Species: Indohyus indirae
Location: Kashmir, India
Age: Middle Eocene; 48 million years ago
Indohyus belongs to an early radiation of artiodactyl mammals called raoellids, archaic even-toed hoofed mammals known mostly from teeth and found only in Eocene southern Asia. Indohyus is known from a partially-complete skeleton, which reveals peculiar features. It is about the size of a fox with heavy leg bones. These features are largely used by limbed mammals that spend time in water, using the heavy legs to weigh down the animal to counteract natural boyancy. This means Indohyus could live a life not unlike that of a modern water mousedeer, diving underwater to escape predators or to eat water plants. Its most interesting feature of all is its ear contains a large bone surrounding its middle ear, a feature seen only in whales. The same feature also appears in Pakicetus as well. The presence of an encased middle ear in an artiodactyl shows further evidence of whales being descendents of land-based hoofed mammals like pigs and antelope. However because it existed after many early whales are known, Indohyus could not be an ancestor of whales but it could share an ancestor with them.