeys were shown videos of a bouncing cloud or star that was either in sync or out of sync with their own heartbeats. The moving red dot represents where the monkeys were looking. Credit: Joey Charbonneau.</span></figcaption>
</figure>
<p>We first got our monkeys to sit in chairs in front of a computer screen and hooked them up to electrocardiograms to monitor their heartbeats. Then we played videos of either a yellow or green cloud bouncing up and down accompanied by beeping sounds. Sometimes we would sync the bouncing and beeping to match the monkey’s heartbeat, and at other times they were out of sync.</p>
<p>We then used eye trackers to measure how long the monkeys looked at the images. If the monkeys had a sense of their own heartbeats, they would find the in-sync bouncing less interesting and novel than the out-of-sync bouncing and so would spend more time looking at the out-of-sync image.</p>
<p>We tested four monkeys and, <a href="https://doi.org/10.7554/eLife.25318">just like human babies</a>, they looked at the shapes that bounced and sounded out of sync with their heartbeats <a href="https://doi.org/10.1073/pnas.2119868119">for significantly longer</a> – nearly three-quarters of a second – than the in-sync images. Additionally, the extent to which our monkeys paid more attention to out-of-sync shapes than in-sync shapes was very close to the difference in human babies. These findings strongly suggest that monkeys have an innate sense of their own heartbeats.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two small brown monkeys playing in grass." src="https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/457497/original/file-20220411-10836-n5zz32.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">In humans, the ability to sense one’s own physiological functions is tied to consciousness, memory and a number of mental health disorders. Showing this skill in monkeys opens up many research opportunities.</span>
<span class="attribution"><span class="source">Kathy West/CNPRC</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why it matters</h2>
<p>Heartbeat detection tests are the most commonly used to evaluate how aware of bodily signals people are. </p>
<p>In humans, this skill is thought to be central to <a href="https://doi.org/10.1037/0022-3514.87.5.684">emotional experiences</a>, having a <a href="https://doi.org/10.1016/j.tins.2020.09.008">sense of self</a>, <a href="https://doi.org/10.1098/rstb.2016.0005">memory</a>, <a href="https://doi.org/10.1016/j.concog.2016.08.015">knowledge of one’s own cognition</a> and even <a href="http://dx.doi.org/10.1038/nrn2555">consciousness</a>. Abnormally low or high interoception is related to disorders like <a href="https://doi.org/10.1016/j.cpr.2009.08.008">anxiety</a> and <a href="https://doi.org/10.1002/da.20504">depression</a>.</p>
<p>Our work establishes that monkeys and people have a similar sense of their heartbeats and establishes a method for testing this ability across species.</p>
<h2>What’s next</h2>
<p>People are well aware of many subtle physiological functions, not just their own heartbeats. But while some people have a very sharp interoceptive ability, <a href="https://doi.org/10.1080/026999300378905">a lot of humans are really bad</a> at tasks like the one in the study. Next, our team plans to test whether – like people – some monkeys are better than others at sensing their own heartbeats and whether this <a href="https://doi.org/10.1016/j.copsyc.2017.04.020">translates to other psychological features</a>.</p>
<p>Finally, with monkeys, researchers can track animals from womb to tomb, have exquisite experimental control and can carry out detailed anatomical evaluations. This access may allow researchers to determine how interoceptive capacity develops, what features of the social and physical environment shape it and what neural systems underlie it. </p>
<p>Establishing this knowledge could further research into the causes behind many <a href="https://doi.org/10.1016/j.tins.2020.09.009">health challenges</a> caused when interoception goes awry – including <a href="https://doi.org/10.1016/j.bpsc.2017.12.004">mental health disorders</a>, <a href="https://doi.org/10.1098/rstb.2016.0006">neurodegenerative disorders</a> and <a href="https://doi.org/10.1037/emo0000699">aging</a>. </p>
<p>[<em>Climate change, AI, vaccines, black holes and much more.</em> <a href="https://memberservices.theconversation.com/newsletters/?nl=science&source=inline-science-various">Get The Conversation’s best science and health coverage</a>.]</p><img src="https://counter.theconversation.com/content/181128/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Researchers used a test designed for babies to show that rhesus monkeys can sense their own heartbeats. The finding opens up important paths of research into consciousness and mental health issues.Joey Charbonneau, PhD Student in Neuroscience, University of California, DavisEliza Bliss-Moreau, Associate Professor of Psychology, University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1758962022-04-11T15:17:56Z2022-04-11T15:17:56ZAllow me to introduce myself: Squirrels use rattle calls to identify themselves<figure><img src="https://images.theconversation.com/files/457413/original/file-20220411-16-h30zck.jpg?ixlib=rb-1.1.0&rect=21%2C0%2C4655%2C3120&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Squirrel rattle calls may be a form of announcing their presence.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>As a scientist who studies squirrel behaviour, one of the most common questions I am asked is: “How do I get them out of my yard?”</p>
<p>It’s not as easy being a squirrel as you might think. They live a <a href="https://doi.org/10.1139/z95-133">relatively solitary life</a> guarding hard-won food stores to survive the tough winters here in Canada. The behaviour that my students and I are most interested in is how these squirrels use sounds, or what we refer to as vocal communication, to help them make it through this tough life.</p>
<h2>Solitary creatures</h2>
<p>The North American red squirrel lives a somewhat solitary life. They spend most of their days in a 50-100 metre territory foraging for pine cones and other food sources like berries and mushrooms. </p>
<p>Individuals spend time gathering cones throughout the summer and fall months, storing them in a central location called a midden. They can be rather protective of these middens, as squirrels are known to <a href="https://doi.org/10.1644/1545-1542(2005)086%3C0108:FPILRS%3E2.0.CO;2">steal a great deal from each other</a>. In fact, a squirrel can steal up to 90 per cent of its stores from neighbouring squirrels. </p>
<p>These little thieves run back and forth moving and stealing cones to survive the tough Canadian winters. While they are stealing and storing, <a href="https://www.jstor.org/stable/4534898">squirrels often produce a loud call</a>, termed a rattle. I am keenly interested in this call — my students and I watch and record squirrels to understand what these rattles might be communicating. </p>
<p>Historically it was assumed that this rattle call was produced to make sure that squirrels knew to stay out of each other’s territories — in a sense, a warning that if you enter you may encounter some aggression from the squirrel that lives there. My research has been exploring <a href="https://shannonmdigweed.weebly.com/squirrel-speak-and-pika-puns">a slightly different view of this call</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IMOQv1QHxSQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Recordings of various red squirrel vocal communications.</span></figcaption>
</figure>
<h2>Neighbours and strangers</h2>
<p>It is possible that the call still warns other squirrels to stay out, but its <a href="https://doi.org/10.1093/czoolo/58.5.758">primary function is to identify the caller to all those who are listening</a>. As a squirrel moves through its own territory, and the territories of its neighbours, they produce intermittent rattle calls. These calls are <a href="https://www.jstor.org/stable/20799540">an announcement of who and where that squirrel is</a>. Listeners then know where their various neighbours are throughout the day. This knowledge can help mitigate costly aggressive interactions, chases and fights. </p>
<p>In addition, by communicating who is calling, the rattle can signal to listeners who is more likely to steal from you and <a href="https://doi.org/10.1016/j.anbehav.2017.08.024">thus a more threatening neighbour</a>. Some neighbours may be more likely to steal from you than others. </p>
<p>In behavioural ecology, this is referred to as <a href="https://doi.org/10.1006/anbe.1994.1047">the “dear enemy” effect</a>, and supposes that in maintaining a territory it is useful to know the relative threat posed by your neighbours versus the threat posed by strangers. In most cases, a known neighbour is far less of a threat than a stranger. </p>
<p>With red squirrels, it has been shown that <a href="https://doi.org/10.1016/j.anbehav.2017.08.024">different neighbours do have different levels of threat</a>. As a result, knowing who your neighbour is by their rattle call reveals the relative threat they represent and therefore the necessary response.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4684%2C3113&q=45&auto=format&w=1000&fit=clip"><img alt="a young red squirrel carries a pine cone" src="https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4684%2C3113&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/457043/original/file-20220408-11-ggugy7.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">Squirrels lead solitary lives.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Social calls</h2>
<p>Self-announcement or self-identification is a common vocal behaviour across many different species. Several marine mammal species, <a href="https://doi.org/10.1073/pnas.0509918103">such as dolphins</a> <a href="https://doi.org/10.1016/j.beproc.2008.04.007">and seals</a>, also produce calls that contain information about who is calling. They are used to identify social companions and offspring. </p>
<p>Several species of primates also have calls that contain information about who is calling. Again, these are often used in social interactions to help mitigate aggression during foraging — <a href="https://doi.org/10.1006/anbe.1998.1031">baboons</a> and <a href="https://doi.org/10.1002/ajp.20398">capuchin monkeys</a>, for example. So it’s not unusual that a species like the red squirrel would also have information about who is calling to help them with difficult territory interactions. </p>
