Martin Surbeck and Gottfried Hohmann report in Current Biology that bonobos hunt monkeys, like chimpanzees.
It has been suggested bonobos do not hunt monkeys because aggression was selected against when ecological conditions favored female gregariousness and alliance formation . An alternative view is that insufficient data from multiple bonobo populations, incomplete habituation, and effects of human interference precluded observation of monkey hunting . While more data are required before conclusions can be drawn about the relationship between social traits and hunting behavior, our data raise other questions: Do the observed cases present a novel behavior? What are the environmental and social factors promoting hunting and meat eating at LuiKotale?
So far, evidence for hunting and meat eating by bonobos has largely been based on fresh fecal samples . Only one sample contained the digit of a black mangabey, Cercocebus aterrhimus, but it was not entirely clear if bonobos had hunted the mangabey themselves, or whether they had taken it from another predator. In both Pan species, hunting of mammalian prey is relatively rare and its detection requires frequent, close-range observations. Field studies in the Ta Forest (Ivory Coast) have accumulated one of the largest data sets on monkey hunting by chimpanzees, but it took years before researchers were able to directly observe monkey killing . We tend to believe that improved habituation made our observations possible (rather than the behavior being novel) (Surbeck and Hohmann 2008:R906-R907).
The authors go on to speculate that hunting may be subject to traditional variation in bonobos, since at other field sites the bonobos interact in different ways with monkey species, ranging to mutual grooming. But in their observations, they have five hunts with three successful captures; two of the three individuals who caught monkeys were females.
Surbeck M, Hohmann G. 2008. Primate hunting by bonobos at LuiKotale, Salonga National Park. Curr Biol 18:R906-R907. doi:10.1016/j.cub.2008.08.040