Bipedal Human Ancestor 'Lucy' Was a Tree Climber, Too
"Lucy," an early human ancestor that lived 3 million years ago, walked on two legs. High-resolution computed X-ray tomography (CT) scans of long bones in Lucy's arms reveal internal structures suggesting that her upper limbs were built for heavy load bearing — much like chimpanzees' arms, which they use to pull themselves up tree trunks and to swing between branches. This adds to a growing body of evidence that although Lucy's pelvis, leg bones and feet supported bipedal walking, her upper body was adapted for at least partial life in trees — far more so than in modern humans.
