Neurobiology and the Evolution of Dolphins

Dolphins and other toothed whales seem to be perfectly adapted to their aquatic environment, and sometimes it is hard to believe that they originated from terrestrial mammals. Their ancestors were generalized (basic) four-legged terrestrial mammals at the origin of even-toed hoofed animals (artiodactyls) in the Paleogene (about 65 million years ago). Dolphins are most remarkable because of the way they accomplished such an extreme change of habitat. This transgression was correlated to a variety of modifications in the general mammalian bauplan as to morphological and physiological aspects of every organ system.