One of the earliest species of the genus Homo to be discovered is Homo habilis, which basically means “handy man.” The name comes from the belief at the time of its discovery that this species was the first to start using stone tools. The first fossils to be uncovered in Olduvai Gorge were from the same stratigraphic layer as simple stone tools. Fossils of the crania and postcranial skeleton for this species have been found in both eastern and southern Africa and date to around 2.5–1.6 million years ago.
Given the gradual changes that take place in evolution, Homo habilis shares a number of characteristics that are similar to the genus Australopithecus, such as in the postcranial elements. That said, the size and shape of the Homo habilis skull are markedly different. The size of the brain is much larger relative to the size of the body, being around 680 cc. In order to house a larger brain, the skull features a more vertical frontal bone, creating a more vertical forehead. The brow ridges that sit on the lower portion of the frontal bone are also reduced in size. Other reductions in the face include reduced prognathism and a reduction in the size of the premolars and molars.
Postcranial elements display clear signs of bipedalism, such as the large toe being in line with the other toes instead being off to the side as they are in modern apes. Furthermore, the arches of the foot are present, allowing the full weight of the body to be supported and act as a shock absorber when walking. The leg bones are also longer than in Australopithecus, but Homo habilis retained long arms. Other primitive features include hand and finger bones that would have made climbing in the trees easier. The robustness of the finger bones is more comparable to those of modern apes than humans.
