We may share a common ancestor with chimpanzees, but somewhere along the evolutionary line to us, our brains took a major detour. New research suggests that chimpanzees can rationally weigh evidence, a trait that used to be thought as uniquely human.

PLUS:

• Why penguin-eating pumas live closer together in Patagonia
• Ants sacrifice the strength of individual workers for quantity
• Mapping the landmass beneath Antarctica's massive ice sheet
• How deep sea ocean environments affect fish body shape