<p>My students and I have found that squirrels produce these calls throughout their territory as well as in the territory of close neighbours. By conducting experiments on when and where the squirrels produce the rattle call, we hope to show that the occurrence of this call is about announcing who and where you are, and not strictly about getting others out of your territory.</p><img src="https://counter.theconversation.com/content/175896/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shannon M. Digweed 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>North American red squirrels produce a range of sounds, but their distinctive rattle call may have more to do with identifying themselves than warning off other squirrels.Shannon M. Digweed, Associate professor, Psychology and Biological Sciences, MacEwan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1777212022-03-15T12:15:32Z2022-03-15T12:15:32ZThe Ebola virus can ‘hide out’ in the brain after treatment and cause recurrent infections<figure><img src="https://images.theconversation.com/files/452000/original/file-20220314-13-5nsas.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1536&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This image shows Ebola virus particles (red) budding from the surface of kidney cell (blue).</span> <span class="attribution"><a class="source" href="https://flic.kr/p/oq68Cn">National Institute of Allergy and Infectious Diseases/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>The Ebola virus can hide in the brains of monkeys that have recovered after medical treatment without causing symptoms and lead to recurrent infections, according to a study by a <a href="https://www.researchgate.net/profile/Xiankun-Zeng">team I led</a> that was published in the journal <a href="https://doi.org/10.1126/scitranslmed.abi5229">Science Translational Medicine</a>.</p>
<p><a href="https://www.cdc.gov/vhf/ebola/index.html">Ebola is one of the deadliest</a> infectious disease threats known to humankind, with an <a href="https://www.afro.who.int/health-topics/ebola-virus-disease">average fatality rate of about 50%</a>. Ebola is known for a high level of <a href="https://doi.org/10.1038/nmicrobiol.2017.124">viral persistence</a>, meaning the virus remains lurking in the body even after a patient has recovered. But where this hiding place is remains largely unknown.</p>
<p>In 2021, there were <a href="https://www.cdc.gov/vhf/ebola/outbreaks/index-2018.html">three Ebola outbreaks in Africa</a>, all linked to previously infected survivors. Ebola also reemerged in <a href="https://doi.org/10.1038/s41586-021-03901-9">Guinea</a> that same year, linked to a survivor of the 2013-2016 Ebola outbreak.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A laboratory technician in full Personal protective equipment pipettes samples under a lab hood." src="https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/452004/original/file-20220314-131639-4tbiwk.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The researchers conducted their study in a Biosafety Level 4 lab, the highest level of biocontainment required to safely study hazardous pathogens like Ebola.</span>
<span class="attribution"><span class="source">John W. Braun, USAMRIID</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>We wanted to better understand where the Ebola virus “hides” in the body of survivors and what triggers recurrent infections. So we examined 36 rhesus monkeys that had been treated for Ebola with <a href="https://www.uptodate.com/contents/overview-of-therapeutic-monoclonal-antibodies">monoclonal antibody therapy</a>, a type of treatment that helps the immune system mount an attack against an infection. These monkeys were deemed fully recovered with no symptoms of infection or detectable virus in their blood. </p>
<p>When we looked more closely at the tissues of different organs under a microscope, however, we found that about 20% of recovered monkeys still had visible Ebola virus located exclusively in the <a href="https://www.ncbi.nlm.nih.gov/books/NBK11083/">ventricular system</a> of the brain. This brain region produces, circulates and stores <a href="https://medlineplus.gov/lab-tests/cerebrospinal-fluid-csf-analysis/">cerebrospinal fluid</a>, which protects, supplies nutrients to and removes waste products from the brain.</p>
<p>Importantly, despite being asymptomatic at the start of our study, two of the monkeys we observed developed Ebola symptoms before dying at 30 and 39 days after their initial infection, respectively. Our findings suggest that the Ebola virus can hide dormant in the brains of survivors even after treatment, and the virus can reactivate and cause fatal infections later on.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Ventricular system of rhesus monkey that survived Ebola virus infection, with brown stains indicating viral persistence lining the edges" src="https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=379&fit=crop&dpr=1 754w, https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=379&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/452005/original/file-20220314-101106-3uxlee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=379&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This image shows the brain ventricular system of a rhesus monkey that survived Ebola virus infection, where brown indicates viral persistence.</span>
<span class="attribution"><span class="source">Kevin Zeng</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<h2>Why it matters</h2>
<p>Treatment with monoclonal antibodies is the current <a href="https://www.statnews.com/2020/10/15/thank-this-ebola-fighting-african-doctor-muyembe-tamfum-for-monoclonal-antibody-treatments/">standard of care for Ebola</a>. But recurrent infections can occur even after apparently successful treatment, and patients can inadvertently transmit the virus and cause new outbreaks.</p>
<p>Our study underscores the importance of careful long-term medical follow-up of successfully treated Ebola survivors to counter the individual and public health cost of recurrent disease. This follow-up, however, will need to be conducted in a way that does not further <a href="https://longreads.trust.org/item/Ebola-survivors-DRC-combat-stigma-misinformation">stigmatize survivors of the disease</a>.</p>
<h2>What still isn’t known</h2>
<p>We still don’t know why the Ebola virus persists in the brain and causes recurrent infections. It is also unclear whether this persistence might be related to monoclonal antibody treatments, and whether other types of therapies, such as antivirals, might produce a different effect. Researchers are still looking into what triggers relapses and whether there might be other parts of the body that may act as reservoirs.</p>
<h2>What’s next</h2>
<p>Our work highlights the need to more deeply investigate why the Ebola virus persists in the brain. Because the brain is <a href="https://doi.org/10.4161/mabs.3.2.14239">less accessible</a> to monoclonal antibodies, treatments <a href="https://doi.org/10.1016/S1473-3099(20)30282-6">combining both monoclonal antibodies and antiviral drugs</a> may help prevent and clear persistent Ebola infection and related disease in the brain. Analyzing viral persistence at the <a href="https://doi.org/10.1038/s41579-020-0354-7">molecular level</a> may provide more insight.</p>
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<p class="fine-print"><em><span>Kevin Zeng does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Although treatments for Ebola have helped many people overcome this deadly disease, the virus can persist in the brain and cause a lethal relapse.Kevin Zeng, Principal Investigator of Infectious Diseases, U.S. Army Medical Research Institute of Infectious DiseasesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1782462022-03-04T12:14:09Z2022-03-04T12:14:09ZMonkey teeth are shedding new light on how early humans used tools<p>The macaques of Japan’s Koshima Island are a clever bunch. Well known for performing some <a href="https://link.springer.com/article/10.1007/s10329-017-0642-7">remarkably complex tasks</a>, such as washing sweet potatoes and filtering wheat from sand in the seawater, they’ve even been spotted catching <a href="https://www.karger.com/Article/Abstract/156391">live octopuses from the sea</a>.</p>
<p>During continuous observations the macaques’ unique skills were seen rapidly spreading through the population and provided some of the first evidence of local habits in animals. </p>
<p>I recently visited the Primate Research Institute at Kyoto University to study the teeth remains of macaques who had died naturally on Koshima Island, one of the longest running <a href="https://www.wrc.kyoto-u.ac.jp/koshima_st/monkey">primatological field sites</a> in the world. </p>
<p>It was part of a project to create a database of tooth wear and dental disease in wild primates – but I very quickly noticed something extremely unexpected. All the deceased macaques had identical – and very unusual – tooth wear for a primate. And not only that, it seemed remarkably similar to the tooth wear commonly found in hominin (humans and our closely related ancestors) fossil samples. I knew I had to investigate further.</p>
<p>Through collaborations with local primatologists, and experts in studying microscopic features on tooth surfaces, we studied the tooth remains of 32 individuals in more detail, recording the overall tooth wear, fractures and pathologies. This allowed us to directly compare the features on the tooth’s surface with <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/oa.2601">published examples</a> in hominin fossils.</p>
<h2>Surprising toothy similarities</h2>
<p>“Toothpick” grooves on back teeth and large vertical scratches on front teeth are thought to be unique to hominins, and most likely caused by <a href="https://link.springer.com/article/10.1007/s00784-010-0447-1">distinctive tool use</a>. The markings are used as evidence for the earliest forms of cultural habits identified during human evolution. </p>
<p>But as my colleagues and I found these same types of <a href="https://onlinelibrary.wiley.com/doi/10.1002/ajpa.24500">unusual tooth wear</a> in the preserved teeth of the deceased wild Koshima macaques, we set out to try to explain the similarities using a combination of extensive literature and ongoing field observations.</p>
<p>In fossil hominin samples, the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0305440304000214">large scratches</a> on front teeth are typically considered to be caused by a type of behaviour called “stuff and cut” in which an item, such as an animal hide, is held between the front teeth and a stone tool used to slice portions off.</p>
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Read more:
<a href="https://theconversation.com/the-macaque-monkeys-of-mauritius-an-invasive-alien-species-and-a-major-export-for-research-176569">The macaque monkeys of Mauritius: an invasive alien species, and a major export for research</a>
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<p>Accidental contact of the stone tool with the outside of the front teeth causes the marks, and it’s suggested that by studying the orientation and concentration of scratches in different areas of these teeth, insight into <a href="https://www.sciencedirect.com/science/article/abs/pii/S1090513809000221">right or left handedness</a> can be gleaned. </p>
<p>Similarly, because <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23166">“toothpick” grooves</a> commonly form between back teeth, and long thin parallel scratches are often found within these grooves, it has long been considered that these grooves must be caused by a tool being placed into the gap between teeth and repeatedly moved back and forward to remove food debris or alleviate discomfort (hence the name toothpick grooves).</p>
<p>But there is no evidence for these types of tool use in Koshima Island macaques, or indeed any behaviour that could be considered habitual tool use. Instead this wear is likely caused by eating shellfish and accidentally chewing and consuming sand. The macaques were frequently observed picking up food from sandy beaches – and despite their attempts to wash the sand off, some does still get chewed as there is sand in their faeces.</p>
