According to a new study, chimpanzees, like humans, must contend with a confined bony birth canal when giving birth. In humans, the problem was exacerbated by our unique form of upright walking since ...

Add Yahoo as a preferred source to see more of our stories on Google. New research finds some small primates face birth canal constraints as severe as, or greater than, those seen in humans. (CREDIT: ...

3D simulation of the birth canal of chimpanzees with (B) the fetal head in a fully extended position, the typical head alignment in apes, and (C) the fetal head in a fully flexed position, the usual ...

For decades, one idea has shaped discussions about human evolution and birth: humans endure unusually difficult childbirth because large-brained babies must pass through a relatively narrow pelvis ...