Pryor Mountain Mustang

  • HEIGHT: 13–15 hands, with an average of 14–14.2.
  • PLACE OF ORIGIN: Pryor Mountains, on the border between Montana and Wyoming
  • SPECIAL QUALITIES: A gaited breed of Spanish Colonial type, showing a wide array of solid colors; many exhibit primitive markings such as dorsal stripes, shoulder crosses, and zebra stripes on the legs
  • BEST SUITED FOR: Trail, pleasure, endurance riding; ranch work; good choice for riders with physical limitations or a bad back and bad knees

The Lewis and Clark expedition passed through south-central Montana in 1806. One of the members of that mapping and exploration party was Sergeant Nathanial Pryor, whose name was later given to the nearby Pryor Mountains. How horses first made their way to the rugged and isolated Pryor Mountains is unclear. Some believe they were first brought there by Crow horse traders, others that they descend from horses that escaped or were stolen from the Lewis and Clark expedition. What is clear from historical records is that they have been in the area for at least two hundred years.

In 1968, three years before the Wild Free-Roaming Horse and Burro Act extended federal protection to wild horses, the 31,000-acre National Wild Horse Refuge was established in the Pryor Mountains. Just south of Billings, Montana, and north of the Wyoming border, the refuge is adjacent to the Big Horn Canyon National Recreation area. The land ranges from arid lowlands to alpine meadows at 8,700 feet of elevation, and wild horses roam throughout depending on the season and the temperature. The horses tolerate winter temperatures that dip to 20 to 30 degrees below zero.

Two members of the Pryor Mountain herd engage in mutual grooming.

A number of foals are born to the herd every year. Without the influence of any outside breeds, the Pryor Mountain Mustangs are true exemplars of Spanish characteristics in conformation, gait, and color.

Observation always suggested that the Pryor Horses were a distinct type. When Gus Cothran, of the University of Kentucky, performed genetic testing, he confirmed both that this is a distinct population and that the horses have what are known as old genetic markers or old Spanish markers linking them quite directly with the early horses brought to North America by the Spanish. Furthermore, there has been very little dilution of the Spanish markers, indicating that almost nothing else was ever crossed in among them.

Although many of the rugged Pryors exhibit dun coloring and dun-factor markings, they come in a range of colors.

The Pryor Mountain Horses are among the purest of any populations of horses of Spanish descent in North America. Typical of such horses, the Pryor Horses are smooth-gaited. Many of them, including those caught from wild herds as well as those born in captivity, will naturally demonstrate an amble, and they seem particularly to fall in to the smooth ambling gait when put under saddle. This makes them very comfortable to ride. They also fox trot.

The refuge is home to between 120 and 160 wild horses, which share it with elk, bighorn sheep, and other wildlife. In the past the horses were protected from predators, but observers have noted that mountain lions are now present and have taken a few foals.

The horses separate themselves into small herds of five or six mature animals, consisting of a stallion, a dominant mare, and several other mares and their foals. Bachelor stallions, often immature animals, follow along, joining and leaving groups from time to time.

Pure Spanish Blood

The word mustang comes from the Spanish word for “stray,” which in turn derives from the Latin word mixta, meaning “mixed.” Mustangs are mixed-breed strays. In the case of the Pryor Mountain Mustangs, the Kiger Mustangs, and other true Spanish Mustangs, they may have been of mixed Spanish descent two hundred or more years ago, but since that time no other horse breeds have been added to their population.

Furthermore, ever since the Pryor herd was established, all selection has been environmental, with no human intervention. The weak and unsound horses were killed or have died off in accidents. The survivors are compact, tough horses well adapted to their world.

Breed Characteristics

Well put together and attractive, Pryor horses have a reputation for excellent endurance as well as for the ability to carry weight. People familiar with them say that they carry themselves with brio (fire) and pride, and that their temperament is noble and kind. Pryor Horses are easily gentled and form a strong bond with their handlers. Experienced owners note that the horses have a natural wariness, which comes from their life in the wild, but that they are very quick learners and exceptionally easy to work with once trust has been established. They readily accept training as long as they are taught rather than forced, but will resist unreasonable handling.

Pryor Horses have high knee action and sometimes exhibit termino, swinging front leg placement. They are sure-footed, well balanced, and athletic.


Pryor Mountain Mustangs usually stand between 13 and 15 hands, with an average size of 14 to 14.2 in wild-caught horses. Horses born on ranches from wild-caught parents tend to be at the larger end of the size range because of better nutrition.

The conformation is typical of Spanish Colonial Horses. They have a medium to long head with a flat or slightly convex profile. As seen from the front, the forehead is wide with large, very expressive, almond-shaped eyes, and the face tapers to a fine muzzle. The medium-length neck is slightly thick and the body somewhat narrow but deep. The shoulders are generally long and sloping with distinct withers.

The back is fairly short. Some Pryor Mountain horses have only five lumbar vertebrae, or the fifth and sixth vertebrae are fused. Many of the horses have the typically Spanish sloping croup with a low tail set. The horses have substantial, dense bone. The chestnuts are very small or absent. The feet are of good size and extremely hard.

The mane and tail are long, full, and silky, and the winter coat is extremely thick and curly.


Pryor Horses exhibit a wide variety of solid colors, and many of the horses have “primitive” markings, such as dorsal stripes, shoulder crosses, and zebra stripes on the legs, sometimes extending as high as the gaskins. There are various shades of grulla and duns in many shades, from apricot and claybank to golden, as well as red and blue roans, palominos, and true blacks.

White markings on the face and lower legs are minimal if they occur at all. Pintos and grays are virtually unknown.


The Pryor Mountain Breeders Association was started in 1992 to establish and preserve a gene pool. The breeders association also strives to demonstrate the versatility, endurance, and intelligence of Pryor Mountain Mustangs.

• As of 2004, there were 164 horses registered with the association.

• The horses are found in 11 states: Montana, Wyoming, North Dakota, Idaho, Oregon, Missouri, Illinois, Massachusetts, South Dakota, Utah, and Florida.

1 Comment

  • The Pryor adopted horses also live in Colorado and Virginia in addition to the states you mentioned. Cloud’s sister,
    Mahogany was removed in 1997 and was a nationally ranked limited distance endurance horse. Mahogany exhibits the single-footed gait which takes the bounce out of the trot, a feature enjoyed by her adopter and rider, Ann Evans.
    Thanks so much for this interesting and accurate summary of the herd. I enjoyed reading! The roan mare with her
    little foal with the star and snip are Cloud’s daughter Shadow and her son, Uno Caballo born in July 2020..
    Ginger Kathrens
    The Cloud Foundation

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