<p>Shellfish are also regularly eaten, and the macaques use their front teeth to both dislodge them from rocks and to scoop out the contents. These behaviours likely cause this extreme wear, due to the sand, hard shells and rock coming directly into contact with different tooth surfaces on a regular basis. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/weve-proved-that-wild-primates-suffer-from-tooth-decay-and-chimps-are-among-the-worst-173385">We've proved that wild primates suffer from tooth decay – and chimps are among the worst</a>
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<p>It is easy to imagine how large parallel scratches could form when biting down on foods covered in sand, or when attempting to dislodge and consume shellfish with no tools.</p>
<p>Why the root grooves and markings within the grooves should form on back teeth when sand or grit is chewed needs further research, but is probably due to small hard particles passing over these surfaces during the mastication cycle and during swallowing.</p>
<h2>Implications for human evolution</h2>
<p>So, it seems that normal chewing and food processing can cause these sorts of wear patterns without the need to infer complex and habitual tool use.</p>
<p>And as there are even more dental similarities between fossil hominin samples and this macaque group at the microscopic level – as well as high rates of tooth chipping, extreme overall tooth wear and the bevelled appearance of front teeth – it has to be considered that there is a common cause that is nothing to do with tool use at all. </p>
<p>Of course, it is the case that humans have been using <a href="https://www.sciencedirect.com/science/article/abs/pii/S0047248421000282">tools for a long time</a>, evident by the substantial number of stone tools found throughout human evolution. But this does not mean that they were responsible for the unusual wear found on hominin teeth.</p>
<p>In fact, there is growing evidence for <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23250">grit mastication</a>, and marine molluscs are also thought to have been <a href="https://edition.cnn.com/travel/article/neanderthals-cave-gibraltar-scn-scli-intl/index.html">consumed</a>. If the fossil hominin tooth wear is caused by eating behaviour, then studying their tooth wear in more depth may give vital insight into dietary and behaviour changes during human evolution. And studying living primates today could continue to offer crucial clues that have been overlooked in the past.</p><img src="https://counter.theconversation.com/content/178246/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Towle 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>Macaque tooth wear was identical to our ancestors, throwing into question the long held belief that tool use caused the markings on hominin tooth fossils.Ian Towle, Postdoctoral researcher & teaching assistant, London South Bank UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1765692022-02-22T14:11:23Z2022-02-22T14:11:23ZThe macaque monkeys of Mauritius: an invasive alien species, and a major export for research<figure><img src="https://images.theconversation.com/files/444780/original/file-20220207-17-1eqqbum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Macaques are regarded as alien species in Mauritius. </span> <span class="attribution"><span class="source">Fabian Faber/Shutterstock</span></span></figcaption></figure><p><em>Macaque monkeys live as both captive and wild animals on the island of Mauritius. The wild population number is estimated at <a href="https://doi.org/10.1159/000156234">between 25,000 and 35,000</a> animals, it’s uncertain how many exist in captivity, but the figure is in the tens of thousands. The reason for a high captive number is that Mauritius is one of the world’s largest exporters of monkeys for the global research industry – primarily, to the US and Europe. <a href="https://www.aph.gov.au/DocumentStore.ashx?id=fa4e56d8-3755-40cc-8f69-4a2a19a39972&subId=408086">Up to 10,000</a> primates are exported by Mauritius each year. Ecologist Vincent Florens provides insights into how the animals first came to Mauritius and how their presence has affected the island’s natural environment.</em></p>
<h2>How long has Mauritius been involved?</h2>
<p>The macaques originally came from Southeast Asia and were introduced almost certainly as pets to Mauritius by the Dutch <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0053001">around</a> 1602. </p>
<p>In 1985, a private company, Bioculture, <a href="https://www.ncbi.nlm.nih.gov/books/NBK221770/">started to breed</a> the macaques for research. The government didn’t object. Macaques are closely related to humans and can help to provide data into medical issues. For instance, experimental trials in macaques <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmp.12555#:%7E:text=Experimental%20trials%20in%20macaques%20have,influenza%2C%20smallpox%2C%20and%20hepatitis.">have led researchers</a> to understand the efficacy of novel drugs and vaccines against several infectious diseases, such as AIDS, influenza, smallpox, and hepatitis.</p>
<p>Macaques were first exported from Mauritius for research <a href="https://www.ncbi.nlm.nih.gov/books/NBK221770/">in 1985</a>. Initially feral animals had to be caught to supply research. These were typically caught in the islands’ forested areas, in the national parks, nature reserves, on mountains and in woods along rivers. </p>
<p>Today they are both caught from the wild and bred in captivity for research. <a href="https://www.traveldailynews.com/post/animal-protection-groups-outraged-as-mauritius-government-gives-permission-for-capture-of-wild-monkeys">In 2020</a>, 10,827 macaques were exported from the country. </p>
<p>Wild macaques are needed to support captive breeding, an intake of at least a few thousand females each year. This is to preclude problems of genetic inbreeding that may happen in captive populations. And because captive bred animals’ breeding capacity tends to drop, and other issues like ageing of breeding animals.</p>
<h2>How does the trade affect their numbers?**</h2>
<p>The intensity of trapping feral animals may vary through time depending on the needs of the breeding programs. In times of low to no trapping the feral macaque population generally grows gradually, something I’ve observed when carrying out <a href="https://scholar.google.com/citations?user=nDUJisIAAAAJ&hl=en">research</a> on vegetation dynamics in Mauritius over about 20 years. There are more frequent calls and sightings of animals during visits to forested areas, and also by the sizes of the groups seen.</p>
<p>Conversely, there have been times of intensive trapping, like when several companies were given permits to operate several years back. This led to a very marked drop in encounters where macaques were previously abundant. </p>
<h2>What impact do macaques have on the natural environment?</h2>
<p>To appreciate the impact of macaques on Mauritius’ natural environment, one must first remember that they were introduced by humans to the island. Macaques are not part of the natural environment of Mauritius, they are like rats in that respect. </p>
<p>The macaque is what is termed an ‘alien species’ in Mauritius. This means that the many native, and often unique, animals and plants of Mauritius – which occur in one of the world’s <a href="https://www.nature.com/articles/35002501">biodiversity hotspots</a> – had no previous exposure to animals like macaques. This means the plants and animals that lived there, the endemic species, have developed no evolutionary feature that would protect them from the alien monkeys. </p>
<p>Mauritius already has one of the highest <a href="https://portals.iucn.org/library/sites/library/files/documents/RL-2000-001.pdf">extinction rates</a> of endemic species worldwide. They are among the most threatened worldwide. For example, last year, the Botanical Gardens Conservation International ranked Mauritius as the <a href="https://mauritiushindinews.com/hindi-newspaper-in-mauritius/endemic-trees-mauritius-is-a-very-bad-student-scope/#:%7E:text=The%20new%20report%20State%20of,real%20observation%20is%20even%20worse.">second worst </a> country worldwide in terms of proportion of tree species threatened with extinction. Massive deforestation <a href="https://doi.org/10.1017/S0376892914000411">is the most direct and immediate driver of biodiversity loss</a>, removing 95.6% of the original native ecosystem. </p>
<p>Macaques have, and continue to, play a pivotal role in this situation. They are formidable predators capable of <a href="https://doi.org/10.1111/j.1474-919X.1997.tb08861.x">raiding bird</a> nests to eat <a href="https://www.iucnredlist.org/species/22696373/93557909">eggs</a> and <a href="https://www.iucnredlist.org/species/22690392/179390191">chicks</a>. Macaques also chew on the soft heart of many plants like <a href="https://doi.org/10.1007/978-3-030-11257-8_29-1">orchids</a>, especially the larger species, killing them. Today orchids are the plant family that have sustained the highest <a href="https://doi.org/10.1007/978-3-030-11257-8_29-1">extinction rate</a> – 20 of the 91 known species appear to have gone extinct since 1769 in Mauritius. Many of the macaque-vulnerable orchids now cling to survival in tiny numbers in places like steep cliffs, which are least accessible to macaques. </p>
<p>Macaques destroy the fruits of many native trees before they mature. This kills the seeds within, <a href="https://www.researchgate.net/publication/252932550_Current_decline_of_the_''Dodo_Tree''_a_case_of_broken-down_interactions_with_extinct_species_or_the_result_of_new_interactions_with_alien_invaders">like those</a> of the ‘Dodo-tree’ and many ebony species. This has made forests less hospitable for native frugivores such as the endangered flying fox. </p>
<p>Macaques also destroy flowers of many species, breaking branches, and chewing on seedlings. Their activities deprive native fauna of their natural foods, which in turn contribute to their further decline. For example, macaques <a href="https://www.academia.edu/14254707/Current_decline_of_the_Dodo_Tree_a_case_of_broken-down_interactions_with_extinct_species_or_the_result_of_new_interactions_with_alien_invaders">have destroyed</a> about 95% of fruits of certain endemic trees before the Mascarene endemic flying fox has a chance to feed on these fruits. This in turn pushes the flying fox to seek food elsewhere, including on commercial trees in gardens and orchards. Sadly, this resulted in the government of Mauritius taking action against flying foxes – <a href="https://doi.org/10.1038/530033a">killing them</a> by the thousands. This has worsened the conservation status of the flying fox to <a href="https://www.iucnredlist.org/species/18743/86475525">Endangered</a> on the Red List of the International Union for Conservation of Nature.</p>
<h2>How can they be better managed?</h2>
<p>Feral macaques in Mauritius are a formidably harmful invasive alien species, destructive to many animal and plant species which are heading towards extinction in part because of the macaques. </p>
<p>The ideal management in such a situation is eradication, just like goats and rabbits were eradicated from <a href="https://doi.org/10.1016/0006-3207(86)90086-8">Round Island</a> in the 1970s and 1980s. This saved its highly threatened flora and fauna from extinction. </p>
<p>However, macaque eradication may be difficult in Mauritius’ remaining forests, which are sizeable, covering 80 km2. It may be more feasible in the short run to eradicate them from isolated pockets of habitats or to control their numbers to far below what they are now. </p>
