Bonobo body proportions have been compared with those of the australopithecines, a form of prehuman. Coolidge-the American anatomist who gave the bonobo its eventual taxonomic status-suggested that the animal might be most similar to the primogenitor, because its anatomy is less specialized than is the chimpanzees. It could most closely resemble the common ancestor of all three modern species.

If this evolutionary scenario of ecological continuity is true, the bonobo may have undergone less transformation than either humans or chimpanzees. (Given the species slow rate of reproduction, the rapid destruction of its tropical habitat and the political instability of central Africa, there is reason for much concern about its future.) Their present range lies in humid forests south of the Congo River, where perhaps fewer than 10,000 bonobos survive. In contrast, bonobos probably never left the protection of the trees. The subsequent divergence of the chimpanzee and the bonobo lines came much later, perhaps prompted by the chimpanzees need to adapt to relatively open, dry habitats. The split between the human line of ancestry and the line of the chimpanzee and the bonobo is believed to have occurred a mere eight million years ago.

THIS FINDING commands attention because the bonobo shares more than 98 percent of our genetic profile, making it as close to a human as, say, a fox is to a dog. So bonobos share at least one very important characteristic with our own species, namely, a partial separation between sex and reproduction. A female gives birth to a single infant at intervals of between five and six years. Despite the frequency of sex, the bonobos rate of reproduction in the wild is about the same as that of the chimpanzee. And sexual interactions occur more often among bonobos than among other primates. Bonobos engage in sex in virtually every partner combination (although such contact among close family members may be suppressed). Whereas in most other species sexual behavior is a fairly distinct category, in the bonobo it is part and parcel of social relations-and not just between males and females. The species is best characterized as female-centered and egalitarian and as one that substitutes sex for aggression. satyrus-which refers to the myth of apes as lustful satyrs-would have been perfect for the bonobo. The old taxonomic name of the chimpanzee, P. But I believe a different label might have been selected had the discoverers known then what we know now. The bonobo was officially classified as Pan paniscus, or the diminutive Pan. But soon the animal was assigned the status of an entirely distinct species within the same genus as the chimpanzee, Pan. Schwarz declared that he had stumbled on a new subspecies of chimpanzee. A German anato-mist, Ernst Schwarz, was scrutinizing a skull that had been ascribed to a juvenile chimpanzee because of its small size, when he realized that it belonged to an adult. The creature was discovered in 1929 in a Belgian colonial museum, far from its lush African habitat. The bonobo is one of the last large mammals to be found by science. In the past two decades many strands of knowledge have come together concerning a relatively unknown ape with an unorthodox repertoire of behavior: the bonobo. Male-biased evolutionary scenarios-Man the Hunter, Man the Toolmaker and so on-are being challenged by the discovery that females play a central, perhaps even dominant, role in the social life of one of our nearest relatives.

At a juncture in history during which women are seeking equality with men, science arrives with a belated gift to the feminist movement.

Bonobo vs chimpanzee fight