From Barbara King of the Friday Animal Blog:

This spring, I’m once again teaching my Primate Behavior course at William & Mary. Back in the mid-1980s, I cut my academic teeth on a similar course at the University of Oklahoma, and since coming to Williamsburg—over 20 years ago—I’ve offered Primate Behavior every single teaching year. Somehow, I always find it fresh and exciting because we primatologists are continually finding out unexpected things about monkeys and apes.
In class recently, the book Chimpanzees of the Tai Forest by Swiss biologists Christophe Boesch and Hedwige Boesch-Achermann provoked lively discussion. Written a decade ago, this volume has rapidly joined works by Jane Goodall in becoming a classic of long-term chimpanzee research. The Boesches worked in Tai Forest, Cote d’Ivoire, on the west coast of Africa, and thus introduce readers to a site across the continent from Goodall’s famous Gombe in Tanzania.
At Tai, just like at Gombe, chimpanzees live in big mixed-sex communities. Males stay in the communities into which they are born, but females transfer to another community at adolescence—and spend their lives there. But the cross-continent similarities are limited. At Tai, male and female adult chimpanzees express close emotional bonds as a matter of course, adults expertly crack open hard nuts using hammers and anvils, and adult males collaborate in complex ways when they hunt colobus monkeys. Gombe chimpanzees do none of these things.
Is this ape culture at work?
Yes, I think so: The variations are learned socially, and cannot be explained away by differences in ecology from one site to another. After all, hard nuts are found at Gombe, and Gombe chimpanzee males do relish the eating of colobus monkeys. (The ape-culture picture would be of much less interest if the nuts were absent from Gombe or if the Gombe apes were vegetarians).
This isn’t to imply that environment doesn’t matter at all. The Tai chimpanzees inhabit dense forest, and surely their behavior has been shaped by that fact. Maybe, for instance, visibility is lower in the forest and this acted as a selection pressure for greater coordination among male hunters. (Intriguingly, anthropologists are pretty sure nowadays that our own evolution started out in the forests—not the open savannas as originally thought.)
But it’s clearly social factors that most influence the expression of the different behaviors. The Boesches bring this fact alive by profiling individual chimpanzees from Tai. We meet Brutus, an alpha male who is renowned (among the scientists, at least!) for his sophisticated hunting techniques. Brutus, when he hunts, anticipates the movements of both his prey and of his fellow chimpanzee hunters—a feat called “double anticipation” that requires serious brain power. By apprenticing with Brutus, the young male called Ali gained hunting knowledge at a rate far faster than normally seen.
We also meet Ricci, whose daughter Nina tries valiantly to open a hard nut with a hammer, but fails. After eight minutes of Nina’s trying, Ricci approaches her, and Nina immediately hands her mother the hammer. Ricci very slowly and deliberately rotates the hammer to show her daughter the best position for nut-cracking. Nina copies her mother and cracks nuts successfully.
Taking a cue from my sociocultural anthropology colleagues, I’d like to see ape-culture studies become more about patterns of daily meaning-making by the apes, as exemplified in these vignettes from Brutus’ and Ricci’s lives, and less about which populations carry out this tool-using or that hunting behavior.
Rigorous field work on ape lives—aided by 21st-century technology in video and audio analysis—has much more to reveal to us about our closest living relatives.