The number of bones varies from one species of whale to another and is dependent, in part, on the length of the whale's spine. Sperm whales contain 164 bones, while the blue whale, the largest animal on earth, has 356 bones.
A whale's skeleton contains a skull, a spine and a rib cage, plus the bones that make up its flippers. The skeleton inside a whale's flipper looks like a version of a human hand; containing a shoulder, upper arm bone, lower arm bones, wrist bones and phalanges, or finger-type bones. Whales also contain several small bones floating down toward their tails. Scientists believe these are vestigial remnants of what were once hind legs.