The Fin Whale is the second largest member of the whale family. It is named for the large dorsal fin that rises from its back. It is also one of the fastest swimmers of the great whales. They can swim 30 miles per hour. The first ancestors of whales lived more than fifty million years ago.
Scientists believe they are descended from creatures that lived on land, possibly the mesonychid.
At some point, they began to stay in the oceans. Their bodies became more streamlined for easier swimming. Their fur was replaced with blubber to keep them warm. Skeleton bones of whales today show clues of whales from a long time ago. Inside their flippers are bones like a hand.