Add another thing to the already long list of what chimps do (like using a hammer to crack nuts): using spears to hunt other primates:
Researchers documented 22 cases of chimps fashioning tools to jab at smaller primates sheltering in cavities of hollow branches or tree trunks.
The report's authors, Jill Pruetz and Paco Bertolani, said the finding could have implications for human evolution.
(Although I could be worng)