On the list of animals at risk are several endangered species.
- SARS-CoV-2 enters our cells by binding with ACE2 receptors.
- A study finds many animals may provide a similar point of entry for the infection.
- COVID-19 has already been seen in a range of non-humans.
ACE2<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU4MTgwMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMTI3NDU4NH0.BceDb6l6wcwImHgniUPCNX_F5NeJ8vSsrAWNH7DG-x0/img.jpg?width=980" id="2fb6e" class="rm-shortcode" data-rm-shortcode-id="77a7d2b0d83cfc72479f2b9089e512ac" data-rm-shortcode-name="rebelmouse-image" alt="3D illustration of SARS-CoV-2 binding with ACE2 receptors" />
3D illustration of SARS-CoV-2 binding with ACE2 receptors
Image source: Kateryna Kon/Shutterstock<p>SARS-CoV-2's main point of entry into our systems, its main cellular receptor, is an angiotensin converting enzyme-2 known as ACE2. There are many types of cells and tissues in humans that contain ACE2, including the epithelial cells found in the mouth, nose, and lungs. SARS-CoV-2 binds to 25 ACE2 amino acids to get into our cells.</p><p>The researchers investigated the presence of these amino acids in other organisms on the assumption that their presence would provide SARS-CoV-2 entry to their cells as they do in ours. Says first author of the study <a href="https://www.ucdavis.edu/person/articles/27275" target="_blank">Joana Dama</a> of UC Davis, "Animals with all 25 amino acid residues matching the human protein are predicted to be at the highest risk for contracting SARS-CoV-2 via ACE2."</p><p>The precise mechanism by which SARS-CoV-2 infections occur and lead to COVID-19 is still under exploration. Nonetheless, the study operates on the principle that more of the 25 amino acids an animal has, the higher its risk of infection. "The risk is predicted to decrease the more the species' ACE2 binding residues differ from humans," says Dama.</p>
Which species are at risk?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU4MTgwMi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYwMzA5ODY4Nn0.oZHKdhpvHJjihgp2R3E23hMotY-yazjh0vCw5S_L2F8/img.png?width=980" id="3130d" class="rm-shortcode" data-rm-shortcode-id="8edb6a4f609576554b9067ee019ab08b" data-rm-shortcode-name="rebelmouse-image" alt="species risk chart" />
Image source: Matt Verdolivo/UC Davis<p>Their analysis leads Dama and her co-authors to the conclusion that about 40 percent of the species at risk of SARS-CoV-2 infection are on the International Union for Conservation of Nature's <a href="https://www.iucn.org/resources/conservation-tools/iucn-red-list-threatened-species" target="_blank">"threatened" list</a>.</p><p>Sumatran orangutans, Northern white-cheeked gibbons, and the Western lowland gorillas are all critically endangered and are vulnerable to infection. Some marine animals are also at high risk, including bottlenose dolphins and gray whales.</p><p><span></span>The study asserts that many animals most likely to live among humans are apparently at low risk, including cats, dogs, cattle, sheep, horses, and pigs. Chinese hamsters carry a high risk.</p><p>It's worth noting, however, that there <em>are</em> cases on record of SARS-CoV-2 infections in <a href="https://www.statnews.com/2020/05/13/cats-can-catch-covid-19-from-one-another-study-finds-the-question-is-can-we/" target="_blank">cats</a> and <a href="https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/sa_by_date/sa-2020/sa-06/sars-cov-2-dog" target="_blank">dogs</a>. <a href="https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa325/5811871" target="_blank">Hamsters</a>, too. Less likely house pets like <a href="https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2020/ny-zoo-covid-19" target="_blank" rel="noopener noreferrer dofollow">lions, tigers</a>, and <a href="https://www.npr.org/sections/goatsandsoda/2020/06/25/882095588/dutch-minks-contract-covid-19-and-appear-to-infect-humans" target="_blank">mink</a> have also been infected.</p><p>Bats, the presumed <a href="https://www.nature.com/articles/s41586-020-2012-7" target="_blank" rel="noopener noreferrer dofollow">source of SARS-CoV-2</a>, are found by the study to be at very low risk of infection due to a lack of ACE2 receptors. Other experimental data lines up with the study's finding, which suggests that spread of SARS-CoV-2 from bats is likely to have involved intermediate hosts en route to infecting humans.</p><p>The authors have made available for <a href="https://www.pnas.org/highwire/filestream/945399/field_highwire_adjunct_files/1/pnas.2010146117.sd01.xlsx" target="_blank">download</a> the full list of animals its authors find may be susceptible to SARS-CoV-2 infection.</p>
