Bonobos and chimpanzees: revisiting the aggression dichotomy

Aggression in the genus Pan (including bonobos and chimpanzees) remains a central puzzle in primatology and anthropology. Traditionally framed as a dichotomy between “peaceful bonobos” and “violent chimpanzees,” recent findings challenge this view by documenting coalitionary aggression, maternal cannibalism, and lethal intergroup encounters in bonobos, alongside evidence that captive chimpanzees and bonobos exhibit comparable aggression levels. These observations highlight the importance of ecological context, demographic composition, and behavioral plasticity in shaping aggression. We propose that species identity is a weaker predictor of aggression in Pan than socioecological, demographic, social, and neuroendocrine context. While captivity offers methodological control, it also introduces confounds such as reduced group size, absence of fission–fusion dynamics, and enforced proximity. Conversely, wild studies reveal the ecological pressures, territorial defense, resource distribution, and interspecies competition that drive variation in aggression. Future research must integrate captive and free‑ranging data through hybrid protocols, quantify ecological and demographic drivers, and explore neuroendocrine mechanisms underlying sex‑specific aggression. An integrative review on Pan aggression will refine our understanding of adaptive strategies, illuminate the evolutionary roots of human social conflict, and advance comparative models of primate behavior.