Whales give our planet’s oceans heartbeats, songs, the birth of young and scenes of pure joy.

In our imaginations, nothing symbolizes our seas more than whales. These bigger-than-life creatures imbue our oceans with life, with song and with majesty, mystery and myth. If anything else represents our oceans more, I can’t think of it.

That thought is a bit ironic because there was a time when whales walked the Earth. These early cetacean ancestors later chose the sea, however; leaving us and terra firma behind.

The transformation of a four-legged land mammal into an animal completely adapted to marine life took hardly any time at all in evolutionary terms. ©From the video “When Whales Walked,” PBS Digital Studios

According to the PBS Digital Studios video you’re about to watch, the tale of whale evolution is a story about one of the most remarkable transitions in history. The whales we know today arose from tiny, four-legged plant-eaters no bigger than house cats to the modern seafaring giants. And that change was dramatic and fast: it took less than 20 million years—about the evolutionary equivalent of a lunch break—for this entire, astonishing transformation to occur.

Whales’ land-dwelling predecessors lived about 50 million years ago and are thought to be part of the scientific order Mesonychia (scientific family Mesonychidae), extinct mammals that sometimes would feast on fish at river edges. As time went on and the opportunities for finding food in the waters seemed to increase for these animals, they evolved to take advantage of their new environment. These physical improvements included better hearing systems for underwater communications and navigation, and completely new ways of locomotion—first as amphibians and then later as fully developed marine mammals. Today’s whales are actually most closely related to the scientific order Artiodactyla: hoofed animals, which include deer, hippos and pigs.


Whales eventually reclaimed a place in the sea; and I, for one, am glad they did.

This story of evolution is a fascinating whale tale. Learn more about it by viewing the PBS Eons video below, which was produced in conjunction with The Great Courses Plus.

I, for one, am thankful that long ago, some cute, little beings decided to leave the land for lives spent in the sea. Without them, I think, there’d be a leviathan loss to our planet’s melodious music, marine magnificence and magical myths.

Here’s to finding your true places and natural habitats,