ABSTRACT
Human beings are the only remaining bipedal hominids to walk the surface of the Earth. The upright posture and bipedal gait that characterize modern man have a long evolutionary history. In Laetoli, East Africa there is a set of fossilized footprints that it is thought to have been made 3.7 million years ago by early hominids known as Australopithecus afarensis. Reconstruction of the walking patterns from the footprints, using data on modern human gait, indicates that Australopithecus was fully bipedal. According to anthropologists such as Lovejoy (1988), Australopithecus had a cranial capacity similar to that of a modern chimpanzee and weighed ~30 kg, but its pelvis, femur and lumbar spine resembled those of modern man. Both the human and the australopithecine bones are very different from those of a chimpanzee. The former are adapted to enable the animal to walk on two legs rather than four and to stand upright with the weight of the upper body balanced on top of the bones of the spine, pelvis and femur.
