National Geographic News, Reporting Your World Daily

Thursday, August 28, 2008

Photo: Why Pregnant Women Don't Tip Over


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A pregnant australopithecine, an early human ancestor, displays the leaned-back posture adopted by human women to help them support the load of their developing babies, as seen in an artist's conception.

A new study shows that three wedge-shaped vertebrae in women's lower backs evolved to allow pregnant females to take this posture without damaging their spines.

Australopithecine illustration courtesy John Gurche; human-chimp spine comparison © Nature