uncovered two human ancestors who each provide invaluable insight on humans' evolution from tree climbers to upright walkers. At 4.4 million years old, Ardi, short for Ardipithecus ramidus, is mankind ...

and Zeresenay Alemseged at California Academy of Sciences in San Francisco, Calif. was titled, "Australopithecus afarensis Scapular Ontogeny, Function, and the Role of Climbing in Human Evolution." ...

Their analysis placed the tree-climbing, upright-walking specimen into an evolutionary bracket between the unidentified common human-ape ancestor and the line that led to modern homo sapiens.

Sleeping. It’s a large part of our lives and an essential function that enables our bodies and minds to recharge. While this universal human experience may seem like a biological constant ...

Humans' ancestors started off with a tail, but about 25 million years ago, they dropped the appendage, leaving it to other tree-dwelling primates like monkeys. But it's not like we've completely ...

Our ancestors still resembled apes ... long arms that suggest she spent a lot of time in trees. But she also walked on two legs, like modern humans. Receive a weekly dose of discovery in your ...