Merychippus represents a milestone in the evolution of horses. Though it retained the primitive character of 3 toes, it looked like a modern horse. Merychippus had a long face. Its long legs allowed it to escape from predators and migrate long distances to feed. It had high-crowned cheek teeth, making it the first known grazing horse and the ancestor of all later horse lineages. Fossils ofMerychippus are found at many late Miocene localities throughout the United States. Species in this genus lived from 17-11 million years ago.