The dog-human connection in evolution

ResearchBlogging.orgEvolutionary theorists have long recognized that the domestication of animals represented a major change in human life, providing not just a close-at-hand food source, but also non-human muscle power and a host of other advantages. Penn State anthropologist Prof. Pat Shipman argues that animal domestication is one manifestation of a larger distinctive trait of our species, the ‘animal connection,’ which unites and underwrites a number of the most important evolutionary advances of our hominin ancestors.

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Shipman’s proposal is discussed in a recent forum paper in Current Anthropology and is the subject of her forthcoming book, The Animal Connection. The paper is interesting to us here at Neuroanthropology.net because Shipman indirectly poses fascinating questions about the evolutionary significance of human-animal relationships, including the cognitive abilities of both and how they interact.

As Shipman puts it in the Penn State press release about the research, if we only think about what domesticated animals do for us as a species, we miss the truly curious thing about our relationship to them:

No other mammal routinely adopts other species in the wild — no gazelles take in baby cheetahs, no mountain lions raise baby deer…. Every mouthful you feed to another species is one that your own children do not eat. On the face of it, caring for another species is maladaptive, so why do we humans do this?

Although researchers working on symbiotic inter-species relationships might highlight that the support of other species hardly requires adopting their young and feeding them canned kitten food (a critique Travis Pickering levels in his comments), Shipman’s statement highlights nicely that human-animal inter-species relationships seem to extend beyond merely treating them as tameable prey or means to a human end. But then again, this super-instrumentality could be ascribed to a large number of human traits.

The domestication of animals wasn’t merely about capturing a buffet-on-the-hoof, from Shipman’s perspective, but the continuation of a long-term evolutionary project by our species to study animals, first when we were prey for them, and later as predators ourselves.

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Squirrels as Models for Human Behavior? Indeed!

A delightful article on squirrel behavior, biology, and sociality today highlights just how great a model squirrels can be for some true comparative research. Here’s another species with phenomenal elasticity, good learning and sociality, and even specialized brain and body parts!

Behind the squirrel’s success lies a phenomenal elasticity of body, brain and behavior. Squirrels can leap a span 10 times the length of their body, roughly double what the best human long jumper can manage. They can rotate their ankles 180 degrees, and so keep a grip while climbing no matter which way they’re facing. Squirrels can learn by watching others — cross-phyletically, if need be.

In the acuity of their visual system, the sensitivity and deftness with which they can manipulate objects, their sociability, chattiness and willingness to deceive, squirrels turn out to be surprisingly similar to primates. They nest communally as multigenerational, matrilineal clans, and at the end of a hard day’s forage, they greet each other with a mutual nuzzling of cheek and lip glands that looks decidedly like a kiss.

The gray squirrel is diurnal and has the keen eyesight to match. “Its primary visual cortex is huge,” said Jon H. Kaas, a comparative neuroscientist at Vanderbilt University, A squirrel’s peripheral vision is as sharp as its focal eyesight, which means it can see what’s above and beside it without moving its head.

“We’ve seen seeds that were recached as many as five times,” said Dr. Steele. The squirrels recache to deter theft, lest another squirrel spied the burial the first X times. Reporting in the journal Animal Behaviour, the Steele team showed that when squirrels are certain that they are being watched, they will actively seek to deceive the would-be thieves. They’ll dig a hole, pretend to push an acorn in, and then cover it over, all the while keeping the prized seed hidden in their mouth. “Deceptive caching involves some pretty serious decision making,” Dr. Steele said. “It meets the criteria of tactical deception, which previously was thought to only occur in primates.”

Link to Natalie Angier’s Nut? What Nut? The Squirrel Outwits to Survive article

Dave Matthews’ Monkey Tales

“I think at every opportunity we need to say, Wow, well, I’m a monkey.” Entertaining interview with Dave Matthews on Q with Jian Ghomeshi, part of CBC radio. All about vervet monkeys. Matthews is quite the story teller!

For those of you looking to explore vervet monkeys’ lives more, I recommend Dorothy Cheney & Robert Seyfarth’s 1992 book on their research on vervets, How Monkeys See the World: Inside the Mind of Another Species.

Cheney and Seyfarth’s 2008 book is on their work with baboons, and is a great read about primate behavior, the evolution of mind, and understanding ourselves from a comparative perspective: Baboon Metaphysics: The Evolution of a Social Mind.

Matthews’ last story, about male vervet monkeys’ family jewels, is entirely true. I’ve included some vivid photographs if you just click for more. The blue color of the scrotum actually varies according to dominance status – a bright, vivid blue is connected with higher male status. Show offs!

For that research, see Gerald (2001), Primate colour predicts social status and aggressive outcome.

