Fossils dating back about 2 million years have been found with brain capacities much larger than any Australopithecus xfossil. On the basis of brain size, these fossils are named Homo habilis. Homo habilis is regarded as the first human and the first species of the genus Homo. Homo habilis means “handy human.” Members of this species were apparently able to use tools, build shelters, and fashion protective clothing. Members of the species appear to have spent much time in trees as well as on the ground, and to have walked erect on two legs. Homo habilis is thought to have been the predominant species during the Stone Age, a time during which humans fashioned stone tools. Homo habilis eventually became extinct, presumably about 35,000 years ago.