Where & When? Fossils of Hyracotherium are found at many Eocene localities in the western US and Europe. Species in this genus lived from 55 - 45 million years ago.

A MONKEY?
Why was Hyracotherium once thought to be a monkey?

The teeth of these horses are quite primitive, like those of monkeys and other primates (e.g. humans!). The great 19th century British anatomist, Richard Owen, initially thought that this animal proved that primates once lived in England. He corrected his mistake after studying more specimens.

Hyracotherium is now believed to be a primitive horse, the earliest-known member of the family Equidae. It lived in both the Old World and in North America. Specimens found in the United States were initially given the name "eohippus" by O. Marsh in 1876. Paleontologists later determined that eohippus was really the same genus as Hyracotherium and based on scientific procedure, the older name Hyracotherium (1840) takes precedence over, and includes, eohippus (1876).