Neanderthals babies didn't do the twist





Giving birth is more difficult - and dangerous - for modern humans than for any other primate. Not only do human mothers have to push out babies with unusually big heads, but infants also have to rotate to fit their heads through the narrow birth canal. Now, a new virtual reconstruction of the pelvis of a Neanderthal woman suggests that Neanderthal mothers also had a tough time giving birth to their big-headed infants - but the babies, at least, didn't have to rotate to get out.

Paleoanthropologist Timothy Weaver of the University of California, Davis, thought the shift to this more complicated rotational birth predated the split between modern humans and Neanderthals. That's because Neanderthals, which lived until 30,000 years ago in Europe, also had big heads and, presumably, used the same evolutionary strategy to deliver their big-brained babies. But it has been difficult to test this idea. The only known female pelvis of a Neanderthal, discovered in Tabun (Israel), is fragmentary.
Collaborating with Jean-Jacques Hublin at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Weaver got permission to make computed tomography-scans of the pelvis. The two researchers were able to refit the pieces of the pubis, ischium, and ilium together in a three-dimensional, virtual reconstruction. They also used landmarks on the pelvic fragments to compare the pelvis to those of modern humans - and to predict the size and shape of the missing pieces, such as the sacrum and dimensions of the pelvic outlet.

The reconstruction suggests that the pelvis of the Tabun Neanderthal was widest from side to side all the way down the birth canal, more like that of Homo erectus or australopithecines than modern humans. And that means that although Neanderthal mothers still had difficult births because of their babies' large heads, their babies did not rotate in the womb, the team reported in the Proceedings of the National Academy of Sciences. ...

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