So how did horses evolve? What was once thought a "done-deal" question in the field of biology (and a benchmark proof of evolution itself) has now received a bit of a shakeup, according to this BBCnews article:

As the Great Ice Age came to an end, some 11,000 years ago, North America was thought to be home to as many as 50 species and subspecies of horse.

But studies of ancient DNA tell a rather different story, suggesting the horses belonged to just two species.

Even the movement and timing of the species is now being revised. DNA rocks!