BOB HIRSHON (host):
Big-brained babies. I’m Bob Hirshon and this is Science Update.
For our closest relatives, the great apes, giving birth is easy and painless.
So why is human childbirth so difficult and – until modern times – risky? University of Delaware biological anthropologist Karen Rosenberg says a narrow pelvis built for walking upright, along with an extraordinarily large brain are to blame for childbirth’s challenges. But to persist through time, this uncomfortable combinationmust be worth the trouble.
She says one factor that lowers the risk is our species’ unusual habit of giving birth with other people around.
And this is in really sharp contrast to the way that apes give birth. We think that’s because we benefit from having someone do a bunch of things to help the baby emerge from the birth canal that other animals can do for themselves, but humans can’t do for themselves.
I’m Bob Hirshon, for AAAS, the science society.