Female coalitions against male aggression in wild chimpanzees of the Budongo Forest

In the wild, female chimpanzees (Pan troglodytes) are subject to male aggression that at times can be prolonged or particularly violent. Cooperatively retaliating to such aggression, a strategy observed in the con-generic Pan paniscus, has not been reported from the wild despite more than four decades of detailed behavioral study across a number of populations and reports of such behavior among captive female chimpanzees. If the reports from captivity represent an inherent capacity, then the absence of similar reports from wild populations suggests that female may only be able to form coalitions under appropriate ecological and demographic conditions. During a study of aggression of male and female aggressive interactions among chimpanzees of the Budongo Forest, Uganda, wild adult female chimpanzees sometimes formed coalitions with one-another to retaliate against male aggression. This may be possible because these females tend to be more gregarious than those in other populations of East African chimpanzees, as has been suggested by other studies of the same population. These observations suggest that the extent and variation of female chimpanzee social strategies need reconsideration, and strengthens the argument that at least some of the differences between chimpanzees and bonobos may be more of degree than of kind.