Wednesday, December 21, 2005

Ape stories for everyone

Robert Sapolsky's article about apes and human nature is really good. One of the big themes of the piece is about how cultural factors have a huge role in explaining how apes behave.

This first excerpt is about Forest Troop, a troop of savanna baboons whose more aggressive males all got killed by eating tainted meat they found on a raid. This left only the girls and a bunch of laid-back dudes:

In a typical savanna baboon troop, newly transferred adolescent males spend years slowly working their way into the social fabric; they are extremely low ranking -- ignored by females and noted by adult males only as convenient targets for aggression. In Forest Troop, by contrast, new male transfers are inundated with female attention soon after their arrival. Resident females first present themselves sexually to new males an average of 18 days after the males arrive, and they first groom the new males an average of 20 days after they arrive (normal savanna baboons introduce such behaviors after 63 and 78 days, respectively). Furthermore, these welcoming gestures occur more frequently in Forest Troop during the early post-transfer period, and there is four times as much grooming of males by females in Forest Troop as elsewhere. From almost the moment they arrive, in other words, new males find out that in Forest Troop, things are done differently.

At present, I think the most plausible explanation is that this troop's special culture is not passed on actively but simply emerges, facilitated by the actions of the resident members. Living in a group with half the typical number of males, and with the males being nice guys to boot, Forest Troop's females become more relaxed and less wary. As a result, they are more willing to take a chance and reach out socially to new arrivals, even if the new guys are typical jerky adolescents at first. The new males, in turn, finding themselves treated so well, eventually relax and adopt the behaviors of the troop's distinctive social milieu.

Then there was this:

Optimizing the fission-fusion interactions of hunter-gatherer networks is easy: cooperate within the band; schedule frequent joint hunts with the next band over; have occasional hunts with bands somewhat farther out; have a legend of a single shared hunt with a mythic band at the end of the earth.

For sheer love-of-mythology reasons, I was totally goosebumped-out by the "legend of a single shared hunt with a mythic band at the end of the earth" part. That is so damn cool.

No comments: