At a research site in Fongoli, Senegal, a female chimpanzee breaks off a branch, chews the end to make it sharp, and then uses this rudimentary spear to skewer a tasty bush baby hiding inside a hollow tree. It’s an astonishing breakthrough for primate researchers—the first time anyone has documented a chimpanzee wielding a carefully prepared, preplanned weapon. But it’s only the latest in a slew of extraordinary new findings about ape behavior.
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