This graphic from Evolution traces the evolution of whales from land-dwelling mammals to the aquatic creatures we know today. The evolution of whales has been a mystery. How did a large, big-brained mammal come to live entirely in water,when mammals evolved on land? The discovery of fossils with transitional features, explored in this PDF, documents the transformation of whales from land animals to ocean dwellers.
© 2015 PBS & WGBH Educational Foundation. All rights reserved.