Wild chimpanzees maintain stone-throwing ritual at specific trees for years
Researchers observed western chimpanzees in Guinea-Bissau repeatedly throwing rocks at particular trees, with some sites used for over a decade. The behavior, often accompanied by pant hoots and buttress drumming, may be a cultural display. Camera traps and audio recordings are being used to study the social context and responses.
The behavior has been documented in only four chimpanzee communities across West Africa, and its patchy distribution suggests cultural transmission rather than environmental necessity. Because the Boé chimpanzees remain unhabituated to human observers, researchers relied on camera traps and audio recorders to capture the stone-throwing events, which are typically performed by adult males.
The research team established a bush camp 22 kilometers from the village of Béli, working alongside local field assistants and a graduate student from the Great Ape Behaviour Lab. Scientists hope the behavior, which combines pant hoots, buttress drumming, and stone manipulation, may illuminate evolutionary links between primate communication and early human tool use.
This research could reshape public understanding of animal culture and cognition, suggesting that chimpanzees engage in symbolic or ritualistic behaviors previously considered uniquely human. Conservation efforts may benefit if heightened public interest translates into support for protecting West African chimpanzee habitats. The findings could also inform debates about the evolutionary origins of human communication and ritual practice, though interpretations remain speculative until broader social context is established.