Mustang

About the breed

The Mustang is a free-roaming feral horse of the western United States, not a breed with a studbook. US federal law defines wild horses as unbranded, unclaimed horses on public lands, and the Bureau of Land Management (BLM) states that most of today's wild horses descend from animals that were released by or escaped from Spanish explorers, ranchers, miners, the US Cavalry and Native Americans. Mustangs are therefore not uniform: herds differ in size, build and colour.

Not a breed: what the word means

The word mustang describes a way of life and a legal status rather than a pedigree. The Online Etymology Dictionary dates it in English to 1808 and traces it to Mexican Spanish mestengo, an animal that strays, from a Spanish word meaning wild, stray or ownerless. The Livestock Conservancy notes that the term "mustang" carries the connotation of any feral horse of any genetic background, so there is no single type: build, head, legs and colour differ from herd to herd. Federal law calls these animals "wild free-roaming horses and burros", the National Research Council calls them "free-ranging" and the Conservancy calls them feral; all describe horses living unclaimed on public land, most of them descended from domestic horses. Instead of papers, a horse adopted from the BLM carries a freeze mark, which can be used to look up certain details of its history in the programme's public data dashboard.

From Spanish horses to the Wild West

Horses returned to the Americas with the first European explorers. The Livestock Conservancy notes that Columbus brought horses from Spain to the West Indies on his second voyage in 1493 and that Cortés brought more to the mainland in the early 1500s. For centuries Spanish horses were the most common type west of the Mississippi, but from the mid-to-late 1800s almost all of them were crossed with, or replaced by, larger horses including Thoroughbreds and draught horses. Today's herds therefore carry a mixed heritage of ranch, cavalry, working and Spanish horses.

The 1971 Act and herd management areas

Wild horses have been protected by US law since 1971, when Congress passed the Wild Free-Roaming Horses and Burros Act. It calls wild horses and burros living symbols of the historic and pioneer spirit of the West and finds that they were fast disappearing from the American scene. The Act built on the 1959 "Wild Horse Annie Act", which banned hunting horses with motor vehicles and aircraft and outlawed poisoning watering holes on public lands. Today the BLM manages wild horses and burros on 175 herd management areas covering 25.6 million acres (about 10.4 million hectares) of public land, and wild horses are found in ten western states.

How many mustangs live in the US

The BLM estimated 61,523 wild horses, and 85,466 horses and burros in total, on the lands it manages as of 1 March 2026. The combined upper limit of the appropriate management level (AML) is 25,592 animals. Nevada held the most horses, 37,426. In May 2026 a further 53,773 horses were held in off-range corrals and pastures. According to the BLM, herds without natural controls such as predation can grow by up to 20 percent a year and double in four to five years.

The debate over herd management

How mustangs are managed is disputed in the US. The BLM removes ("gathers", that is, rounds up) horses above the appropriate management level (AML), the number it says can thrive in balance with other public land resources and uses, and offers them for adoption or sale; it also uses fertility control, which volunteers deliver by dart in herds where horses can be approached. A 2013 National Research Council committee described the disagreement itself: some parties are concerned that horse and burro numbers, which often exceed the AMLs, harm the range and other species, while other members of the public think that horses are unfairly restricted, that AMLs are too low to keep herds genetically healthy and that the animals are confined to too little public land; they are also concerned about the stress of gathers and holding facilities. The committee found that most herds grow by 15 to 20 percent a year, that the BLM's national population statistics could not be considered scientifically rigorous but probably underestimate the number of animals on the range, that removals may themselves allow population growth and so drive the need to remove more animals, and that AMLs are a focal point of controversy between the BLM and the public. The BLM says it adopted USGS survey methods in 2014. The committee named PZP vaccines, GonaCon and chemical vasectomy as the most promising fertility-control methods. The BLM states that it does not sell or send wild horses to slaughterhouses or kill buyers; since a 2004 amendment, however, it may sell horses over ten years old, or passed over for adoption three times, without limitation.

Height at the withers and weight: wide variation

Most mustangs stand 132 to 152 cm at the withers, which the BLM gives as 13 to 15 hands (hh; 1 hh = 10.16 cm; 52 to 60 inches), and weigh about 320 to 450 kg (700 to 1,000 lb). Because herds have different ancestry, height and weight vary a great deal. Horses on the King Top area in Utah average 13 to 14 hh (about 132 to 142 cm) and 700 to 900 lb (about 320 to 410 kg). In the South Steens area in Oregon they average 14 to 16 hh (about 142 to 163 cm) and 900 to 1,200 lb (about 410 to 545 kg).

Colours: from solid to spotted

A mustang can be almost any colour. The BLM describes wild horses as diverse in colouring, from solid brown and black to colourful pintos and palominos. Some herds are known for particular colours: Kiger horses in Oregon come in dun, grulla, buckskin and variations of these colours, including dorsal and zebra stripes. After gathers the BLM returns Kiger horses with dun colouring and Spanish mustang characteristics to the area to keep the core of the breeding herd.

