The Left Bank Ape

The Left Bank Ape
An exclusive look at bonobos
By David Quammen
Photograph by Christian Ziegler
In a remote forest sector of the Democratic Republic of the Congo, along the north bank of the Luo River, 50 miles by dirt trail from the nearest grass airstrip, lies the Wamba research camp, a place that’s quietly renowned in the annals of primatology. Wamba was founded in 1974 by a Japaneseprimatologist named Takayoshi Kano for the study of the bonobo, Pan paniscus, a species of simian unlike any other.
The bonobo, in case you haven’t heard, carries a reputation as the “make love, not war” member of the ape lineage, far lustier and less bellicose than its close cousin, the chimpanzee. Modern studies of zoo populations by the Dutch-American biologist Frans de Waal and others havedocumented its easy, pervasive sexuality and its propensity for amicable bonding (especially among females), in contrast with chimpanzee dominance battles (especially among males) and intergroup warfare. But the bonobo’s behavior in the wild has been harder to know, and Takayoshi Kano, operating out of the Primate Research Institute of Kyoto University, was among the first scientists aspiring to study itthere. Apart from several interruptions, including a hiatus during the Congo wars of 1996-2002, observations at Wamba have continued ever since.
Early one morning I followed a researcher named Tetsuya Sakamaki, also from Kyoto University, into the forest. Promptly I saw things that, according to the popular image of the species, I might not have expected. Bonobos quarreled. They hunted for meat.They went hours at a stretch without having sex. This was the animal so renowned for its lubricious, pacific social life?
As Sakamaki and I watched a party of bonobos feeding on the fruits of a boleka tree—small, grapelike morsels with papery husks—he identified the individuals by name. That female there, with the sexual swelling, we call her Nova, he said. She last gave birth in 2008; the gaudyinflation of her genital area, like a pink sofa cushion taped to her rump, advertised her readiness to breed again. This female is Nao, he said, very old, very senior. Nao has two daughters, of which the elder has so far remained in this group. And that female there, that’s Kiku, also very senior, with three sons in the group. One of those sons is Nobita—easy to identify, Sakamaki explained, byhis great size and the digits missing from his right hand and both feet and by the blackness of his testes. Missing digits suggest a mishap in a snare, not unusual for bonobos facing the hazards of human proximity. Nobita seems to be the alpha male, insofar as bonobo groups recognize alpha males.
By now we had followed the bonobos into a grove of musanga trees, and they were stuffing their mouthswith fruit, pulpy and green. Suddenly a screechy altercation broke out between Nobita and another male, Jiro. Kiku, Nobita’s elderly mother, charged over to support her son. Cowed by the two of them, Jiro retreated. He sulked in a nearby tree. It’s interesting, Sakamaki noted, that Nobita is the largest male in this group, and yet his mother helps him in a fight. Even a high-ranking adult malesuch as Nobita seems to hold his status partly on the merits of his mama.
Forty minutes later, when the screeching began again, Sakamaki drew my attention to the focus of excitement: an anomalure (a gliding rodent, like a flying squirrel), scrambling for its life on a tree trunk while several bonobos converged around it. As the bonobos came closer, the anomalure launched itself into space and glidedaway. Then we noticed a second one, clinging secretively to the east side of another large bole while a bonobo named Jeudi sat clueless just 15 feet to the west. This anomalure, pink eared and pale eyed, held its place on the bark more patiently, frozen, not giving itself away. Within a moment, though, other bonobos spotted it, and the group closed in, shrieking with predatory menace. One...