Large heads, narrow pelvises and difficult childbirth in humans: Adaptations in human morphology explain why in new study
The size of the neonatal skull is large relative to the dimensions of the birth canal in the female pelvis. This is the reason why childbirth is slower and more difficult in humans than in most other primates. Scientists from the Universities of Oslo and Vienna, identified adaptations in the morphology of the human body, which were unknown so far. The results of this new study appeared in the current edition of Proceedings of the National Academy of Sciences. Proceedings of the National Academy of Sciences In hominids, upright walking evolved 4-5 million years ago. The human pelvis was affected by these changes and evolved accordingly to better serve the new pattern of movement. Later, after bipedal movement had long become obligatory, brains evolved to increasingly larger volumes. With that change, the head size of neonates also increased. The growing heads, however, had to be delivered through pelvises that were earlier adapted to upright walking. This is the reason for the l...