Researchers investigating the evolution of human aggression look to our closest living relatives, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), as valuable sources of comparative data.

Highlights

•Kokolopori bonobos show higher rates of male-male aggression than Gombe chimpanzees

•Those results remain true when limiting analyses to contact aggression

•In both populations, more aggressive males obtained higher mating success

•Male chimpanzees form more coalitions than male bonobos