What is a mustang?

A mustang is a free-roaming horse found primarily in the western United States, descended from domesticated horses brought to North America by Spanish explorers in the 16th century and subsequently escaped or released over centuries of settlement and ranching. The term mustang comes from the Spanish word mestengo, meaning stray or ownerless, and the horses it describes are not truly wild in the biological sense — they are feral, meaning they are descended from domesticated stock rather than being a species that has never been domesticated. Over generations of living without human management, mustangs have developed the hardiness, sure-footedness, and survival instincts that make them distinctive as horses — their hooves are notably durable from traveling rough terrain, their metabolisms are efficient from adapting to sparse grazing, and their flight instinct and social behaviors reflect centuries of living without human protection. Mustangs are managed by the Bureau of Land Management as part of the federal wild horse and burro program established by the Wild Free-Roaming Horses and Burros Act of 1971, which gave these animals protected status on federal public lands. Today mustang herds roam across ten western states, with the largest populations in Nevada, Wyoming, and Montana. Their size, color, and conformation vary considerably by region and bloodline, reflecting the diverse domestic stock from which different herds descended, with some herds showing clear Spanish ancestry and others reflecting later introductions of draft, quarter horse, or thoroughbred blood.