If that’s the case, chimpanzees will never join the culture club. “None of us,” anthropologist William McGrew admits, “knows what significance chimpanzees attach to some of the weird and wonderful things they do.” Still, Whiten and his colleagues have shown that chimps can imitate complex behaviors step by step (though they never teach one another deliberately). The longer primatologists study chimpanzees and the more their findings are compared, the longer the list of unique learned behaviors grows.
Taken together, those traits may open a window on early human behavior as well. For example, according to a recent survey of five long-term chimp studies, the most sociable chimps tend to be best at using tools (captive chimps, by the same token, are better with tools than wild chimps). That pattern may help explain how early hominids, despite their smaller brains, gradually developed complex cultures. After all, fossil evidence shows that early humans only began to use tools after their canines (which they may have used to fight one another) began to shrink.
To get a less theoretical sense of how chimp culture and human culture are related, you might try standing quietly in Kibale National Park and listening hard. Chances are, instead of the monotonous sound of nut-cracking, you’ll hear something more complex: a hollow knocking, a double-time thump-thumping that echoes through the trees.
Chimpanzees, you’ll find, can drum.
The trees at Kibale and other sites often have huge buttresses that rise several yards from the leafy litter to the canopy overhead. By slapping at the buttresses with their hands, chimps can create rhythmic patterns that can carry for more than a mile. Adam Clark Arcadi, an anthropologist at Cornell University, has spent four years collecting these sounds. To do so, he and his research assistants simply stand in the forest and point a directional microphone toward a drummer. Later, back in his lab, Arcadi runs the recording through a sophisticated computer program that creates images of the sound. From that image he can measure differences in rhythm and pitch among drummers.
Chimp drumming is a male thing, as far as we know. Males do it throughout the day, most often when on the move, with each bout lasting anywhere from a few seconds to almost half a minute. Like jazz drummers knocking out a riff, each chimp seems to have a signature beat. “There are differences in the speed at which they drum, and in slaps that come in pairs—ba-dump-ba-dump-ba-dump—versus single beats—dump-dump-dump,” Arcadi explained one day, hitting his desk to demonstrate. Like people, chimps can be righties or lefties, and they probably favor their better hand when drumming. When Arcadi played some of his drumming tapes, spliced together into a continuous loop, it sounded like elementary jazz.
All chimpanzees presumably drum to communicate with one another (though no one knows what they’re communicating). But Arcadi has found that males at Kibale often drum without calling, whereas males in Taï National Park usually pant-hoot as well. One could say, therefore, that chimpanzee drumming is multicultural. Maybe there’s even a link between what chimps pound out in the forest and the sounds that their human counterparts make on a Saturday night.
To deepen our concept of their culture, primatologists will have to learn more about chimps’ interpersonal relationships. Do chimps from various sites treat each other differently? Are the customs and manners of East African chimps as different from those of West African chimps as, say, Samoans’ are from Icelanders’? Are males more repressive toward females at one site and more easygoing at another, echoing the variety of human male-female relationships across the globe? In the words of primatologist Frans B.M. de Waal, who observes chimpanzee social behavior at the Yerkes Primate Field Station in Atlanta: “Who fishes for ants and who doesn’t, or who cracks nuts and who doesn’t—that’s the easy thing to see. But the social dynamics, that’s much harder to put your finger on.”
Who knows what’s left to discover? “I now regard chimpanzees as a very big mystery,” says anthropologist Vernon Reynolds, who works in Uganda’s Budongo Forest. “The more we find out, the less we understand.” McGrew agrees: “I have been struck by the richness of chimpanzee nature. There is always a new twist on an old theme that causes you to smile and revise yet another set of conclusions. There is such a wonderful wealth of stuff here.”
Late in the fall, Jane Goodall took some time away from her most recent book tour—and plans for yet another African safari—to talk about the chimp culture studies. The new findings hardly come as a surprise, she said. “I wrote an article in 1973 saying that the big challenge now, the most important thing, is to learn about cultural variation.” As for the definition of culture, she still uses the one she has always used: “It’s simple. You just have to prove that the behavior is passed down through observational learning rather than instinct.”
Nevertheless, the studies that Goodall set in motion so long ago are quickly carrying us beyond such simple answers. Perhaps chimpanzees are more guided by cultural rules in their day-to-day interactions than we realize. Or perhaps some of the activities that we consider patently cultural—in humans as well as chimps—are really shaped by the environment.
“I don’t think everything humans do is cultural,” says cultural anthropologist Lee Cronk of Rutgers University. In one Kenyan tribe, for instance, tradition dictates that boys are more desirable than girls, yet parents consistently treat girls better. The reason, Cronk says, is that girls in that area are more likely than boys to give their parents grandchildren. Culture may urge one behavior, but biology urges another—and the latter wins out.
“Culture isn’t what we do,” Cronk concludes, “it’s the information that we share that tells us what’s appropriate to do. It’s not the act of baking a cake; it’s the recipe.” The trick is determining when we’re improvising and when we’re cooking by the book. What part of marriage, for instance, is biological and what part cultural? “Culture is complicated when it comes to humans,” Cronk admits. “But with chimps it’s relatively simple. You can get your mind around it. It allows you to see very clearly that they behave in many ways with no cultural input. When people see that, it’s easier to convince them that, yeah, culture isn’t the only thing that is influencing human behavior.”
Goodall’s definition of culture, cut-and-dried as it sounds, still smudges such distinctions. For decades she has been the preeminent authority on chimpanzees, and her major work, The Chimpanzees of Gombe, has been a kind of bible to primatologists. Published in 1986, its 673 pages once seemed to contain everything one could ever want to know about chimps. These days, though, when you get it down from the bookshelf, you notice that the pages have yellowed, and that a damp, musty library smell rises from them. The Chimpanzees of Gombe no longer seems a sacred text, but a piece of history.
And soon, it may be a relic.