Whales get a second life as deep-sea buffets
How can whales evolve back to becoming land animals? - Quora
What evidence is there that the ancestors of whales walked on land? - Quora
The evolution of whales from land to sea
Dolphins and whales separately evolved the same speedy swimming bones
Voices in the Ocean: A Journey into the Wild and Haunting World of Dolphins , Casey, Susan
During the evolution of whales and dolphins, would they have become land animals and then returned to the sea? - Quora
What Whales and Dolphins Left Behind for Life in the Ocean - The New York Times
Ichthyosaur: Apex predator of the dinosaur-era seas