Animal exposure to SARS-CoV-2<p>Lead author Harris Lewin explains the importance of the research:</p><p>"The data provide an important starting point for identifying vulnerable and threatened animal populations at risk of SARS-CoV-2 infection. We hope it inspires practices that protect both animal and human health during the pandemic."</p><p>The study finds the same 40 percent of animals may also be especially likely to encounter the infection through human contact. The main locus of such interaction cited by the study is zoos. (Both the <a href="https://nationalzoo.si.edu/animals/news/covid-19-update" target="_blank">National Zoo</a> and the <a href="https://zoo.sandiegozoo.org/videos?playlistVideoId=6151893073001" target="_blank" rel="noopener noreferrer dofollow">San Diego Zoo</a> contributed genetic material to the researchers for the study.)</p><p>Co-author Klaus-Peter Koepfli of the Smithsonian-Mason School of Conservation explains that zoo personnel already guard against such transmissions, saying, "Zoonotic diseases and how to prevent human to animal transmission is not a new challenge to zoos and animal care professionals." The study makes keeping animals and humans apart at zoos more urgent than ever, though, and "this new information allows us to focus our efforts and plan accordingly to keep animals and humans safe."</p>
Big brains come at a big cost, however.
- A recent study examined the relationship between brain size and the development of motor skills across 36 primate species.
- The researchers observed more than 120 captive primates in 13 zoos for over seven years.
- The results suggest that primates follow rigid patterns in terms of which manipulative skills they learn first, and that the ultimate complexity of these skills depends on brain size.
Fig. 1 Eight food manipulation categories and their order of emergence during ontogeny. Ninety-seven percent of all observed species (N = 36) and 82% of all observed individuals (N = 128) strictly followed this ontogenetic sequence.
Heldstab et al.<p style="margin-left: 20px;">"Our results show that the neural development follows extremely rigid patterns -- even in primate species that differ greatly in other respects," Sandra Heldstab, an evolutionary biologist in the Department of Anthropology at the University of Zurich, said in a <a href="https://www.media.uzh.ch/en/Press-Releases/2020/Dexterity.html" target="_blank">press release</a>.<br></p><p>For the study, the researchers observed 128 primates in 13 European zoos over seven years, recording more than 10,000 observations from the time the animals were born until they reached adult-level dexterity. The team found that smaller-brained primates, like lemurs, start learning simple motor skills at an earlier age than larger-brained primates, like chimpanzees.</p>
Heldstab et al.<p>But the wait pays off for larger-brained primates: They're eventually able to perform more complex tasks with their hands, like using tools, or moving both hands simultaneously to move multiple objects.</p><p style="margin-left: 20px;">"It is no coincidence that we humans are so good at using our hands and using tools, our large brains made it possible," Heldstab said. "A big brain equals great dexterity."</p><p>It seems inefficient that primates, like chimps and humans, undergo such a long period of learning and dependency. But the researchers suggest this represents a fitness tradeoff: primate parents and children spend more time on development, but it leads to complex skills that help them get more food, and survive longer. In other words, animals don't evolve to perform complex manipulative tasks unless it significantly prolongs lifespan.</p>
William Vanderson / Stringer<p>So, what does this mean for the evolution of other animals? The researchers say their findings imply that if a species is going to make and use tools, it needs to have "reached a sufficiently slow life history pace to permit such a change in their foraging niche." In other words, the baby giraffe that hits the ground running might be good at escaping predators, but don't expect it to do something like <a href="https://www.youtube.com/watch?v=qEk_sNYAyCo" target="_blank">build a primitive fishing rod to "fish" for algae</a>.</p><p style="margin-left: 20px;">"Our study shows once again that in the course of evolution, only mammals that live a long time and have enough time to learn were able to develop a large brain and complex fine motor skills including the ability to use tools," Heldstab said. "This makes it clear why so few species could follow our path and why humans could become the most technologically accomplished organism on this planet."</p>
Some fish evolved legs and walked onto the land. Right?
