![Evolution of the horse over the past 55 million years. The present-day Przewalski’s horse is …[Credits : Encyclopædia Britannica, Inc.]](http://media-2.web.britannica.com/eb-media/03/55003-004-DEA45BCE.jpg)
Evolution of the horse over the past 55 million years. The present-day Przewalski’s horse is believed to be the only remaining example of a wild horse—i.e., the last remaining modern horse to have evolved by natural selection. Numbered bones in the forefoot illustrations trace the gradual transition from a four-toed to a one-toed animal. Click on an individual animal’s image for a larger view. Click on the animal’s name to see an article on the topic.
We welcome your comments. Any revisions or updates suggested for this article will be reviewed by our editorial staff. Contact us here.
Regular users of Britannica may notice that this comments feature is less robust than in the past. This is only temporary, while we make the transition to a dramatically new and richer site. The functionality of the system will be restored soon.