Whale flippers contain five fingers and wrist bones

While a whale's flipper appears to be a solid paddle designed for steering through water, its internal anatomy reveals a surprising link to its terrestrial past. Beneath the flesh and blubber lies a skeletal structure nearly identical to a human hand, complete with five distinct fingers, a palm, and a complex wrist. These bones are the evolutionary remnants of the whale's ancestors, which were four legged mammals about the size of a large dog that walked on land fifty million years ago.