Evolution explains how all living beings, including us, came to be. It would be easy to assume evolution works by continuously adding features to organisms, constantly increasing their complexity.
An orangutan has settled into a Florida home after a court granted her personhood rights. But what is the basis for personhood?
- An orangutan named Sandra was granted non-human personhood rights in 2015 and has been moved from the Buenos Aires Zoo to a home in Florida.
- Legal personhood is not synonymous with human being. A "non-human person" refers to an entity that possesses some rights for limited legal purposes.
- Sentience might be the characteristic necessary for granting legal rights to non-human species.
Non-human person definition<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="34b8dc86facdf829e69fc81c3e42d4f0"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/proXzAtbRzI?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>According to <a href="https://www.law.cornell.edu/wex/legal_person" target="_blank">legal terminology</a>, legal personhood is not exactly synonymous with human being. The law divides the world between two entities: things and persons. <a href="https://www.forbes.com/sites/andreamorris/2018/03/13/can-you-be-a-person-if-youre-not-human/#c1b2c212f7f1" target="_blank">According</a> to the Nonhuman Rights Project executive director, attorney Kevin Schneider, personhood is best understood as a container for rights. Things have no rights, but once an entity is defined as a person it can obtain some rights. So, a "non-human person" refers to an entity that is guaranteed some rights for limited legal purposes.</p><p>In Sandra's case, the ruling undercut species-membership as the basis for legally denying rights, freedoms, and protections. The Association of Officials and Lawyers for Animal Rights <a href="https://www.reuters.com/article/us-argentina-orangutan/captive-orangutan-has-human-right-to-freedom-argentine-court-rules-idUSKBN0JZ0Q620141221" target="_blank">based its argument</a> that Sandra should not be treated as an object based on the orangutan's "sufficient cognitive functions." But <a href="https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1394&context=animsent" target="_blank">others have argued</a> that it is sentience, rather than cognitive complexity, that is the essential characteristic for granting legal rights to non-human species.</p><p>The judge in Sandra's case agreed, telling the Associated Press that by giving Sandra non-human person status she wanted to shift society's view on other-than-human beings by telling them that "animals are sentient beings and that the first right they have is our obligation to respect them." </p>
Degrees of Sentience<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjA4MTg0MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMzI1MzkyM30.9rE_CDx9IeZdF7ckvbrCAu8X6HJb8QrPlYzI7BK3BBA/img.jpg?width=1245&coordinates=0%2C258%2C0%2C259&height=700" id="f672e" class="rm-shortcode" data-rm-shortcode-id="9092960947796b49e2e5b9f4bc4aea40" data-rm-shortcode-name="rebelmouse-image" />
Photo Source: Wikimedia<p>Sentience is defined as the ability to perceive one's environment and translate those perceptions into various feelings, such as suffering or pleasure. This has little to do with a species' cognitive ability. </p><p>It's been argued that it is <a href="https://www.reuters.com/article/us-argentina-orangutan/captive-orangutan-has-human-right-to-freedom-argentine-court-rules-idUSKBN0JZ0Q620141221" target="_blank">inappropriate to humanize</a> animal behavior in this way. Yet, science can never be totally free from this anthropomorphism, and there's a solid argument as to why.</p><p>For one, humans can only ever think about animals by drawing on their own experiences, and this facilitates many of the research questions when studying other species. Yet, beyond scientific discovery, there is an ethical motivation for relating human emotions to animal experiences. Once we accept that other species might feel pain similar to what we feel, we become responsible for their suffering. </p><p>Anthropomorphism, when used responsibly, can add emotional meaning to the science of animal sentience. </p><p>But is there a distinction to be made between sentient species? After all, we are animals. Yet, humans differentiate ourselves from other types of animals. Our culture, and the taxonomies our fields of study rely on, demand categorizations of nature. But nature is not so obedient. </p><p>Research indicates that sentience extends to a wide range of animals. For example, chimps have been found to be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3158226/" target="_blank">generous</a>, mice have <a href="https://www.ncbi.nlm.nih.gov/pubmed/16809545" target="_blank">exhibited empathy</a> and honeybees have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3158593/" target="_blank">demonstrated pessimism</a>. But because of the limits of human perception, we don't have sufficient ways to measure just <em>how</em> sentient non-human species are. It likely isn't a clear-cut answer of sentient or not sentient, but <a href="https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1343&context=animsent" target="_blank">shades of grey</a>. </p><p>Currently, most of the research on animal sentience has focused on vertebrate species and been mammal-centric. It is generally accepted that vertebrates (with the disputable exception of fish) are sentient, and that <a href="https://www.tandfonline.com/doi/abs/10.1207/S15327604JAWS0402_9" target="_blank">invertebrates are less-so</a>. These evolving distinctions have made nonhuman personhood protections a messy legal area. </p><p>Admittedly, humans have something these other sentient beings apparently do not: The cognitive ability to create complex cultures which have allowed us to conceive of and communicate a claim of rights. But, as environmental researcher Uta <a href="https://animalstudiesrepository.org/animsent/vol3/iss23/2/" target="_blank">Maria Juergens has argued</a>, "If we pride ourselves on our unique intellect, we ought to also pride ourselves on assuming the responsibility that comes with it."</p>
Experts argue the jaws of an ancient European ape reveal a key human ancestor.
