Calls in the wild.

Calls in the wild

Wild chimpanzees seldom bunch together in a large congregation, preferring to intermingle in a number of smaller groups as they make their way through the jungle. Preliminary observations in Tanzania's Gombe Stream National Park suggest these groups frequently communicate with each other over long distances by exchanging disinctive calls, according to a report in the spring ANTHROQUEST.

Individual chimpanzees may travel toward a group emitting the calls, or one group may head toward another after an exchange, says anthropologist Christopher Boehm of Northern Kentucky University in Highland Heights, who works in collaboration with Jane Goodall of the Gombe Stream Research Center. Chimps often volley calls back and forth in succession between groups, Boehm notes, indicating "a two-way conversational aspect [with] some similarity to human language."

In the summer of 1986, Boehm and Tanzanian field assistants taped each end of two-way communications between chimp groups. The assistants made additional tapes after Boehm left and sent them to him for analysis.

Long-distance communications chiefly involved "pant-hoots," Boehm says, a type of call with many poorly understood variations. Pant-hoots are based on the rapid inhaling and exhaling of air, beginning in a low register and building toward a high-frequency climax.

Within a community, chimps know one another's voices and can locate another group after a brief call, Boehm maintains. Thus, when groups take turns in vocalizing, they are doing more than announcing their location. Boehm and a colleague hope to conduct a four-year study in which they will look for rules governing turn-taking and attempt to identify specific pant-hoots given in reponse to preceding calls.

They also plan to videotape interactions between individual chimps and conduct a spectographic analysis of the grunts and other calls emitted in various situations.