The origins of the horse go back to eohippus the "dawn horse" of me Eocene only 10 to 20 inches tall. Like its relatives the ancient tapir and rhinoceros, eohippus had four toes on its front feet, three on the rear, and teeth adapted to a forest diet of soft leaves. Eohippus died out about 5.1 million years ago in both North America and Europe.

Late ancestral horse types moved from their forest niche out onto the grassy plains. Their teeth ac to accommodate to hard siliceous grass. No longer could these protohorses slip away through thick forest when dancer threatened. Escape now demanded speed and endurance Limbs crew longer. Extra toes became vestiges that were not visible externally