Three upright walkers, including Lucy (center) and two specimens of Australopithecus sediba , a human ancestor from South Africa dating back nearly 2 million years.
Image compiled by Peter Schmid and courtesy of Lee R. Berger/Wikimedia Commons
Walking has taken a very long time to develop, with evidence of bipedalism among early humans in Africa roughly 4.4 million years ago.
This skull, found in France, was among the first fossils to be recognized as belonging to our own species.
DEA /G. Cigolini via Getty Images
Our biggest evolutionary advantages are an ability to walk on two legs and our big brains.
Chuang Zhao
Bipedal movement has existed in modern reptiles for much longer than we previously knew.
Chimpanzees are wily enough to adapt in some ways when people encroach on their turf.
Kimberley Hockings
Apes and people are sharing habitat more than ever. As apes are pushed into novel situations, we can see how they adapt and maybe find clues into early human evolution.