<p>This may be done through intensive trapping or construction of macaque proof fencing, particularly in and around the most biodiversity important areas respectively. </p>
<p>Each of the monkeys that are exported annually for research is subjected to a US$125 levy that contributes to raising funds for biodiversity conservation. However, more species will continue to go extinct if the level of conservation management is not seriously increased to face the threats, including those posed by the macaques.</p><img src="https://counter.theconversation.com/content/176569/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Florens 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>Macaques are an alien species - and the endemic plants and animals of the island haven’t adapted to protect themselves against these monkeys.Vincent Florens, Associate Professor, Department of Biosciences at Faculty of Science, University of MauritiusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1739512022-02-01T17:32:17Z2022-02-01T17:32:17ZWhy monkeys attack sick members of their troop – and don’t socially distance at all<p>Life in the wild can be tough, and sometimes animals don’t have the luxury of taking time out when they are sick. That’s certainly the reality of life for vervet monkeys living in Southern Africa, even though parasites and viruses are an ever-present <a href="https://pubmed.ncbi.nlm.nih.gov/3050629/">component of animal life</a>.</p>
<p>We know how people respond to infection. Loss of appetite and staying in bed or resting are some of the ways we adapt to being unwell. Being less active and eating less frees up energy to fight the infection – even digesting food uses energy. This behaviour may help us recover and is a key component of our survival.</p>
<p>My colleagues and I wanted to understand more about how monkeys respond to illness, and how a disease travels within and between animal groups. This is essential if we are to tackle the huge impact that infection can have on monkey population survival. While the causes of infection have been the <a href="https://oxford.universitypressscholarship.com/view/10.1093/acprof:oso/9780198565857.001.0001/acprof-9780198565857">focus of much attention</a>, until now we knew very little about the social consequences of infection in these monkeys. </p>
<p>For over ten years our international team of researchers have studied the behaviour and physiology of <a href="https://www.awf.org/wildlife-conservation/vervet-monkey">wild vervet monkeys</a> living in the Eastern Cape, South Africa. They live in large social troops – up to 40 monkeys per troop – and previous research has shown that they are routinely exposed to a <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.191078#d3e2732,%20https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23962,%20https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.12329">range of environmental stressors</a> such as extreme heat and drought, as well as competition for food.</p>
<p>In our <a href="https://www.pnas.org/content/118/44/e2107881118">most recent study </a> of three groups of wild vervet monkey, we examined the effect of getting sick on individual vervet monkey’s social status.</p>
<h2>How we studied fever</h2>
<p>As with humans, when a monkey gets an infection, they can get feverish. </p>
<p>We implanted <a href="https://www.star-oddi.com/products/data-loggers/temperature-logger-implant-livestock-animals">miniature data loggers</a> - narrow cylinders about 3cm long – into each monkey’s abdomen and recorded core body temperature inside the stomach every five minutes. That allowed us to document for the first time the occurrence of fever in a wild monkey population. </p>
<p>After the study period, we returned to take the loggers out, with the help of a team of vets from the University of the Witwatersrand. We needed to do this to get the data, and obviously also for the sake of the monkeys.</p>
<p>In our study group of 59 vervet monkeys, we detected 128 fevers in 43 monkeys over seven years. Feverish monkeys reached an average (mean) daily body temperature of about 39°C, with the highest body temperature on record being nearly 42°C. Fevers lasted between two and 20 days.</p>
<p>At the same time, we kept a detailed account of the monkeys’ behaviour and social interactions. Just like us, they lose their appetite and spend more time resting. But they can’t stay out of action for too long. Even sick monkeys need to keep up with their troop if they are to keep themselves out of reach of predators, such as cheetah, jackal and caracal (a wild cat). Monkeys also rely on their group mates to help <a href="https://www.sciencedirect.com/science/article/abs/pii/S0003347216302858">fight off neighbouring troops</a> as they compete for food, water and sleep sites. </p>
<h2>The risk of attack</h2>
<p>In addition to the behavioural consequences of fever, we were able to show, for the first time, a hidden and previously unrecognised cost of social interactions – feverish monkeys were attacked while they were down. </p>
<p>Within a monkey troop, competition is rife – monkeys battle for food, status and mates. Although it’s unclear if a monkey knows that one of their troop is sick, they do recognise the weakened state of their troop mate, perhaps because they are out of sorts or are less responsive to more subtle exchanges of dominance. </p>
<p>Some individuals seemed to use this to their advantage.</p>
<p>We discovered that when monkeys were feverish they were twice as likely to be attacked by one of their group mates and six times more likely to become injured as a result. Sick animals were targeted with aggression when they were least able to fight back, potentially improving the attacker’s social status, access to resources, or position in the troop. </p>
<p>We saw a particularly unusual sequence of events in one of our troops of 25 monkeys. </p>
<p>Female vervets live in relatively stable hierarchies. But when Brie, the alpha female, fell ill she was subjected to a torrent of abuse from the troop’s beta female, Tyvara. Over seven days, Brie was attacked by her on 12 occasions and received four different injuries. Needless to say, Brie’s alpha dominance status was no more and she slipped down the hierarchy. </p>
<p>Bystanders also seemed to benefit from the weakened status of a sick individual, in this case by manoeuvring up the hierarchy, and these fever-induced social interactions are likely to have important long-term social and fitness consequences for the individuals involved. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-orangutan-mothers-help-their-offspring-learn-173959">How orangutan mothers help their offspring learn</a>
</strong>
</em>
</p>
<hr>
<p>But that’s not all. The feverish monkeys spent just as much time grooming, or being groomed, by other group members even though they were sick. While it might seem common sense to avoid other sick individuals, our findings suggest that social engagement probably reflects a trade-off between the propensity to get infected by a contagious individual and the social value and other benefits that the relationship affords – such as the ability to cope in <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.12329">difficult environments</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0003347217300362?via%3Dihub">successfully raise offspring</a>. Or perhaps monkeys simply don’t know that their troop mates are ill or could pass them a nasty illness. </p>
<p>The response of vervet monkeys to infection suggests that the spread of disease among the troop is likely. Now we have seen that there is a cost of being sociable when feverish, where vulnerable individuals are open to attack, perhaps we should turn our attention to the question of the impact of social integration among monkeys on the spread of disease within and between groups.</p><img src="https://counter.theconversation.com/content/173951/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research was funded by Faculty research grants from the University of the Witwatersrand, a Claude Leon Fellowship awarded to Richard McFarland, Natural Sciences and Engineering Research Council of Canada Discovery grants to Peter Henzi and Louise Barrett, a Canada Research Chair award to Louise Barrett, National Research Foundation of South Africa grants to Andrea Fuller, Robyn Hetem, Peter Henzi and Duncan Mitchell, a Carnegie Corporation of New York grant to Andrea Fuller, and a Harry Oppenheimer Fellowship to Duncan Mitchell.</span></em></p>Why social interaction isn’t always a good thing for primates, especially for individuals with a fever.Richard Mcfarland, Senior Lecturer in Evolution and Social Behaviour, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1677472021-09-29T15:07:12Z2021-09-29T15:07:12ZCombining an HIV vaccine with immunotherapy may reduce the need for daily medication<figure><img src="https://images.theconversation.com/files/422472/original/file-20210921-13-csnsx2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The estimated lifetime costs of antiretroviral therapy for someone who acquires HIV at age 35 is $358,380.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/therapy-pills-on-pink-background-royalty-free-image/1214095662">YakubovAlim/iStock via Getty Images Plus</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p><a href="https://doi.org/10.1126/sciimmunol.abh3034">A new combination treatment for HIV</a> can strengthen a patient’s immune response against the virus even after they stop taking traditional medications, according to a study published in the journal Science Immunology we co-led at the <a href="http://www.yerkes.emory.edu/research/divisions/microbiology_immunology/amara_rama.html">Amara Lab at Emory Univeristy</a>.</p>
<p>People with HIV take a <a href="https://hivinfo.nih.gov/understanding-hiv/fact-sheets/hiv-treatment-basics">combination of HIV medications</a> to reduce the amount of virus they have in their body. When taken as prescribed, these medications, collectively called <a href="https://www.cdc.gov/hiv/risk/art/index.html">antiretroviral therapy</a>, can reduce the amount of virus in the body to undetectable levels. Antiretroviral therapy must be <a href="https://www.hiv.gov/hiv-basics/staying-in-hiv-care/hiv-treatment/taking-your-hiv-medications-every-day">taken daily</a> so the virus is less likely to mutate and <a href="https://hivinfo.nih.gov/understanding-hiv/fact-sheets/drug-resistance">become resistant to the drugs</a>.</p>
<p>While reducing the amount of virus in the body to undetectable levels means it can <a href="https://www.niaid.nih.gov/diseases-conditions/treatment-prevention">no longer be transmitted</a>, however, the most effective antiretroviral therapy drugs are unable to completely eliminate the virus. This is because HIV hides in <a href="https://dx.doi.org/10.1084%2Fjem.190.9.1197">immune-privileged</a> areas of the body, such as certain parts of the lymphoid tissue, that are less accessible to the immune system to protect them from damage. <a href="https://doi.org/10.1038/nri819">Killer T cells</a>, which search for and eliminate infected cells, are unable to patrol these <a href="https://dx.doi.org/10.1097%2FCOH.0000000000000293">viral reservoirs</a> that harbor HIV.</p>
