The Change to Humanness
The change to humanness brought two bodily changes that affected birth and child care. These were head size and width of the pelvis. Walking upright produced a narrower pelvis to hold the guts in position. Yet as language developed, brains and hence heads grew much bigger relative to body size. To compensate, humans are born at an earlier stage of growth than apes. They are helpless longer and require longer and more total care. This in turn caused early women to concentrate more on child care and less on defense than do female apes.
Language made possible not only a division and cooperation in labor but also all forms of tradition, rules, morality, and cultural learning. Rules banning sex relations among close kinfolk must have come very early. Precisely how or why they developed is unknown, but they had at least two useful functions. They helped to preserve order in the family as a cooperative unit by outlawing competition for mates. They also created bonds between families, or even between separate bands, and so provided a basis for wider cooperation in the struggle for livelihood and the expansion of knowledge.
It is not clear when all these changes took place. Climatic change with increased drought began regionally up to 28 million years ago. The divergence between prehuman and gorilla-chimpanzees stems had occurred in both Africa and India at least 12 million years ago. The prehuman stem lead to the Australopithecenes of East and South Africa, about 1,750,000 years ago. These were pigmylike, two-footed, upright hominids with larger than ape brains, who made tools and probably hunted in savannah regions. It is unlikely that they knew the use of fire.
The first known use of fire is that of cave-dwelling hominids (Sinanthropus, a branch of the Pithecanthropines) at Choukoutien near Peking, some half a million years ago during the second ice age. Fire was used regularly in hearths, suggesting cookery, by the time of the Acheulean and Mousterian cultures of Neanderthal man in Europe, Africa, and Asia before, during, and after the third ice age, some 150,000 to 100,000 years ago. These people, too, were often cave dwellers and buried their dead ceremonially in caves. Cave dwelling by night as well as by day was probably, in fact, not safe for humans until fire came into use to drive away predators.
Most anthropologists conclude that home life, the family and language had developed by the time of Neanderthal man, who was closely similar and may have been ancestral to modern homo sapiens. Some anthropologists believe that the Australopithecenes already had language nearly 2 million years ago, while another thinks that language and incest prohibitions did not evolve until the time of homo sapiens some 70,000 to 50,000 years ago. It seems that family life built around tool use, the use of language, cookery, and a sexual division of labor must have been established sometime between about 500,000 and 200,000 years ago.
