''Equus occidentalis'' (commonly known as the western horse) was a

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...

, now extinct, that inhabited North America, specifically the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

. This species represents the larger end of the prehistoric horse spectrum – it was about the size of a

mustang The mustang is a free-roaming horse of the Western United States, descended from horses brought to the Americas by the Spanish. Mustangs are often referred to as wild horses, but because they are descended from once- domesticated animals, t ...

, weighing up to . It was a stoutly built animal and resembled the extinct

quagga The quagga ( or ) (''Equus quagga quagga'') is a subspecies of the plains zebra that was endemic to South Africa until it was hunted to extinction in the late 19th century. It was long thought to be a distinct species, but early genetic ...

or the modern

plains zebra The plains zebra (''Equus quagga'', formerly ''Equus burchellii''), also known as the common zebra, is the most common and geographically widespread species of zebra. Its range is fragmented, but spans much of southern and eastern Africa south o ...

, although it was not a close relative to either of these.

References

{{Taxonbar, from=Q5384754 Prehistoric mammals of North America Equus (genus) Taxa named by Richard Owen Fossil taxa described in 1863