<p><a href="https://dx.doi.org/10.1097%2FQAD.0b013e32835ecb8b">Constant exposure</a> to the virus can push killer T cells into a <a href="https://doi.org/10.1097/qad.0000000000000314">state of exhaustion</a> in which they don’t work as well. Exhausted killer T cells display more of a protein called <a href="https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/immune-checkpoint-inhibitors.html">PD-1</a>, which functions as an “off switch” to its killing activity.</p>
<p>One way to reverse killer T cell exhaustion is to <a href="https://doi.org/10.1038/cddis.2015.162">block the PD-1 off switch</a>, but this does not boost the immune system’s response to the virus. Conversely, an HIV vaccine can significantly boost immunity against the virus. </p>
<p>So we tested whether <a href="https://doi.org/10.1126/sciimmunol.abh3034">combining these two tactics</a> could enhance HIV infection control. We administered a vaccine for <a href="https://www.livescience.com/51972-hiv-related-virus-evolutionary-history.html">SIV</a>, a close cousin to HIV, with a drug that blocks PD-1 in SIV-infected rhesus monkeys treated with antiretroviral therapy. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram illustrating immune boosting outcomes of study." src="https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422492/original/file-20210921-17-1nmhbxx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Combining a vaccine with a PD-1 blockade led to three improvements in immune response.</span>
<span class="attribution"><span class="source">Bhrugu Yagnik/Created with BioRender.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>We found that our approach generated robust anti-viral response in multiple parts of the body, including immune-privileged sites in the lymph nodes, and allowed killer T cells to infiltrate and purge viral reservoirs. Most importantly, the monkeys maintained strong immunity against the virus even after they stopped antiretroviral therapy and significantly improved their survival. None of the seven monkeys in the combination treatment group developed AIDS through our six-month follow-up period, compared with half of the monkeys who received only the vaccine or antiretroviral therapy alone.</p>
<h2>Why it matters</h2>
<p>Around <a href="https://www.unaids.org/en/resources/fact-sheet">38 million people worldwide</a> were living with HIV in 2020. If left untreated, HIV can cripple the immune system and leave the body vulnerable to <a href="https://www.hiv.gov/hiv-basics/staying-in-hiv-care/other-related-health-issues/opportunistic-infections">normally harmless infections</a>.</p>
<p>There are accessibility issues with the treatment that must be diligently taken every day for life. A 2015 study estimated that the lifetime antiretroviral therapy cost for someone who acquires HIV at age 35 is <a href="https://clinicalinfo.hiv.gov/en/guidelines/adult-and-adolescent-arv/cost-considerations-and-antiretroviral-therapy">US$358,380</a>. And many people don’t have access to daily antiretroviral therapy. Around <a href="https://www.unaids.org/en/resources/documents/2013/20131219_AccessARTAfricaStatusReportProgresstowards2015Targets">three-quarters of adults with HIV in sub-Saharan Africa</a> do not reach persistent <a href="https://clinicalinfo.hiv.gov/en/glossary/viral-suppression">viral suppression</a> due to lack of treatment availability. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram illustrating the challenges posed by HIV." src="https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422493/original/file-20210921-23-z98bip.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">HIV poses a number of challenges to both patients and researchers.</span>
<span class="attribution"><span class="source">Bhrugu Yagnik/Created with BioRender.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Finally, even though antiretroviral therapy can thoroughly suppress HIV infection, it does not cure it. There is always a risk that the virus may mutate to <a href="https://www.who.int/news-room/fact-sheets/detail/hiv-drug-resistance">become resistant to existing drugs</a>.</p>
<h2>What still isn’t known</h2>
<p>Completely wiping out HIV from the body is one way to eliminate the need for daily antiretroviral therapy. But a more achievable strategy is to put the infected cells in check. </p>
<p>Currently, only <a href="https://www.massgeneral.org/news/press-release/Hiv-new-study-of-elite-controllers-offers-powerful-evidence-that-a-cure-is-possible">0.5% of HIV positive individuals</a> are considered “<a href="https://clinicalinfo.hiv.gov/en/glossary/long-term-nonprogressors-ltnp">elite controllers</a>” who are able to suppress infection without medication. </p>
<p>While our study showed a potential pathway to control HIV, it is still in development and not ready for human patients. More research is necessary to understand how viral reservoirs form and why certain cells respond differently to different immunotherapies.</p>
<h2>What’s next</h2>
<p>A single form of therapy may not result in complete HIV remission. Our team is currently testing other drug combinations to unleash the full potential of the immune system and overcome barriers to a cure.</p><img src="https://counter.theconversation.com/content/167747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rama Rao Amara receives funding from NIAID/NIH. </span></em></p><p class="fine-print"><em><span>Bhrugu Yagnik and Sheikh Abdul Rahman do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People with HIV need to take daily medication to keep the virus at bay. A study has found that a new treatment combination could boost immunity and control virus levels even after stopping medication.Sheikh Abdul Rahman, Postdoctoral Fellow in Microbiology and Immunology, Emory UniversityBhrugu Yagnik, Postdoctoral Fellow in Microbiology and Immunology, Emory UniversityRama Rao Amara, Professor of Microbology and Immunology, Emory UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1670632021-09-01T12:43:20Z2021-09-01T12:43:20ZMonkeying about: getting to know ‘ugly’ animals better could be the key to their conservation<figure><img src="https://images.theconversation.com/files/418720/original/file-20210831-23-1vq1wok.jpg?ixlib=rb-1.1.0&rect=8%2C14%2C1908%2C1253&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Proboscis monkeys, although endangered, do not tend to receive large amounts of public conservation support.</span> <span class="attribution"><a class="source" href="https://pixabay.com/photos/proboscis-monkey-proboscis-borneo-212825/">Lekies/Pixabay</a></span></figcaption></figure><p>The current <a href="https://theconversation.com/worried-about-earths-future-well-the-outlook-is-worse-than-even-scientists-can-grasp-153091">threat</a> to the Earth’s biodiversity is no laughing matter, but it may be that raising a smile might help some vulnerable species dogged by unfortunate looks or dark reputations. </p>
<p>Studies of conservation strategies for two endangered primates – the <a href="https://www.nationalgeographic.com/animals/mammals/facts/proboscis-monkey#:%7E:text=Proboscis%20monkeys%20are%20endemic%20to,occasionally%20to%20search%20for%20food.">proboscis monkey</a> from Borneo and the <a href="https://lemur.duke.edu/discover/meet-the-lemurs/aye-aye/">aye aye lemur</a> native to Madagascar – show the surprisingly powerful influence of public attitudes towards less photogenic creatures at risk of extinction.</p>
<p>September 1 marks <a href="https://wildwelfare.org/international-primate-day-2020/">International Primate Day</a>, an opportunity to take a look at how conservationists can best raise the profiles of less-loved primates. </p>
<p>The probsocis monkey, <em>Nasalis larvatus</em>, regularly features in <a href="http://www.bbc.com/earth/gallery/20161021-feast-your-eyes-on-the-ugliest-animals-in-the-world">public votes</a> of the world’s ugliest animals. Both males and females have conspicuous noses, but <a href="https://www2.nau.edu/%7Egaud/bio300b/sexdi.htm#:%7E:text=Sexual%20dimorphism%20is%20the%20systematic,is%20larger%20than%20the%20female.&text=For%20example%2C%20the%20body%20masses,humans%20are%20approximately%20normally%20distributed.">sexual dimorphism</a> (differences in shape, size or colour between the sexes) also results in dominant males with pot bellies, piggy eyes and a vivid red penis contrasting against a black scrotum: none of which induce impressions of beauty, majesty or cuteness – the <a href="https://theconversation.com/even-ugly-animals-can-win-hearts-and-dollars-to-save-them-from-extinction-78507">usual criteria</a> for public affection. </p>
<figure class="align-center ">
<img alt="A closeup of a male proboscis monkey, Nasalis larvatus" src="https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418623/original/file-20210831-15-1rk4utm.jpeg?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 closeup of a male proboscis monkey, Nasalis larvatus.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Proboscis_monkey_(Nasalis_larvatus)_male_head.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<h2>The power of memes</h2>
<p>A <a href="https://pubmed.ncbi.nlm.nih.gov/32348597/">recent study</a> conducted in Poland aimed to illuminate ways to inspire people’s concern about protecting species, including the proboscis monkey, that aren’t so aesthetically pleasing. Researchers explored the possibility of raising public interest in conserving this curiously ugly monkey through spreading amusing internet memes – images of the monkey with text linking its appearance to Polish jokes and cultural references – within social media and in conservation marketing. The team then monitored the interest in proboscis monkeys versus conservation superstars such as <a href="https://theconversation.com/stopping-koala-extinction-is-agonisingly-simple-but-heres-why-im-not-optimistic-141696">koalas</a> and gorillas by analysing public donations made to related conservation campaigns.</p>
<p>As a result of the campaign, media interest in the proboscis monkey – virtually negligible in Poland prior to 2016 – increased <a href="https://wildlife.org/can-internet-memes-help-conserve-uncharismatic-wildlife/">significantly</a>, equalling coverage for traditional conservation celebrity species. The amusing memes, focusing on the funny side of the monkey’s looks, attracted more positive coverage that inspired several amateur crowdfunding campaigns raising money for the species’ protection in Borneo: which received <a href="https://eprints.qut.edu.au/202815/1/64825062.pdf">donations</a> from 218 donors in total.</p>
<p>Overall, a creature previously all but unknown to the Polish public became a focus of important attention that ultimately contributed to its protection by helping to pay for the conservation of its habitat. These findings suggest that conservationists shouldn’t shy away from using memes to create interest in and raise money for the more overlooked endangered members of the animal kingdom. </p>
<h2>Changing myths</h2>
<p>The aye aye lemur, <em>Daubentonia madagascariensis</em>, provides another example of the power of public attitudes to influence conservation efforts. </p>
<figure class="align-center ">
<img alt="An aye aye clings to a tree at night" src="https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418637/original/file-20210831-21-1qdibcz.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 world’s largest nocturnal primate, the aye aye is renowned for its unusual appearance.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/oregonstateuniversity/29256433783">Oregon State University/Flickr</a></span>
</figcaption>
</figure>
