Why Do Whales Have Hip Bones?

Both whales and dolphins have pelvic (hip) bones, evolutionary remnants from when their ancestors walked on land more than 40 million years ago. Common wisdom has long held that those bones are simply vestigial, slowly withering away like tailbones on humans.

Why do whales have hips and legs?

Some 54 million years ago, the ancestors of whales and dolphins were four-legged mammals. Their anatomy was well-adapted for moving around on land, including their hips. ... Those firm connections allowed the animal to hold its body up against gravity, and use the forces generated by its legs to propel its body forward.

Why do whales have bones for an unused hip and pelvis?

Hips don't lie: Whale pelvic bones are not vestigial but instead evolved to help the marine mammals maneuver better during sex. Whales have especially small pelvic bones compared to their body size.