“Do you think whales ever walked the earth?”I thought the captain of a whale watch boat in Monterey Bay was asking a trick question.  But it’s no riddle—it’s a scientifically documented, evolutionary fact.

The largest creatures on the planet, whales are classified, along with dolphins and porpoises, as cetaceans, from an ancient Greek word for sea monster.  However, they descended from rather humble four-legged mammals that hunted and fished along the riverbanks of what is now Pakistan and India.

In one of evolution’s most dramatic U-turns, these land dwellers returned to the ocean from which their ancestors had emerged. In a geological blink—roughly 10 million years—they reshaped their bodies for an aquatic life. Fur thinned. Limbs flattened. Tails strengthened.  Nostrils began their slow migration to the top of the head. Hooves gave way to flukes