Basilosaurus, an Ancient Whale
About thirty-five to forty million years ago, Eocene
Hanging beside the right whale is a very different animal: a long, snake-like skeleton with a narrow skull full of sharp teeth and a body that seems to go on forever. This is Basilosaurus, a whale that lived about thirty-seven million years ago in warm seas that then covered what is now the southern United States. The name means king lizard, because the scientist who first described it in the 1830s mistook the bones for those of a giant sea reptile. It was in fact one of the first fully aquatic whales, an early member of the group that eventually gave rise to both the whales with teeth and the whales with baleen.
Look first at the head. The teeth at the front are pointed for catching fish and the ones at the back have serrated edges for slicing, quite unlike the baleen of the whale next door. Then follow the spine back: the vertebrae are unusually long, which gave the animal its eel-like proportions and probably meant it swam with a sinuous, undulating motion. Near the end of the body, on the underside, are tiny hind legs with knees and toes, only a few inches long and useless for walking. They are among the clearest evidence in any museum that whales descended from land animals.
Many of the bones come from Alabama, where Basilosaurus fossils were so common in the nineteenth century that farmers used the vertebrae as fence posts and andirons, and the state made it its official fossil. The pairing with Phoenix was a deliberate choice by the curators: one animal from the dawn of whales and one from a species that may not survive this century, hanging together as the beginning and the possible end of a story. Notice the shape of the skull, which has no room for the fatty melon that modern whales use for echolocation, so this animal hunted by sight.
Did You Know? Basilosaurus bones were so common in Alabama that nineteenth-century farmers used the vertebrae as fence posts.
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