Saturday, May 05, 2007

Favorite Mammals Episode IX: Big groups, big brains

Episode 9: The Social Climbers is the penultimate in the BCC's Life of Mammals series. It focuses on the brain power of monkeys and larger primates who have developed intellects that solve the problems of their environments by passing on "cultural" traditions, using tools, and navigating the difficulties of group dynamics.

The stars of the episode include:

Capuchins - These proto-typical monkeys are shown rummaging through the forest with characteristic curiousity. Their brains capture, process and communicate to others any valuable lessons learned on their various ventures. We see them put to use two particular generational discoveries: how to open closely closed-up clams and the benefits of anti-septic leaves that they rub on their bodies to heal and protect against bug bites.

Toque Macaques - From Sri Lanka, these monkeys have a complex society that's been carefully studied. It's a rigid class system that bestows great priveleges on the highly ranked, and to navigate through the political and sexual dynamics of the society requires a lot of strategizing. They're certainly not stupid, as Senator George Allen's "macaca" insult at a debate last year might have implied, but they are also not very democratic.

Baboons - These primates inhabit the grasslands that developed as the rain forest receded 10 million years ago. Residing in such open spaces makes them more vulnerable to predators, and to compensate for that they live in large groups. The group dynamics here reward males who develop friendships through social grooming and who take care of the group's females and young -- certainly a more admirable meritocracy than the macaques.

Gelada - These primates live on the highlands of Ethiopia and form the largest herds. They are also the only grazing primates -- scooting on their rear ends to pick grass with their fingers. Males conduct show battles (including the very attractive lip flip) to establish social dominance, and the winners lord it over "harems" of females. Since their hands are preoccupied with grass-picking, rather than grooming to form social bonds the Gelada "talk" to each other with vocal chatter that might give clues to how our own ancestors' first developed language.

One of the most interesting details noted in the show is that scientists have discovered a direct correlation between primate brain size and group size. Social complexity requires a more developed intellect, and the environmental conditions that drove primates out of the trees and into the plains may have been the key evolutionary moment that led to our own development of language and eventually consciousness.

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