-
Pakicetus
If you happened to stumble across the small, dog-sized Pakicetus 50 million years ago, you'd never have guessed that its descendants would one day include giant sperm whales and gray whales. As far as paleontologists can tell, this was the earliest of all the prehistoric whales, a tiny, terrestrial, four-footed mammal that ventured only occasionally into the water to nab fish (we know that Pakicetus was largely landbound because its ears weren't well adapted to hearing well underwater). -
Ambulocetus
Ambulocetus dates from the era when the ancestors of modern whales were just dipping their toes into the water: this long, slender, otter-like mammal was built for an amphibious lifestyle, with webbed, padded feet and a narrow, crocodile-like snout. -
Rodhocetus
Evolve the dog-like whale ancestor Pakicetus a few million years, and you'll wind up with something like Rodhocetus: a larger, more streamlined mammal that spent most of its time in the water rather than on land (though its splay-footed posture demonsrates that it was capable of walking, or at least dragging itself along on solid ground). -
Basilosaurus
One of the odd things about paleontology is that incorrect names can sometimes take precedence over correct ones. For example, when its bones were first discovered in 1843, the prehistoric whale Basilosaurus was incorrectly identified as a marine reptile--hence its name, Greek for "king lizard." -
Dorudon
For years, experts believed that the prehistoric whale Dorudon was actually a juvenile Basilosaurus, the largest whale that ever lived. Then, the unexpected discovery of juvenile Dorudon fossils demonstrated conclusively that this short, stubby cetacean merited its own genus--and may actually have been preyed on by the occasional hungry Basilosaurus.
