Like Pakicetus, it spent time both in and out of water, but its large feet looked more like flippers than its ancestor's longer legs. It also used its tail for swimming. An artist's impression of ...

You can see the humpback's characteristic long, knobbly pectoral flippers beginning to grow larger. A humpback whale's gestation period is about 11 months. Although this foetus would have remained in ...

It's the tale of an ancient land mammal making its way back to the sea, becoming the forerunner of today's whales ... propelled by its sturdy flippers and long, flexible body.

Recording the whale’s heartbeat was not an easy feat. It required attaching electrodes sitting atop suction cups to the behemoth’s body at exactly the right spot—just behind the left flipper. “To be ...

At birth, beluga whales are 5 feet long, roughly 100 pounds, and dark blue-gray in color. Unmistakable as adults, their color lightens to white, and they have a dorsal ridge rather than a fin. Belugas ...