In order to accommodate the shift that allows human women to walk upright, their bodies have undergone a gradual evolutionary change that leaves their pelvises roughly 30% smaller than those of their homo erectus ancestors. The size of infants brains and the heads that house them have, in that time, gotten larger, according to studies conducted by paleoanthropologists at the University of Indiana. The resulting shift means that, in order to walk upright, women’s bodies simply cannot … [Read more...]