Fast forward to 40-33 million years ago, and we meet Dorudon, a five-meter-long, fully aquatic whale. Dorudon had flippers, tiny hind legs, and even gave birth underwater. By this point ...

As time passed, the species evolved further, and by 40 to 33 million years ago, the fully aquatic Dorudon emerged. Dorudon was a five-metre-long creature with flippers and tiny hind legs ...