This adaptation enabled the human brain to continue to grow, but it imposed a new discipline. It is to be noted that traditional claims about men's and women's gender roles have been challenged in the past years. New findings from 9000 BP graves in Peru indicated that biological women hunted nearly as often as males and wife stealing was not exclusive inter-gender usage. In 30 to 50 per cent of cases it was husband stealing. Regardless, humans' increasingly sedentary lifestyle to protect their more vulnerable offspring led them to grow even more dependent on tool-making to compete with other animals and other humans, and rely less on body size and strength.
