Wide pelvises of ancient humans allowed bigger brains

William Atkins
Monday, 01 December 2008 21:20

Science - Biology

H. erectus is thought to have been the first hominin (a group comprising of humans, chimpanzees, and their ancestors) to move outside of Africa, possibly around two million years ago, during the early Pleistsocene period.

Their paper went on to state, “This obstetrically capacious pelvis demonstrates that pelvic shape in H. erectus was evolving in response to increasing fetal brain size."

And, "This pelvis indicates that neither adaptations to tropical environments nor endurance running were primary selective factors in determining pelvis morphology in H. erectus during the early Pleistocene.”

The widening hips of female H. erectus began as far back as 1.2 million years ago, according to the Simpson-led team.

Their paper states that past studies have indicated H. erectus had narrow hips and tall height because it allowed them to hunt more efficiently—being able to run faster.

However, this study states that wider pelvises would be preferred over more narrow ones because it allows for larger brains to develop.

The fossils they found do not show narrow hips, at least, with female H. erectus.

Although not stated in the study, maybe male H. erectus maintained narrow hips for faster running during hunting, and female H. erectus evolved wider hips for child birth, similar to what we see today in modern males and females.