Homo erectus Infancy and Childhood The Turning Point in the Evolution of Behavioral Development in Hominids

The evolution of hominid behavioral ontogeny can be reconstructed using two lines of evidence: first, comparative neontological data on the behavior and development of living hominoid species (humans and the great apes), and second, comparative paleontological and archaeological evidence associated with fossil hominids. (Although behavior rarely fossilizes, it can leave significant traces.)1 In this chapter I focus on paleontological and neontological evidence relevant to modeling the evolution of the following hominid adaptations: (1) bipedal locomotion and stance; (2) tool use and tool making; (3) subsistence patterns; (4) growth and development and other life history patterns; (5) childbirth; (6) childhood and child care; and (7) cognition and cognitive development. In each case I present a cladistic model for the origins of the characters in question.2 Specifically, I review pertinent data on the following widely recognized hominid genera and species: Australopithecus species (A. afarensis, A. africanus, and A. robustus [Paranthropus robustus]), early Homo species (Australopithecus gahri, Homo habilis, and Homo rudolfensis), and Middle Pleistocene Homo species (Homo erectus, Homo ergaster, and others), which I am calling erectines.