- The jaw bones of an 8-million-year-old ape were discovered at Nikiti, Greece, in the '90s.
- Researchers speculate it could be a previously unknown species and one of humanity's earliest evolutionary ancestors.
- These fossils may change how we view the evolution of our species.
Rethinking humanity's origin story<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTQwNzQyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYwNDYyMDY0Nn0.aHF-2w0zRWpAulb1zE_RDn3gXcAvODm_5lyQwt2ycvY/img.jpg?width=1245&coordinates=0%2C17%2C0%2C22&height=700" id="fbc85" class="rm-shortcode" data-rm-shortcode-id="70d8bb829b135530ca5dec10a7a02b95" data-rm-shortcode-name="rebelmouse-image" />
The frontispiece of Thomas Huxley's Evidence as to Man's Place in Nature (1863) sketched by natural history artist Benjamin Waterhouse Hawkins. (Photo: Wikimedia Commons)<p>As reported in <a href="https://www.newscientist.com/article/mg24232263-300-did-the-ancestor-of-all-humans-evolve-in-europe-not-africa/" target="_blank"><em>New Scientist</em></a>, the 8- to 9-million-year-old hominin jaw bones were found at Nikiti, northern Greece, in the '90s. Scientists originally pegged the chompers as belonging to a member of <em>Ouranopithecus</em>, an genus of extinct Eurasian ape.</p><p>David Begun, an anthropologist at the University of Toronto, and his team recently reexamined the jaw bones. They argue that the original identification was incorrect. Based on the fossil's hominin-like canines and premolar roots, they identify that the ape belongs to a previously unknown proto-hominin.</p><p>The researchers hypothesize that these proto-hominins were the evolutionary ancestors of another European great ape <em>Graecopithecus</em>, which the same team tentatively <a href="https://www.newscientist.com/article/2132026-our-common-ancestor-with-chimps-may-be-from-europe-not-africa/" target="_blank">identified as an early hominin in 2017</a>. <em>Graecopithecus</em> lived in south-east Europe 7.2 million years ago. If the premise is correct, these hominins would have migrated to Africa 7 million years ago, after undergoing much of their evolutionary development in Europe.</p><p>Begun points out that south-east Europe was once occupied by the ancestors of animals like the giraffe and rhino, too. "It's widely agreed that this was the found fauna of most of what we see in Africa today," he told <em>New Scientists</em>. "If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?"</p><p>He recently outlined this idea at a conference of the American Association of Physical Anthropologists.</p><p>It's worth noting that Begun has made similar hypotheses before. Writing for the <em>Journal of Human Evolution </em>in 2002, Begun and Elmar Heizmann of the Natural history Museum of Stuttgart discussed a great ape fossil found in Germany that they argued could be the ancestor (broadly speaking) of all living great apes and humans. </p><p style="margin-left: 20px;">"Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa," <a href="https://www.sciencedaily.com/releases/2002/02/020219075535.htm" target="_blank">Begun said in a statement then</a>. "It suggests that the great ape and human lineage first appeared in Eurasia and not Africa."</p>