<p>Where the proboscis monkey is corpulent and flabby, the nocturnal aye aye is spindly, bug-eyed and unkempt. Its two front incisors stick out much like the teeth of <a href="https://www.bfi.org.uk/resources-events-teachers/resources-teachers/gothic-classroom/film-2-nosferatu-1922">Murnau’s Nosferatu</a>, complemented by an unusually elongated, skeletal central finger used to unearth grubs from trees (but also to <a href="https://www.zmescience.com/ecology/animals-ecology/cursed-yet-adorable-aye-aye-has-a-sixth-pseudothumb/#:%7E:text=According%20to%20ancient%20Malagasy%20legends,on%20sight%20by%20superstitious%20locals.">curse</a> unsuspecting humans, according to <a href="https://theconversation.com/malagasy-or-is-it-madagascan-our-research-provides-the-answer-128343">Malagasy</a> legend). Even its name, “aye aye”, is possibly a <a href="https://folklorethursday.com/regional-folklore/madagascar-superstitions-taboos-fighting-the-aye-aye-fady/">linguistic trick</a> to avoid calling the creature directly by instead imitating its cry.</p>
<p>Yet despite these creatures’ damning reputation as harbingers of catastrophe to humans, it is in fact humans who threaten the aye aye’s continued existence. Aye aye numbers have been in <a href="https://ielc.libguides.com/sdzg/factsheets/ayeaye/population">sharp decline</a> since the 1980s, thanks to hunting, deforestation of their habitat for construction and culturally driven persecution due to their “evil” reputation.</p>
<p>Although it was thought that negative perceptions of aye ayes were fairly universal in Madagascar, a <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1002/pan3.10192">recent study</a> by academics from Madagascar and Germany revealed unexpectedly varied attitudes among Magalasy villagers, with certain areas such as the <a href="https://www.researchgate.net/figure/The-Makira-Conservation-Area-of-northeastern-Madagascar_fig1_259104068">Makira region</a> of northeastern Madagascar even being potential strongholds for aye aye conservation due to the local prevalence of positive attitudes towards aye ayes.</p>
<p>In places where negative attitudes dominated, the villagers themselves often could not identify aye ayes in pictures. The animal remained an <a href="https://www.semanticscholar.org/paper/Folklore-and-beliefs-about-the-aye-aye-Daubentonia-Simons-Meyers/96b7a2939c815bd037a41427d72d6348ea256a37">unfamiliar</a>, imaginary threat.</p>
<figure class="align-center ">
<img alt="An aye aye clings to a tree at night" src="https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=609&fit=crop&dpr=1 600w, https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=609&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=609&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=765&fit=crop&dpr=1 754w, https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=765&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/418638/original/file-20210831-13-64kw0t.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=765&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aye ayes are feared in many local areas for their mythical ability to lay curses on humans.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Aye-aye_(Daubentonia_madagascariensis)_5.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>In fact, interviewees’ regard for the aye aye seemed to vary with direct knowledge of aye aye behaviour. Although negative views were more frequent than positive, the latter were associated with understanding about the aye aye’s usefulness for controlling pests on <a href="https://www.thenaturegatherer.com/ghostly-lemur-helps-farmers-madagascar/">vital crops</a>. </p>
<p>Firsthand knowledge and experience of aye ayes was associated with positive views, pointing to the importance of sharing knowledge within conservation strategy as well as the possibility of shifting seemingly entrenched beliefs.</p>
<p>In time and with patience, farmers aware of the aye aye’s pest control powers might help generate vital local action in support of conservation by helping to craft new narratives centring the creature’s role in our ecosystems. Understanding how and why people perceive certain animals as less appealing than others could be the key to expanding public conservation efforts successfully.</p><img src="https://counter.theconversation.com/content/167063/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mike Jeffries 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>Less attractive endangered species don’t tend to receive the same public attention as their more beautiful counterparts: new studies show how we might help change that.Mike Jeffries, Associate Professor, Ecology, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1619552021-06-17T15:50:12Z2021-06-17T15:50:12ZMonkeys, lemurs and apes at risk: Climate change threatens a quarter of world’s primate habitat<figure><img src="https://images.theconversation.com/files/406569/original/file-20210615-25-pgn1i1.jpg?ixlib=rb-1.1.0&rect=89%2C33%2C2387%2C1718&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The endangered golden snub-nosed monkey lives in mountainous forests of central and southwest China. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Most primates — monkeys, apes, lemurs, lorises and tarsiers — live in a tropical belt that stretches around the equator from Central and South America to Africa and Asia. But the majority of them <a href="https://www.nrdc.org/onearth/four-countries-are-home-two-thirds-planets-primates-and-most-those-are-endangered">are found in four different countries</a> — Brazil, Madagascar, Indonesia and the Democratic Republic of the Congo — so many people have not had direct contact with them. </p>
<p>Still, we may know them from films, like the <a href="https://news.cgtn.com/news/2019-09-29/Monkey-Mania-Kin-to-Jack-the-Monkey-in-The-Pirates-of-the-Caribbean-KmfYF3CJgc/index.html">capuchin in <em>Pirates of the Caribbean</em></a>, or may have heard of their stealthy abilities, like the macaques <a href="https://www.theguardian.com/science/2021/jan/14/balis-thieving-monkeys-seek-bigger-ransoms-for-high-value-swag-study">who pickpocket</a> travellers. Some are important cultural or religious symbols, <a href="http://www.luminarium.org/mythology/monkeygods.htm">like macaques</a>. </p>
<p>These animals also play key roles in their ecosystems, <a href="https://doi.org/10.1002/ajpa.23059">pollinating flowers</a> and <a href="https://doi.org/10.1007/s10329-008-0087-0">dispersing seeds</a>. Although there are around <a href="https://www.iucnredlist.org/search/grid?taxonomies=100091&searchType=species">500 primate species</a> in the world, <a href="https://doi.org/10.1126/sciadv.1600946">three-quarters</a> of them are facing population declines. </p>
<p>Because most <a href="https://doi.org/10.1038/srep25697">primates live near the equator</a>, many are especially vulnerable to climate change. In a <a href="https://doi.org/10.1007/s10584-020-02776-5">recent study</a>, my colleagues and I looked at what would happen to primate species around the world if global temperatures rose 2 C, the upper limit set by the <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement">Paris Agreement</a>. The results showed that a quarter of all primate habitat will experience prolonged heat extremes. They give conservation scientists important information on how climate change will influence primate populations in the future.</p>
<h2>New heat extremes</h2>
<p>We already know that global warming will not be uniform across the planet. The Arctic is warming faster than places closer to the equator, for example. But for animals already living in hot places, a slight increase in temperature could readily move them past a threshold and outside their comfort zone.</p>
<p>The threshold temperatures in our study represent the hottest temperature that each primate species would have faced in pre-industrial times. We then compared future average temperatures to this baseline. </p>
<p>Under the Paris Agreement, nations pledged to keep global warming to 2 C above pre-industrial levels. Yet we found that under that scenario, 26.1 per cent of all the habitats where primate species live will be hotter than their threshold temperatures. For some species, such as the patas monkey and the Senegal bushbaby in Africa, this could mean long periods throughout the year where temperatures surpass 33 C. </p>
<figure class="align-center ">
<img alt="Squirrel monkey" src="https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406570/original/file-20210615-3582-vjzewq.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">Hotter temperatures could force primates to alter their behaviours. They may eat less and produce fewer offspring.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Like humans, primates overheat and become dehydrated with continued physical activity in extremely hot weather. In a warmer future, they would have to adjust, resting and staying in the shade during the hottest times of the day. This could mean foraging less or not mating, which could limit overall food intake and change reproductive cycles.</p>
<p>Those species living in the Brazilian Amazon, along the north coast of Venezuela, the centre of equatorial Africa, the African east coast and the northwest coast of Madagascar will be most affected. Those that are already endangered, have populations occupying less than 12,000 square kilometres and are facing significant temperature increases — such as annual averages consistently above 27 C — are at greatest risk of extinction with the compounding effects of climate change. </p>
<p>For instance, the Celebes crested macaque (the <a href="https://www.npr.org/sections/thetwo-way/2017/09/12/550417823/-animal-rights-advocates-photographer-compromise-over-ownership-of-monkey-selfie">famous “monkey selfie” primate</a>) and the <a href="http://www.edgeofexistence.org/species/siau-island-tarsier/">Siau Island tarsier</a> are both critically endangered in small habitats, while currently experiencing year-round temperatures above their historic thresholds. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1329150130835005440"}"></div></p>
<p>Our analysis also showed that climate change has already pushed eight per cent of primate species habits past their thresholds. This means some populations may be facing additional stress due to hotter temperatures and changing their behaviour to compensate. These species all have declining populations and have been categorized as close to extinction — the new heat extremes could be partially to blame.</p>
<h2>Human impact</h2>
<p>It’s easy to assume that warmer global temperatures would lead to an increase in the habitat primates favour, by stretching it north and south and upwards on mountain slopes. But because of human population growth, infrastructure and agriculture, some species may not be able to move to these newly suitable areas. </p>
<p>Many primates prefer to <a href="https://doi.org/10.1007/s10531-013-0572-7">avoid us</a> and our roads, cities and fields block them from getting there. In some cases, <a href="https://www.usatoday.com/story/tech/sciencefair/2017/01/18/primates-apes-monkeys-extinction/96724398/">there is no habitat for them to move to</a>, because it has been logged, mined or degraded in some other way. </p>
<figure class="align-center ">
