Chimpanzees are known to form bands to hunt and kill other primates, including monkeys. But bonobos, another primate closely related to humans and chimps, were thought to be confine their hunting to forest antelopes, squirrels and rodents.
Not so, a new study finds.
In the Oct. 14 issue of the journal Current Biology, researchers report the first direct evidence of wild bonobos hunting and eating the young of other primate species. The finding is part of a five-year study of the creatures in LuiKotale, Salonga National Park, in the Democratic Republic of Congo.
"These findings are particularly relevant for the discussion about male dominance and bonding, aggression and hunting — a domain that was thought to separate chimpanzees and bonobos," said Gottfried Hohmann of the Max Planck Institute for Evolutionary Anthropology. "In chimpanzees, male-dominance is associated with physical violence, hunting and meat consumption. By inference, the lack of male dominance and physical violence is often used to explain the relative absence of hunting and meat-eating in bonobos. Our observations suggest that, in contrast to previous assumptions, these behaviors may persist in societies with different social relations."
Bonobos live only in the lowland forest south of the Congo River, and, along with chimpanzees, they are humans' closest relatives.
Bonobos are perhaps best known for their promiscuity: sexual acts both within and between the sexes are a common means of greeting, resolving conflicts, or reconciling after conflicts.
The researchers have seen three instances of successful hunts in which bonobos captured and ate their primate prey. In two other cases, the bonobo hunting attempts failed. The data from LuiKotale showed that both bonobo sexes play active roles in pursuing and hunting monkeys. The involvement of adult females in the hunts (which is not seen in chimps) may reflect social patterns such as alliance formation and cooperation among adult females, they said.
The discovery challenges the theory that male dominance and aggression must be causally linked to hunting behavior, an idea held by earlier models of the evolution of aggression in human and non-human primates.