Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
Equus scotti assigned fossils from the Anza-Borrego Desert in California, tentatively interpreted to represent "E. bautistensis", to "E. scotti". One of the reported locations farthest south in the Americas is Pali Aike National Park in Chile. Equus scotti Equus scotti (translated from Latin as Scott's horse, named after vertebrate paleontologist William Berryman Scott) is an extinct species of "Equus", the genus that includes the horse. "E. scotti" was native to North America and likely evolved from earlier, more zebra-like North American equids early in the Pleistocene Epoch. The species may have crossed from North America to Eurasia over the Bering land bridge