The evolution of difficult birth in humans


Barbara Fischer

Unit for Theoretical Biology, Department of Evolutionary Biology
University of Vienna

Birth is remarkably difficult in humans, in comparison to the other great apes. In this talk, I will review why human birth evolved this way. To ease birth, humans evolved a sexually dimorphic pelvis with a wider pelvic canal in females, compared to males. I will present results on the variation in pelvic morphology in humans and some new evidence from a comparative study in humans and chimpanzees on the evolutionary origin of pelvic sex differences. Surprisingly, the latter results suggest that the pattern of pelvic sex differences did not evolve de novo in modern humans but that it is much older (likely of mammalian or amniote origin).