Also, its premolar teeth became more like molars. These premolars are said to be "molariform." The primitive triangular premolar pulps food, while the squared molariform teeth crush and grind food. This might reflect a shift from a more diverse diet including fruit to a more limited diet of leaves and possibly grass. The first upper premolar is never molarized. It is only occasionally present in modern horses. It is popularly called the "wolf-tooth" by horse-breeders.
Hyracotherium Tooth Row		Mesohippus Tooth Row
	premolars molars		premolars molars Note how the premolars look very similar to the molars.
The premolars of Eocene horses, like Hyracotherium, Orohippus and Epihippus, were small and triangular compared to their molars.
At left, Mesohippus are browsing in their forest habitat in this 1913 painting by Bruce Horsfall.

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