The specimens were found in what is now an arid desert. But at the time this grass-eating horse roamed the planet, the region would have been covered in grasslands and shrubby woods -- rich grounds for grazing.

Fossilized traces of the horse, which was named Eurygnathohippus woldegabrieli, were uncovered in the archaeologically rich sites of Aramis and Gona in Ethiopia's Middle Awash valley. The region is famed for bearing the world's longest and most continuous record of human evolution.

The extinct horse in this study would have actually been alive at the same time the 4.4-million-year-old human ancestor Ardipithecus ramidus, or "Ardi," walked the region.