Senegal's spear-wielding savannah chimps yield clues on humanity's past

The rare chimpanzees -- who live in the bush of hot, southeast Senegal rather than the forest as is more common -- exist on the extreme edge of what is possible for their species. Their unusual way of living offers clues into humans' own evolutionary past, while their adaptations to the heat appear timely in a world where temperatures are on the rise. Soaking in pools, cooling off in caves and even wielding spears: The 35 wild chimps of the Fongoli community have adapted to the environment with...