The reduced hind limbs of whales are often touted as another example of vestigial structures, left over from their landlubbing days around 50 million years ago. Now, the legs are reduced to tiny ...

This story appears in the August 2010 issue of National Geographic magazine. Thirty-seven million years ago, in the waters of the prehistoric Tethys Ocean, a sinuous, 50-foot-long beast with ...

This five-metre-long animal had proper flippers and tiny hind legs. It lived entirely in the water and was a good swimmer. It also gave birth to its young underwater. The descendants of Dorudon went ...