Pakicetus. Illustration and photo-reconstruction of the whale ancestor Pakicetus. Pakicetus is a genus of extinct predatory mammal that belonged to the suborder Achaeoceti. It is the most ancient of presently-known direct ancestors of modern-day whales. It lived approximately 48 million years ago and adjusted to searching for food under water. It was endemic to the territory of present-day Pakistan. This prehistoric whale remained semi-aquatic as the modern-day otter. Its ear started to adapt to hearing underwater but still could not endure high pressure. It had massive jaws revealing its predatory nature, closely set eyes, and a muscular tail. Its sharp teeth were suited to grasping slimy fish. Its exterior was reminiscent of that of a dog, but with hooves and a thin tail. It probably had webbed toes. Its main peculiarity was that its malleolar bones were similar to those of pigs, sheep and hippos. Its skull on the other hand was very similar to those of whales.