Eohippus or Hyracotherium – Extinct Equidae

The Eohippus is one of the earliest equidae species and roamed North America & western Europe during the early to middle Eocene era (about 55 – 45 million years ago). They were about 2 feet long and weighed around 50 pounds.


This dog-sized creature was first described in 1841 by English paleontologist Richard Owen. Mr. Owen mistook them for a hyrax ancestor and called them Hyracotherium. Later in 1876 an American paleontologist named Othniel C. Marsh found a complete skeleton and created a new genus for it Eohippus (or ‘dawn horse’). When it was discovered that these two animals were, in fact one species the two names became essentially synonymous.

Eohippus Skeleton

Image from Jeff Kubina

Not only dog-like in size, these tiny horses had four toes on their front and three toes on their back feet.

Eohippus Skeleton

Evolution Controversy

There is a great deal of controversy about the evolution of horses, partly due to the initial misclassification of the eohippus. This is an ancestor of the equidae, however it may not have any relation to our domestic horse. Regardless of the shape of their family tree, it’s interesting to learn about all of the branches so I’ll keep sharing in the weeks to come. Before you go be sure to meet the also extinct Quagga.

2 Comments on “Eohippus or Hyracotherium – Extinct Equidae

Comments are closed.