As air-breathing mammals, whales must once have lived on land and needed hind limbs capable of supporting the mammals' weight  Whales have the bare remnants of a pelvis  If animals have a pelvis, we expect them to have hind limbs  A newly discovered fossilized whale skeleton has very fragile hind limbs that could not have supported the animal' s weight on land
This skeleton had a partial pelvis
Scientists are uncertain whether the apparently nonfunctioning limbs of other early mammals derived from once-functioning limbs of their ancestors.