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Chimps with Photographic Memories

Chimpanzees can routinely beat the best humans at instant memory recall. Here’s the blurb:

Ben Pridmore ranks in the number two spot for worldwide memory competitions, can memorize the order of a full deck of cards in only 30 seconds, and regularly memorizes numbers up to 400 digits long. But in a test performed by the British television program “Extraordinary Animals,” Pridmore’s performance fell far short of that of a seven-year-old male chimpanzee named Ayumu.

Imitating the format of a scientific study in which Ayumu had formerly participated, both human and chimpanzee watched a screen on which five numbers were displayed briefly before being replaced by white boxes. They then had to touch the blank boxes in the order of the numbers they had formerly displayed.

When the numbers were shown for only a fifth of a second, Ayumu still scored 90 percent correct; Pridmore’s score, on the other hand, was only 33 percent.

But in this video, you can see that the chimps take it up to 9! (No, not 11, that only happens in Spinal Tap.)

There is an entire YouTube bio on Ayumu, where you can also see more of the memory training. You can even try the memory game yourself! It’s freakin’ hard!

Here’s the reference for the 2007 article on chimp working memory by the Japanese researchers Sana Inoue and Tetsuro Matsuzawa. Or you can cheat, I’m sorry, help yourself to opened access and get the whole pdf.

For more on their and other Japanese scientists’ work, check out their home institution, the Primate Research Institute at Kyoto University.

Cooperative Hunting by Chimpanzees

The following video is the best illustration I have ever seen of how chimpanzees hunt together in coordinated fashion, with different individuals having different roles. It combines both on-the-ground video and overhead infrared to illustrate just how this group of chimpanzees manages a successful hunt of colobus monkeys. Incredible footage!

(If it doesn’t play, try going directly to the You Tube clip.)

Christophe Boesch has spear-headed the research to document hunting roles among chimpanzees. He published on cooperative hunting in a 1994 Animal Behaviour article (pdf) and discussed hunting roles, meat sharing, and learning more specifically in a 2002 Human Nature article (pdf).

Craig Stanford is another researcher who has focused on hunting by chimpanzees. He has written this online essay, The Predatory Behavior and Ecology of Wild Chimpanzees, which is an excellent overview of what we know about chimpanzee predatory behavior.

John Mitani has also published on why male chimpanzees hunt and share meat; in 2002 John also provided an overview about recent developments in the study of wild chimpanzee behavior. I posted more video on chimpanzee behavior, including hunting, just this week – so check that out for more footage.

For what chimpanzee hunting means about our own evolution, we have two contrasting views – hunters vs. being hunted. Craig Stanford has a 2001 popular book The Hunting Ape: Meat Eating and the Origins of Human Behavior. That book should be tempered by the more recent Man the Hunted: Primates, Predation and Human Evolution.

Chimpanzees: Too Close for Comfort

Back in 1992, David Attenborough narrated the film Too Close for Comfort, a documentary on chimpanzee life and behavior in the Tai Forest. The Tai Forest is a national park in Cote d’Ivoire in West Africa. The film centers on the work of Christophe Boesch and Hedwige Boesch-Achermann, who have been working in the Ivory Coast for years. Together the two wrote the book The Chimpanzees of the Tai Forest: Behavioral Ecology and Evolution.

I use this film in my Introduction to Anthropology class, it just has some extraordinary footage. Mike Richards, the cameraman, spent two years on this project! Here is one clip, where the chimps are filmed cooperatively hunting colobus monkeys. Wow.

There are four other clips available:

Closest links to man – the intro to the movie and the Tai chimps

Hard nuts to crack – the chimps cracking nuts with tools

Fall of Brutus – the confrontation between two dominant males that takes place over a bonanza of nuts

Eat them before they eat you – where chimps use tools to eat safari ants and a leaf sponge to drink water

Christophe Boesch has his extensive publications available for download at the Max Planck Institute for Evolutionary Anthropology. One recent publication is: Is Culture a Golden Barrier between Chimpanzees and Humans? where he argues that chimpanzees display a broad cultural repertoire, similar to humans. He wrote a 2001 piece for Scientific American on The Cultures of Chimpanzees. And if you want to know more about cooperative hunting, here’s a 2002 Human Nature paper on that.

Update: I have posted another spectacular video of chimpanzee hunting, including infrared views of their group tactics from the air as they hunt a pack of colobus monkeys.

Foxy Evolution

Here’s a great video that shows how selection can work its effects–in this case artificial selection, demonstrated through the work of the Russian Dmitri Belyaev and his tame silver foxes. Still, what I find most striking about this video is the analogy to ourselves.

Jim Rilling, a neuroanthropologist at Emory, once commented to me that humans are wired to cooperate (in his latest work, he’s doing neuro-imaging on what happens when people don’t reciprocate, having researched the neural bases of cooperation earlier). The example Jim used has stuck with me ever since. Imagine 50 chimpanzees trying to sit down and watch an introductory lecture together. Pandemonium with those chimps. For us, it’s the most mundane sort of thing. People do it everyday around the world.

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