<img alt="endangered red-shanked douc from Vietnam" src="https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406572/original/file-20210615-3582-n2ly15.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">Most non-human primates, including the endangered red-shanked douc langur, found only in north and central Vietnam and Laos, are threatened with extinction. Climate change could make it more difficult for these species to survive.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>About <a href="https://doi.org/10.1126/sciadv.1600946">60 per cent</a> of non-human primate species are currently threatened with extinction, and climate change is only a part of it. Habitat loss, hunting, the illegal pet trade and disease have already cut back primate populations. Climate change will likely <a href="https://doi.org/10.1038/s41558-019-0508-7">increase the duration and intensity of extreme weather events</a> such as cyclones and droughts, putting more pressure on the survival of already struggling species. </p>
<h2>Conservation is key</h2>
<p>Our model did not include conservation issues, such as habitat loss, that primates are already facing. Yet the areas with the most primate species predicted to surpass temperature thresholds have also been identified as suitable for the <a href="https://doi.org/10.1016/j.cub.2014.05.077">expansion of palm oil plantations</a>. The combination of the two would only further reduce these species’ access to suitable habitat and put them at greater risk of extinction. </p>
<p>Nature reserves have been helpful in <a href="https://doi.org/10.1371/journal.pone.0105824">maintaining populations</a> of wild animals. However, the borders of wildlife reserves and protected areas are usually fixed and not easy to move. Future temperature increases could alter the habitat within a protected area so that it is <a href="https://doi.org/10.1002/ajp.22247">no longer suitable for the primate species living there now</a>. </p>
<p>Considering the <a href="https://doi.org/10.1038/ngeo2681">rapid rate</a> of climate change, future primate conservation should include predicted temperature changes in combination with the other issues that primates face. For example, wildlife reserve boundaries could be chosen based on future climatically suitable habitat for a species. Primates are amazing and fascinating animals that deserve a home on this planet alongside us.</p><img src="https://counter.theconversation.com/content/161955/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brogan M. Stewart receives funding from the Natural Sciences and Engineering Research Council of Canada, the Fonds de recherche du Québec nature and technologies, Hydro-Québec, Mitacs and the Quebec Centre for Biodiversity Science. </span></em></p>About 60 per cent of monkeys, apes, lemurs, lorises and tarsiers are threatened with extinction. Climate change will only make it more difficult for them to survive.Brogan M. Stewart, PhD Student in Environmental Science, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1578432021-04-22T12:25:43Z2021-04-22T12:25:43ZLab-grown embryos and human-monkey hybrids: Medical marvels or ethical missteps?<figure><img src="https://images.theconversation.com/files/396376/original/file-20210421-23-1cklx15.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1198%2C808&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers have grown mammal embryos later into development than ever before in an artificial womb.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Geometric_Progression.jpg#/media/File:Geometric_Progression.jpg">Vitalii Kyryk/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>In Aldous Huxley’s 1932 novel “<a href="https://www.oxfordreference.com/view/10.1093/oi/authority.20110803095525181">Brave New World</a>,” people aren’t born from a mother’s womb. Instead, embryos are grown in artificial wombs until they are brought into the world, a process called ectogenesis. In the novel, technicians in charge of the hatcheries manipulate the nutrients they give the fetuses to make the newborns fit the desires of society. Two recent scientific developments suggest that Huxley’s imagined world of functionally manufactured people is no longer far-fetched.</p>
<p>On March 17, 2021, an Israeli team announced that it had grown mouse embryos for 11 days – about half of the gestation period – in <a href="https://doi.org/10.1038/s41586-021-03416-3">artificial wombs</a> that were essentially bottles. Until this experiment, no one had grown a mammal embryo outside a womb this far into pregnancy. Then, on April 15, 2021, a U.S. and Chinese team announced that it had successfully grown, for the first time, <a href="https://doi.org/10.1016/j.cell.2021.03.020">embryos that included both human and monkey cells</a> in plates to a stage where organs began to form. </p>
<p>As both a <a href="https://scholar.google.com/citations?hl=en&user=wQsQxFoAAAAJ">philosopher and a biologist</a> I cannot help but ask how far researchers should take this work. While creating chimeras – the name for creatures that are a mix of organisms – might seem like the more ethically fraught of these two advances, ethicists think the medical benefits far outweigh the ethical risks. However, ectogenesis could have far-reaching impacts on individuals and society, and the prospect of babies grown in a lab has not been put under nearly the same scrutiny as chimeras.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tNb2npuiF3Q?wmode=transparent&start=7" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Mouse embryos were grown in an artificial womb for 11 days, and organs had begun to develop.</span></figcaption>
</figure>
<h2>Growing in an artificial womb</h2>
<p>When in vitro fertilization first emerged in the late 1970s, the press called IVF embryos “test-tube babies,” though they are nothing of the sort. These embryos are implanted into the uterus within a day or two after doctors fertilize an egg in a petri dish.</p>
<p>Before the Israeli experiment, researchers had not been able to grow mouse embryos outside the womb for more than four days – providing the embryos with enough oxygen had been too hard. The team spent <a href="https://doi.org/10.1126/science.abi5734">seven years</a> creating a system of slowly spinning glass bottles and controlled atmospheric pressure that simulates the placenta and provides oxygen.</p>
<p>This development is a major step toward ectogenesis, and scientists expect that it will be possible to extend mouse development further, possibly <a href="https://www.technologyreview.com/2021/03/17/1020969/mouse-embryo-grown-in-a-jar-humans-next/">to full term outside the womb</a>. This will likely require new techniques, but at this point it is a problem of scale – being able to accommodate a larger fetus. This appears to be a <a href="http://hdl.handle.net/10822/547926">simpler challenge to overcome</a> than figuring out something totally new like supporting organ formation.</p>
<p>The Israeli team plans to <a href="https://www.technologyreview.com/2021/03/17/1020969/mouse-embryo-grown-in-a-jar-humans-next/">deploy its techniques on human embryos</a>. Since mice and humans have similar developmental processes, it is likely that the team will succeed in growing human embryos in artificial wombs. </p>
<p>To do so, though, members of the team need permission from their ethics board. </p>
<p>CRISPR – a technology that can cut and paste genes – already allows scientists to manipulate an embryo’s genes after fertilization. Once fetuses can be grown outside the womb, as in Huxley’s world, researchers will also be able to modify their growing environments to further influence what <a href="https://doi.org/10.1093/jn/134.9.2169">physical and behavioral qualities these parentless babies exhibit</a>. Science still has a way to go before fetus development and births outside of a uterus become a reality, but researchers are getting closer. The question now is how far humanity should go down this path.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A drawing of a half–eagle, half–horse griffin." src="https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=634&fit=crop&dpr=1 600w, https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=634&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=634&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=797&fit=crop&dpr=1 754w, https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=797&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/396377/original/file-20210421-21-17un52t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=797&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chimeras evoke images of mythological creatures of multiple species – like this 15th-century drawing of a griffin – but the medical reality is much more sober.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Martin_Schongauer,_The_griffin_(15th_century).jpg#/media/File:Martin_Schongauer,_The_griffin_(15th_century).jpg">Martin Schongauer/WikimediaCommons</a></span>
</figcaption>
</figure>
<h2>Human-monkey hybrids</h2>
<p>Human–monkey hybrids might seem to be a much scarier prospect than babies born from artificial wombs. But in fact, the recent research is more a step toward an important medical development than an ethical minefield.</p>
<p>If scientists can grow human cells in monkeys or other animals, it should be possible to <a href="https://doi.org/10.1016/j.cell.2021.03.044">grow human organs</a> too. This would solve the problem of <a href="https://www.bbc.com/news/science-environment-56767517">organ shortages</a> around the world for people needing transplants.</p>
<p>But keeping human cells alive in the embryos of other animals for any length of time has proved to be extremely difficult. In the <a href="https://doi.org/10.1016/j.cell.2021.03.020">human-monkey chimera experiment</a>, <a href="https://www.bbc.com/news/science-environment-56767517">a team of researchers implanted</a> 25 human stem cells into embryos of crab-eating macaques – a type of monkey. The researchers then <a href="https://doi.org/10.1016/j.cell.2021.03.044">grew these embryos</a> for 20 days in petri dishes.</p>
<p>After 15 days, the human stem cells had disappeared from most of the embryos. But at the end of the 20-day experiment, three embryos still contained human cells that had grown as part of the region of the embryo where they were embedded. For scientists, the challenge now is to figure out how to maintain human cells in chimeric embryos for longer.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A drawing of test tubes with embryos inside." src="https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/396400/original/file-20210421-17-162zdc2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The ability to grow true test–tube babies raises many ethical questions.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/conceptual-image-of-human-cloning-royalty-free-image/1287023975?adppopup=true">Carol Yepes/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Regulating these technologies</h2>
<p>Some ethicists have begun to worry that researchers are <a href="https://doi.org/10.1016/j.cell.2021.03.044">rushing into a future</a> of chimeras without adequate preparation. Their main concern is the <a href="https://www.bbc.com/news/science-environment-56767517">ethical status of chimeras</a> that contain human and nonhuman cells – especially if the human cells integrate into sensitive regions <a href="https://doi.org/10.1016/j.cell.2021.03.044">such as a monkey’s brain</a>. What rights would such creatures have?</p>
