Pliohippus

Pliohippus, extinct genus of horses that inhabited North America during the Pliocene Epoch (5.3–2.6 million years ago). Pliohippus, the earliest one-toed horse, evolved from Merychippus, a three-toed horse of the preceding Miocene Epoch (23–5.3 million years ago). The teeth of Pliohippus are taller and more complexly folded than those of earlier horses; these features indicate a greater dependence on grazing than browsing for food. Because of its diet and its specializations for running, it is likely that Pliohippus lived on open plains.

This article was most recently revised and updated by Richard Pallardy.