A Bit More Detail

Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘chimpanzees

[LINK] “Mysterious Chimpanzee Behavior May Be Evidence of “Sacred” Rituals”

The Dragon’s Tales linked to a remarkable paper, “Chimpanzee accumulative stone throwing”.

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

The full paper is accessible via the link above.

One of the authors, Laura Kehoe, wrote an extended article for Scientific American.

We paused at a clearing in the bush. I let out a sigh of relief that no thorns appeared to be within reach, but why had we stopped? I made my way to the front of the group to ask the chief of the village and our legendary guide, Mamadou Alioh Bah. He told me he had found something interesting—some innocuous markings on a tree trunk. Something that most of us wouldn’t have even noticed in the complex and messy environment of a savannah had stopped him in his tracks. Some in our group of six suggested that wild pigs had made these marks, while scratching up against the tree trunk, others suggested it was teenagers messing around.

But Alioh had a hunch—and when a man that can find a single fallen chimp hair on the forest floor and can spot chimps kilometres away with his naked eye better than you can (with expensive binoculars) as a hunch, you listen to that hunch. We set up a camera trap in the hope that whatever made these marks would come back and do it again, but this time we would catch it all on film.

[. . .]

What we saw on this camera was exhilarating—a large male chimp approaches our mystery tree and pauses for a second. He then quickly glances around, grabs a huge rock and flings it full force at the tree trunk.

Nothing like this had been seen before and it gave me goose bumps. Jane Goodall first discovered wild chimps using tools in the 1960s. Chimps use twigs, leaves, sticks and some groups even use spears in order to get food. Stones have also been used by chimps to crack open nuts and cut open large fruit. Occasionally, chimps throw rocks in displays of strength to establish their position in a community.

But what we discovered during our now-published study wasn’t a random, one-off event, it was a repeated activity with no clear link to gaining food or status—it could be a ritual. We searched the area and found many more sites where trees had similar markings and in many places piles of rocks had accumulated inside hollow tree trunks—reminiscent of the piles of rocks archaeologists have uncovered in human history.

Videos poured in. Other groups working in our project began searching for trees with tell-tale markings. We found the same mysterious behaviour in small pockets of Guinea Bissau, Liberia and Côte d’Ivoire but nothing east of this, despite searching across the entire chimp range from the western coasts of Guinea all the way to Tanzania.

This, surely, is proof of chimpanzee minds.

Written by Randy McDonald

March 1, 2016 at 6:01 pm

[LINK] “Chimpanzee language claims lost in translation, researchers conclude”

The Dragon’s Tales linked to this press release.

Research published earlier this year claiming chimpanzees can learn each others’ language is not supported, a team of scientists concludes after reviewing the study.

The scholarship in question, published in the journal Current Biology in February, centered on the examination of two sets of chimpanzees in the Edinburgh Zoo: one that had been captive for several years in the facility and one that had recently arrived from the Beekse Bergen Safari Park in the Netherlands. Over a three-year period, the researchers claimed that the latter set had altered their sounds to those of the former set when communicating about a common object, apples, resulting in what they saw as a newly shared vocalization.

The original study team, which included faculty from the University of York, the University of Zurich, and the University of St. Andrews, posited that the findings “provide the first evidence for vocal learning in a referential call in non-humans.” This was offered as evidence that chimpanzees can learn different calls for the same object, which was widely interpreted as an important finding for the study of language evolution.

But a review of the Current Biology study by researchers at the German Primate Center in Göttingen, the University of Kent, and New York University, suggests these conclusions are off-base.

“There are a number of problems with the original study,” observes James Higham, an assistant professor in NYU’s Department of Anthropology and a co-author of the new analysis, which also appears in Current Biology. “Some of these relate to the methods used while others are fundamentally a misrepresentation of what the data actually show.”

Written by Randy McDonald

November 10, 2015 at 10:27 pm

[LINK] “Wild chimps learn from others to make new tools”

CBC reports on a recent paper suggesting that chimpanzees, like humans, can transmit elements of material culture between each other. We all learn, and share.

It’s not just humans who want the latest gadget. Wild chimpanzees that see a friend making and using a nifty new kind of tool are likely to make one for themselves, scientists report.

“Our study adds new evidence supporting the hypothesis that some of the behavioural diversity seen in wild chimpanzees is the result of social transmission and can therefore be interpreted as cultural,” an international research team writes today in the journal PLOS Biology.