<p>However, there seems to be an emerging consensus that the potential medical benefits justify a step-by-step extension of this research. Many ethicists are urging <a href="https://doi.org/10.1016/j.cell.2021.03.044">public discussion</a> of appropriate regulation to determine how close to viability these embryos should be grown. One proposed solution is to limit growth of these embryos to the first trimester of pregnancy. Given that researchers don’t plan to grow these embryos beyond the stage when they can <a href="https://doi.org/10.1016/j.cell.2021.03.044">harvest rudimentary organs</a>, I don’t believe chimeras are ethically problematic compared with the true test–tube babies of Huxley’s world.</p>
<p>Few ethicists have broached the problems posed by the ability to use ectogenesis to engineer human beings to fit societal desires. Researchers have yet to conduct experiments on human ectogenesis, and for now, scientists lack the techniques to bring the embryos to full term. However, without regulation, I believe researchers are likely to try these techniques on human embryos – just as the now-infamous He Jiankui <a href="https://thehill.com/opinion/healthcare/422891-how-we-proceed-with-human-gene-editing-will-be-the-debate-of-the-future">used CRISPR to edit human babies</a> without properly assessing safety and desirability. Technologically, it is a matter of time before mammal embryos can be brought to term outside the body. </p>
<p>[<em>Over 100,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p>
<p>While people may be uncomfortable with ectogenesis today, this discomfort could pass into familiarity as happened with IVF. But scientists and regulators would do well to reflect on the wisdom of permitting a process that could allow someone to engineer human beings without parents. As <a href="https://doi.org/10.1002/j.1552-146x.2011.tb00098.x">critics have warned</a> in the context of CRISPR-based genetic enhancement, pressure to change future generations to meet societal desires will be unavoidable and dangerous, regardless of whether that pressure comes from an authoritative state or cultural expectations. In Huxley’s imagination, hatcheries run by the state grew a large numbers of identical individuals as needed. That would be a very different world from today.</p><img src="https://counter.theconversation.com/content/157843/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sahotra Sarkar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Researchers have grown the first human-monkey hybrid embryos as well as mouse embryos in artificial wombs late into development. These biomedical breakthroughs raise different ethical quandaries.Sahotra Sarkar, Professor of Philosophy and Integrative Biology, The University of Texas at AustinLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1505982020-11-24T15:00:38Z2020-11-24T15:00:38ZThe world’s newest monkey species was found in a lab, not on an expedition<figure><img src="https://images.theconversation.com/files/370884/original/file-20201123-23-1y2ibtb.jpg?ixlib=rb-1.1.0&rect=0%2C331%2C3469%2C2324&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Popa langur, photographed in early 2020.</span> <span class="attribution"><span class="source">Aung Ko Lin, Fauna & Flora International</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The discovery of the <a href="https://www.bbc.co.uk/news/science-environment-54894681">Popa langur</a>, a medium-sized leaf-eating monkey found in central Myanmar, was recently announced by scientists. It is estimated there are just 200-250 of these monkeys, which will likely mean the new species is classed as “critically endangered”. This find was announced just a week or so after <a href="https://www.nature.com/articles/s41598-020-76364-z">two new species of greater glider</a> – a gliding marsupial – were identified in Australia. But what do scientists mean when they announce the discovery of “new” mammalian species? Were these animals really unknown to science?</p>
<p>While discoveries such as the langur and the gliders are certainly exciting, it is important to clarify that these were not previously unseen species uncovered by some intrepid explorer. Rather, these animals have been identified as a genetically distinct group within an already-known population. In fact, local people have been living with these animals for generations, and have their own ways of identifying and classifying species. When scholars announce a newly defined species based on genetic evidence, it usually means they have elevated an already defined subspecies to the species level. </p>
<p>Species are <a href="https://theconversation.com/curious-kids-what-is-a-species-107402">not as clear-cut as they seemed </a> when we first learned about them in school. Most scholars use the “biological species concept”, which is based on whether the animals are able to produce fertile offspring together, but there are many other ways to define a species. Like most other recently-described primates, the Popa langur has been <a href="https://theconversation.com/why-theres-been-a-boom-in-discovering-new-species-despite-a-biodiversity-crisis-99475">identified using genetic information</a>, or the phylogenetic species concept. This is based on how animals relate to other groups in evolutionary terms, essentially defining a species as the smallest group that can be genetically distinguished from another species but still shares a clear ancestor.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Golden buildings on top of a steep rocky summit." src="https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371064/original/file-20201124-19-17c2yxd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The monkeys are mostly found on and around Mount Popa, which is also known for its spectacular monastery.</span>
<span class="attribution"><span class="source">Avigator Fortuner / shutterstock</span></span>
</figcaption>
</figure>
<p>Elevation of a subspecies to new species based on genetic information can be controversial. Some scholars dismiss these discoveries as “taxonomic inflation”, and worry that changing classifications <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/evan.21387?casa_token=EXPnEmZkSkIAAAAA:KZkyajgfXMe7pLbzyUZXQMIxCfaOlP1esftr5ivYuKC0gcNGxGmulquYz1n88Id2mG74rN_rQNstLw">can confuse conservation efforts</a>. Others note that without a name and reliable population estimate, these little pockets of genetic variation could easily go extinct without notice, and that elevating them to species level <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1693347/pdf/15253356.pdf">ensures that conservation funding and efforts</a> are directed to these at-risk groups. Wherever you stand, it is worth noting that the idea of a species – under any definition – is a human construct to explain variation in the natural world, and no definition will be a perfect representation of biological variation.</p>
<h2>Identifying a new species</h2>
<p>The <a href="http://www.zoores.ac.cn/en/article/doi/10.24272/j.issn.2095-8137.2020.254">newly described Popa langur</a> was discovered through a phylogenetic study which sought to better understand the evolutionary relationships among the 20 known species of the genus <em>Trachypithecus</em> – known informally as the langurs, lutungs, or leaf monkeys. Scientists used faecal samples from wild langurs and tissue samples from museum specimens to clarify taxonomic relationships across the genus.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black monkey with blue face sits on branch." src="https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=509&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=509&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370888/original/file-20201123-23-168usze.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=509&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Phayre’s langur has lost some of its population to ‘new’ species.</span>
<span class="attribution"><span class="source">Ezaz ahmed Evan / shutterstock</span></span>
</figcaption>
</figure>
<p>One group of langurs stood out – the genetic evidence showed that there were clear western and eastern varieties, but that a central population did not fit into either of these. The western and eastern varieties, which were previously named subspecies of Phayre’s langur, were then elevated to the species level (Phayre’s langur or <em>Trachypithecus phayrei</em> and the Shan State langur or <em>T. melamera</em>, respectively). The remaining population was called <em>Trachypithecus popa</em> – the Popa langur, after nearby Mount Popa. This newly defined species lives in four distinct populations, and is at risk of extinction due to its small numbers, deforestation, and the effects of agriculture and timber extraction.</p>
<p>It may come as a surprise to hear that a newly-discovered species is at risk of extinction, but this is often the case with genetic reclassifications. The two previously named subspecies from which the Popa langur was identified were already classified as “endangered” under the official <a href="https://www.iucnredlist.org/species/22040/17960739">International Union for Conservation of Nature (IUCN) red list criteria</a>, which means that these already-threatened animals now have an even smaller population than previously believed. Both of those subspecies – Phayre’s and the Shan State langur, now species in their own right – will need to be re-evaluated for extinction risk. The Popa langur has not yet been classified but the study authors suggest that it should fall under the category of “critically endangered”, due to its small and fragmented population and the limited habitat it has available.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Small furry creature clings to branch" src="https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370885/original/file-20201123-23-1xm353m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aye-ayes are more scientifically valuable than any single species of langur.</span>
<span class="attribution"><span class="source">javarman / shutterstock</span></span>
</figcaption>
</figure>
<p>Genetic reclassifications can be an important reminder to focus conservation efforts at higher taxonomic levels. For example, the <a href="https://www.nationalgeographic.com/animals/mammals/a/aye-aye/">aye-aye</a>, an odd nocturnal primate found in the forests of Madagascar, represents a monospecific genus – a genus with only a single living species. There is no living creature quite like an aye-aye, so its extinction would be a great loss of genetic, ecological, and behavioural diversity. The Popa langur, by contrast, is one of roughly 20 species in the langur genus <em>Trachypithecus</em>, who all share a relatively recent evolutionary history. </p>
<p>Nevertheless, the identification of each new primate species tells us a little more about the diversity of this fascinating order of mammals. By understanding that the Popa langur is genetically distinct from neighbouring populations, we can better prioritise conservation efforts for this group of animals. This new classification will be vital for generating conservation funds to protect this rare monkey and its environment.</p><img src="https://counter.theconversation.com/content/150598/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tracie McKinney is affiliated with the International Union for Conservation of Nature (IUCN) as part of the Primate Specialist Group Section for Human-Primate Interactions.</span></em></p>How scientists discovered the ‘Popa langur’ was a separate species of just 200 monkeys.Tracie McKinney, Senior Lecturer in Human Biology, University of South WalesLicensed as Creative Commons – attribution, no derivatives.