The Hagerman horse ( Equus simplicidens ), also called the Hagerman zebra or the American zebra, was a North American species of equid from the Pliocene epoch and the Pleistocene epoch. The Hagerman horse (Equus simplicidens) is the oldest known representative of the modern horse genus Equus (which includes horses, donkeys, and zebras) and is believed to be more closely related to the living Grevy's zebra in Africa than our modern horse. Included are complete skeletons as well as skulls, jaws and detached bones. Hagerman "Horse" - Equus simplicidens. What makes the Hagerman Horse so important? It is the state fossil of Idaho. The Hagerman Horse sips water as preditors draw near. Idaho also recognizes an official state horse. (Adapted from the Hagerman Fossil Beds Official Map and Guide.)

The Hagerman Horse, Equus simplicidens, exemplifies the quality of the fossils. The Hagerman Horse Quarry fossil beds have produced 20 complete skeletons and a number of partial skeletons of this zebra-like ancestor of today’s horse. Over two hundred individuals of both sexes and all ages were recovered by the Smithsonian. These horses include adults and foals and occur in two distinct concentrations (bone beds). Also known as the Hagerman Horse, the American Zebra (Equus simplicidens) was closely related to the still-extant Grevy's Zebra (Equus grevyi) of eastern Africa, and … First, the discovery from Hagerman is the largest sample of this extinct species from one locality. Over 200 individuals have been pulled from the Hagerman Horse Quarry. It was one of the oldest horses of the genus Equus and was discovered in 1928 in Hagerman, Idaho.

The star of Hagerman is its horse, Equus simplicidens.