Filming chimpanzee gestures.

The Sonso community of chimpanzees has its own reality television show. However, the show isn’t on any cable network; it’s for the benefit of science. By capturing the chimps’ daily lives and interaction on camera, researchers hope to understand how their gestures evolved and find clues to the origins of human language. Catherine Hobaiter, a field primatologist from St. Andrews University, Scotland, has spent the past 6 years filming the chimpanzees at the Budongo Conservation Field Station in Uganda. Although chimpanzee gestural communication has been studied in captivity for about 20 years, Hobaiter and her colleagues were the first to study it extensively in the wild. Studying these chimpanzees is quite an arduous task, involving 12to 13-hour days spent following the chimpanzees around a hot, humid rainforest. “It’s possibly the worst possible environment to film in, because it’s wet, it’s dark, the chimps run on and off camera, you have to crawl through swamps, you get army ants in your socks, and everything possible gets in the way,” Hobaiter says. There’s a reason for all that effort. Captive groups generally have only 10–15 individuals in very simple environments, but “I have 80 individuals in my group, and you have patriarchs and grandmas and mothers and newborn infants, and they cover tens of kilometers of rainforest and they have fights with the neighboring communities, and there’s just this amazing context,” she says. Understanding that context is crucial to figuring out how chimpanzee communication evolved. Hobaiter has captured and classified thousands of hours of video footage of the chimpanzees as they gesture to one another. This extensive observation allows researchers to discover the meanings of individual gestures, and the group finds that wild chimpanzees use about 66 different gestures to communicate with each other. “They target them to a specific recipient, and they do that with a specific goal in mind,” Hobaiter says. Several gestures are very similar to those of humans: having your palm up is a begging gesture and pushing away with your hand means “go away,” she says. Hobaiter recently discovered that the Sonso chimpanzees appear to share a common repertoire of available gestures with all other chimpanzees that have ever been studied in captivity or at other wild sites. “That’s one of our bigger findings; it’s something you could never have looked at in captivity,” Hobaiter says. Many other animals have species-typical repertoires for communicating, and it even bears similarities to the finite number of phonemes, or set of speech sounds, that humans share despite speaking different languages. Hobaiter’s group plans to extend their field studies to other chimpanzee communities and eventually to other Great Ape species that they currently study only in captivity. Comparing communication methods between communities and species would illuminate the evolutionary origins of communication across the Great Apes, including humans. Individuals from the Sonso community of chimpanzees groom each other, as a researcher films them to capture the gestures they use to communicate. Image courtesy of Liran Samuni.