The Mustang is a free-roaming feral horse of the North American west that descends from horses brought to the Americas by Spanish conquistadors beginning in the sixteenth century. The name derives from the Spanish word mesteno, meaning stray or ownerless livestock. Escaped and released horses from Spanish colonial settlements established free-ranging herds, which later incorporated individuals from other breeds introduced by Native American nations and settlers, producing the genetically diverse population recognized today. Mustangs inhabit public lands managed by the Bureau of Land Management, primarily across Nevada, Wyoming, Colorado, Montana, Idaho, Utah, Oregon, and California. They are compact, hardy horses typically standing 14 to 15 hands and weighing 700 to 900 pounds, with a wide range of coat colors reflecting their mixed ancestry. The Pryor Mountain and Kiger strains retain strong colonial Spanish characteristics. Mustangs can be gelded and trained and have been adopted as riding horses across western and trail disciplines; the BLM’s Mustang Heritage Foundation administers the Trainer Incentive Program and adoption events to place excess animals. Their legal status as a protected species is defined by the Wild Free-Roaming Horses and Burros Act of 1971. See also coat color genetics to understand the broad variation that reflects the Mustang’s mixed ancestry, and registered breed standards for the formal contrast with this unregistered feral population.
Further Reading: The Bureau of Land Management administers wild horse and burro herds on public lands; the program overview and adoption information are at BLM Wild Horse and Burro Program. The full population history and breed characteristics are documented on Wikipedia’s Mustang (horse) page.