Some chimpanzees in West Africa repeatedly throw rocks at particular trees, creating piles of stones that can remain in use for more than a decade. Researchers think this unusual behavior may be cultural and could serve as a form of communication, territorial signaling, or something more symbolic. Camera traps and audio recordings are now being used to reveal who throws the stones and how nearby chimpanzees respond.
why not game? Practice for either hunting or tribal warfare.
Yah, surprising how often “it’s fun” gets overlooked as a solution academically. Odds on it being a juvenile behaviour.