Cultural gorillas

There's lots of news this week from the AAAS meetings. One story reports on behavioral variations among zoo gorillas:

Behavioral surveys of the roughly 370 gorillas in U.S. zoos showed 48 variations in how individual groups of the apes make signals, use tools and seek comfort, said Tara Stoinski of Zoo Atlanta and the Dian Fossey Gorilla Fund International.
"What became very obvious is there is a very distinct pattern of similarities and differences between groups," Stoinski said.
That suggests the gorillas pass along the different traits socially, not genetically, which is a hallmark of culture. Results were presented Sunday at the annual meeting of the American Association for the Advancement of Science.

Not unexpected, since all the other great apes clearly have these kinds of behavioral traditions. But until better field comparisons of wild gorilla populations are available, this kind of work has to fill in the gaps.

Personally, I wonder whether much of the noticeable variation among chimpanzee populations is reinforced by their larger group sizes. If behaviors are lost or changed through the lack of reinforcement from other individuals, then larger groups ought to help retain them over a longer time span -- and all other things being equal, should result in more traditions and greater interpopulation differences. Gorillas and orangutans ought to have a disadvantage in this regard -- somewhat mitigated by the occurrence of extractive foraging (i.e. using tools to process or obtain food), which is relatively high in orangutans but also present in gorillas.

On the subject of chimpanzees, the same article reports this:

As for chimps, recent videos, described Sunday to reporters by Whiten, show the apes in the Congo using a "tool kit" to collect and eat termites.
The chimps first use a large stick to tunnel a foot deep into termite mounds. They then pull out the large stick and use a more slender piece of vegetation that they've frayed to fish out the insects through the shaft they've created, Whiten said.

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May I suggest, Chimp-o-Rooter?