The findings suggest that the ability of individuals to learn from one another originated long ago in a common ancestor of chimpanzees and humans, the researchers add.

“This study tells us that chimpanzee culture changes over time, little by little, by building on previous knowledge found within the community,” said Thibaud Gruber, a co-author of the study, in a statement. “This is probably how our early ancestors’ cultures also changed over time.”

Scientists already knew that chimpanzees in different groups have certain behaviours unique to their group, such as using a particular kind of tool. They suspected that wild chimpanzees learn those behaviours from other chimpanzees within their group, as scientists have observed in captive chimps. But they could never be sure.

The new study documents the spread of two new behaviours among chimpanzees living in Uganda’s Budongo Forest. It shows that chimps learned one of them — the making and use of a new tool called a moss sponge — by observing other chimps who had already adopted the behaviour. Chimps dip the tool in water and then put it in their mouth to drink.

Written by Randy McDonald

October 1, 2014 at 11:04 pm

[LINK] “Scientists Translate Chimpanzee and Bonobo Gestures That Resemble Human Language”

Wired‘s Brandon Keim reports on claims by scientists to have observed what might be proto-language among chimpanzees, one based on gestures.

It will be interesting to watch this develop. It is noteworthy that chimpanzees can’t speak because they’re physically unable to, and that other primates like the famous Koko the gorilla have mastered sign language. What was going on unnoticed in the wild?

Scientists have described the communications of chimpanzees and bonobos in new and unsurpassed detail, offering a lexicon for our closest living relatives and even a glimpse into the origins of human language.

The research, contained in two new studies published July 3 in Current Biology, focuses on physical gestures. These are the primary form of communication in bonobos and chimps, used more readily than vocalizations.

One study describes how a certain bonobo gesture conveys an informational complexity not previously observed in non-human great apes. The other study identifies the meanings of no fewer than 36 chimpanzee gestures.

“What we’ve shown is a very rich system of many different meanings,” said primatologist Richard Byrne of Scotland’s University of St. Andrews, co-author of the chimpanzee study. “We have the closest thing to human language that you can see in nature.”

Byrne’s co-author, fellow University of St. Andrews primatologist Catherine Hobaiter, spent 18 months observing a group of chimpanzees in the Budongo Forest Reserve in western Kenya. Hobaiter painstakingly documented more than 4,500 gestures in 3,400 incidents of chimp-to-chimp gesturing, noting both the motions used and the responses of nearby chimps.

Subsequent statistical analysis boiled those observations down to 36 established gestures and 15 clear-cut meanings. (Multiple gestures are sometimes used for the same purpose, perhaps conveying some not-yet-understood nuance.) Stomping two feet, for example, is used to initiate play. Reaching means, “I want that,” and an air-hug embrace is a request for contact.

Written by Randy McDonald

July 4, 2014 at 7:33 pm

[BLOG] Some Tuesday links

  • blogTO covered, with abundant photos, last night’s substantial rainstorm. (126 millimetres, I was given to understand by CBC this morning.)
  • Crooked Timber celebrates its tenth anniversary.
  • Geocurrents’ Asya Pereltsvaig maps the origins of servicement in the American military. It turns out that saying that they come from red states is an oversimplification (among other things).
  • GNXP notes that the “aquatic ape” theory of human origins is accurate at least inasmuch as human populations, unlike chimpanzee populations, aren’t divided into separate subspecies by major rivers. (We can swim.)
  • Marginal Revolution starts a comment thread speculating as to how democracy might disappear from the world.
  • The Power and the Money’s Noel Maurer notes that Argentina isn’t going to follow the American precedent and start electing judges.
  • Charlie Stross wonders about the future of democracy inasmuch as party politics is declining while a meta Ruling Party takes over.
  • Science blogger Supernova Condensate is also going to blog about his experience as a scientist working in Japan.
  • Towleroad’s coverage of the news that two American cancer patients also infected with HIV were apparently cured of the latter via a bone marrow transplant is correct in noting that this provides clues for a cure.
  • Window on Eurasia suggests that terrorist threats against the Sochi Olympics in Russia by Chechens will lead to a tightening of Russian control over the North Caucasus.

[BLOG] Some Monday links

  • Bag News Notes features multiple interesting brief photo essays: one about the downloadable gun; one about the woman miraculously rescued from the wreckage of the factory in Bangladesh; one about how modernism, done right, can be quite beautiful.
  • At Beyond the Beyond, Bruce Sterling links to a critique of the English words and terms used by European Union officials and to a description of the post-democratic “info-state”.
  • Crooked Timber commemorates the conviction of former Guatemalan dictator Efrain Rios Mott by noting that Ronald Reagan spoke highly of him.
  • At A Fistful of Euros, Edward Hugh introduces the work of a blogger who suggests that, between emigration and the consequences of a low birth rate, Portugal’s economy is set to crater.
  • At Lawyers, Guns and Money, Robert Farley considers Edward Hugh’s suggestion that some countries might face state failure as depopulation proceeds.
  • Marginal Revolution’s Tyler Cowen seems to like Feedly as an alternative to Google Reader.
  • Naked Anthropologist Laura Agustín blogs about the way in people transgressed identities–national, occupational, and so on–can be quite commonsensical while others who don’t get this can be stuck.
  • Savage Minds interviews journalist and anthropologist Sarah Kendzior about experience in her two professions.
  • Strange Maps links to a map of chimpanzee and bonobo populations in central Africa, divided not only by their behaviour (the first violent, the second sexual) but by the Congo River.
  • Une heure de peine’s Denis Colombi tackles the idea that French emigrants are refugees fleeing a hostile environment at home, as opposed to being mobile professionals in a global workplace.
  • The Volokh Conspiracy’s Ilya Somin argues that judicial rulings legalizing same-sex marriage have not harmed same-sex marriage at the ballot box.
  • Window on Eurasia touches on the ethnic divisions among Russian Buddhists–Kalmyks, Tuvans, Buryats–that is preventing the establishment of a Buddhist sanctuary in Moscow.

[LINK] “Lab chimps successfully treated with anti-depressants”

Via io9 I came across Pallab Ghosh’s BBC report suggesting that anti-depressants could be quite useful for chimps freed from research colonies. With the obvious provisos that this has to be done carefully, under controlled conditions, if this report is accurate I’m pleased. Especially after reading Andrew Westoll’s award-winning book The Chimps of Fauna Sanctuary: A Canadian Story of Resilience and Recovery, describing how chimps at a rehab facility in Québec suffered terribly and in ways recognizable to humans from their long captivity, and in light of things like the National Institutes of Health’s retirement of its chimp colonies, doing something to help these intelligent animals seems morally imperative.

Dr Godelieve Kranendonk, a behavioural biologist leading the study at AAP, a rescue centre for animals in the Netherlands, told BBC News that the results had been astonishing.

“Suddenly, [the chimps] woke up. It was as if they were zombies in their enclosures and now they are happy, playing with each other. They are chimps again – that was really nice to see,” she told me.

[. . .]

Staff at the AAP sanctuary care for the animals until they die. They try to rehabilitate them so that they can live out their remaining years happily.

The chimps are fed a good diet of vegetables, have toys and plenty of space in which to play. But Dr Kranendonk found that the abnormal behaviour actually increased. It was as if the animals did not know how to cope with their new found freedom.

Dr Kranendonk decided to consult Martin Bruene, a professor of human psychiatric disorders at the University of Bochum, Germany. He prescribed a course of anti-depressants for five of the chimps.

All the animals had been used in medical experiments and were infected with Hepatitis C. “Willy” showed the least abnormal behaviour. “Tomas” and “Zorro”, on the other hand, would spend a third of their waking hours eating their own vomit.

“Iris” had lost so much weight from vomiting when she first came to the sanctuary that the staff thought she would die.

The most troubled though was “Kenny”, a small chimp who was constantly anxious that the others would attack him and spent much of his time screaming in terror.

The chimps were given SSRI (Selective Serotonin Reuptake Inhibitors), which is a class of anti-depressant similar to Prozac and is used to treat human patients for depression, anxiety disorder and obsessive compulsive disorder.

After six to eight weeks, the animals behaviour started improving. The abnormal behaviour declined and the chimps began to play together. After seven months, there was a vast difference.

[. . .]

The big question though is whether the effect lasts when the chimps are taken off the medication. The early indications are promising. The medication has been steadily reduced and there has been no adverse effect on the chimps’ behaviour.

Kenny himself decided that he did not want to take the anti-depressants anymore. His clownish behaviour has continued.

“It seems that while on the medication, the chimps learn to be chimps again,” said Dr Kranendonk. “And once they have learned that, they don’t need the medication any more.”

Written by Randy McDonald

February 20, 2013 at 3:59 am

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