Mustang vs Spanish Mustang: the difference

A BLM mustang is a legal category for a wild horse from public land, while the Spanish Mustang is a breed with breed registries such as the Spanish Mustang Registry. That registry states plainly on its website that the Spanish Mustang is not to be confused with the BLM mustang. The registry grew out of a group formed in the mid-1950s around Robert E. Brislawn of Wyoming, who collected horses of the old Spanish type, and it says fewer than 3,000 Spanish Mustangs remain today. The Livestock Conservancy groups these horses as Colonial Spanish horses standing 13.2 to 15 hh (54 to 60 inches, about 137 to 152 cm; 13.2 hh means 13 hands 2 inches) and adds that only a very small minority of North American feral horses qualify as Spanish in type and breeding. The 2013 review summarises blood-group studies that found evidence of Spanish blood in the Cerbat Mountains (Arizona), Pryor Mountains (Montana) and Sulphur (Utah) herds.

Temperament: wary at first, then willing to learn

A mustang straight from the range is wary of people, because, as the BLM notes, wild horses tend to avoid human contact. The BLM describes them as sure-footed, strong, intelligent horses with endurance that can be trained for many uses with kindness and patience. The BLM care guide advises starting the gentling process as soon as possible but taking time, staying safe and going slowly; the BLM adoption FAQ adds that an ungentled horse (one not yet handled or trained to accept people) should not be released into a large open area such as a pasture, where it may not be recaptured for training or veterinary care. How quickly a horse learns to trust people depends on the individual, its age and the trainer's experience.

Adopting from the BLM: the requirements

Since 1971 the BLM has placed more than 290,000 wild horses and burros through adoption. Adopters must be at least 18 years old and have no convictions of inhumane treatment of animals or of violating the Wild Free-Roaming Horses and Burros Act. An untrained horse needs at least 400 square feet (about 37 m²) of corral space, and the fence must be 6 feet (about 1.83 m) high for an ungentled horse aged two or over, or 5 feet (about 1.52 m) for a yearling or gentled horse. Shelter and a covered stock trailer are also required. The base fee is 125 dollars, though at some adoption events competitive bidding can raise it (BLM adoption FAQ, checked September 2026). The horse remains federal property for at least one year and must stay in the United States until titled; the BLM issues the title once a veterinarian or other qualified person confirms humane care. Before adoption every horse is vaccinated, dewormed, freeze-marked and tested negative on a Coggins test for equine infectious anaemia.

Uses: from trail riding to dressage

A trained mustang is a versatile riding horse. The BLM says wild horses have become champions in dressage, jumping, barrel racing, endurance riding and pleasure riding. It works with non-profit groups, volunteers and state and county prisons that train horses before placement, because trained animals are adopted more readily. The German organisation American Mustang Germany, which runs the Mustang Makeover event (since 2017), says it has placed over 500 mustangs in Europe. According to the event's FAQ, the trainers work with their mustangs for about 120 to 160 days, and the mustangs are imported to Germany by air.

The first weeks at home: settling in and routine care

The first weeks after arrival are the most delicate. The BLM care guide advises keeping activity around the corral to a minimum for the first few days and watching the horse closely for signs of illness for three to four weeks, because stress combined with exposure to large groups of horses means a higher chance of illness. The guide says a new horse may settle more easily if it can see other horses nearby, but that it is probably best not to mix them right away. The horse should learn to pick up its feet early, since hooves grow quickly in captivity and no longer wear as they did on the range; under the UK DEFRA Code of Practice for the Welfare of Horses the farrier should trim or shoe as advised, usually every 4 to 8 weeks. Teeth should be checked by a vet or equine dental technician at least once a year. Vaccination and infectious-disease control, and a parasite control programme with faecal worm egg counts, should be agreed with a vet.

Housing, feeding and exercise

A mustang is a herd animal and needs the company of other horses. The UK DEFRA code of practice points out that horses in the wild live in relatively stable groups and that isolating a horse from other horses can have a negative psychological impact. Horses evolved to spend 16 to 20 hours a day grazing and browsing, so a mustang needs almost constant access to forage such as grass, hay or haylage, and continuous access to fresh water. Concentrates should be limited to what work or weight gain requires, and any change of diet should be gradual. The BLM care guide also advises exercising the horse regularly for good overall health and condition. Once the horse is used to the fences and can be reliably caught, the guide says it will do much better turned out in a small pasture or dry lot than kept in a small pen or stall.

Health and lifespan

The sources used here give no disease or lifespan figures specific to mustangs. The 2013 National Research Council review found that phenotypic data had not been recorded and integrated into the genetic management of free-ranging herds; recording the occurrence of diseases and clinical signs, it said, would let the BLM monitor genetic conditions. The review also found that genetic diversity in most of the 102 herd management areas studied was similar to that of healthy mammal populations, although that could change in time, with the lowest values in some small, isolated herds; it recommended that the BLM manage connected herds as a metapopulation. This is a question of herd management, not a prediction for an individual horse. As a general guide, the Merck Veterinary Manual states that horses live 25 to 30 years on average, depending on health, care and size.

Who the Mustang suits

The Mustang suits an experienced horse person or rider with time, a secure corral and a trainer's support who wants a hardy horse for trail, leisure or sport. An ungentled BLM horse is generally not suited to a beginner without an experienced trainer, whereas an already trained mustang with a proven temperament can suit a less experienced rider working under a trainer. Children cannot adopt from the BLM (adopters must be at least 18), and whether a child can ride or handle a mustang depends on the individual horse, its schooling and a trainer's supervision; an ungentled horse is generally not suited to children. A mustang needs other horses for company, forage, daily exercise and regular visits from the farrier, vet and equine dentist. With an adopted horse it helps to keep a running record of vaccinations, worming and farrier visits, since the BLM hands over a health record at adoption that serves as the starting point for further care.

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