New research published in Science Advances has fundamentally challenged the long-standing perception of bonobos as peaceful primates. Contrary to their historical reputation as the more harmonious cousins of chimpanzees, a comprehensive study reveals that bonobos demonstrate comparable levels of aggression, with a distinct pattern of directing hostility primarily towards males.
European researchers conducted an extensive behavioral analysis across 22 primate groups—13 bonobo and 9 chimpanzee communities—in zoo environments. The study meticulously measured various aggressive behaviors, encompassing both physical acts (biting, slapping) and non-physical demonstrations (object throwing, intimidation). The findings revealed no significant overall difference in absolute aggression rates between the two species.
The critical distinction emerged in the distribution of aggression. While chimpanzees in patriarchal societies exhibit aggression primarily from males directed at both sexes, bonobos in matriarchal systems display equal aggression levels from both sexes that is predominantly targeted at males. This male-directed aggression in bonobo society presents a particular paradox, as researchers expected greater competition and hostility among females who dominate these social structures.
Co-author Nicky Staes noted that the findings challenge simplistic species classifications, while Emile Bryon suggested possible explanations for this unexpected dynamic. The well-documented bonobo practice of using sexual activity to diffuse tension might reduce female-female conflict. Alternatively, aggression may be strategically redirected toward males, who effectively become buffers in female competitive dynamics.
The study acknowledges limitations regarding captive observation environments where food scarcity—a major tension source—is absent. However, researchers highlighted significant behavioral variability across different groups of both species, suggesting that understanding primate aggression requires moving beyond broad generalizations to appreciate complex social adaptations.