The Appaloosa is a horse breed known for its preferred leopard-spotted coat pattern and other distinctive physical characteristics. While there is evidence of leopard-spotted horses dating back to the Paleolithic era in Europe, the Nez Perce people of the American Pacific Northwest developed the American breed. They were once referred to by white settlers as the "Palouse horse", possibly after the Palouse River, which ran through the heart of Nez Perce country. Gradually, the name evolved into "Appaloosa". The Nez Perce people lost most of their horses following the end of the Nez Perce War in 1877 and the breed fell into decline for several decades. However, a small number of dedicated breeders kept the Appaloosa alive for several decades until a registry was formed in 1938. Today the Appaloosa is one of the most popular breeds in the United States, and it was named the official state horse of Idaho in 1975.
The Appaloosa is best known as a stock horse used in a number of western riding disciplines, but is also a versatile breed with representatives seen in many other types of equestrian activity, as well as in many movies. The color pattern of the Appaloosa is of great interest to those who study equine coat color genetics, as both the coat pattern and several other physical characteristics are linked to the "Lp" or "leopard" gene or gene complex, but the precise inheritance mechanism is not fully understood. The Appaloosa has influenced many other horse breeds, including several gaited horse breeds.
The Appaloosa is known for its preferred leopard-spotted coat pattern and other distinctive physical characteristics. Because the spotting pattern is a preferred identifying factor, and because several different horse breeds influenced the Appaloosa, there are several body styles found in the breed. Due to this wide variety, Appaloosas are used in many different disciplines.
Most Appaloosas are recognized by their colorful spotted coat, striped hooves, mottled skin (most visible around their eyes and on their muzzle) and white sclera around the eye. Appaloosas can have brown, blue or hazel eyes, and an individual horse may have eyes of two different colors. While the original, "old time" Appaloosas often had a sparse mane and tail, it was not a predisposition for the breed as a whole; even many original Appaloosas had full manes and tails. Today the "rat tail" trait is usually bred away from and most "modern" Appaloosas have full manes and tails.
The physical conformation of the original Appaloosa was typical of the range horses found in the western United States. Original or "old style" Appaloosas were highly regarded as hardy working horses. Many ranchers and horse breeders used roan or minimally marked Appaloosas in their programs, particularly in parts of Texas and Colorado. This had an impact on the development of the American Quarter Horse, especially with regard to the Peavy, Roberd and Casement herds. Modern Appaloosas are both more refined and more muscular, reflecting the influence of Arabian and Thoroughbred breeding as well as infusions from modern American Quarter Horses and other lines.
Appaloosas with a "stock horse" build are well suited to western riding disciplines as well as to short-length horse racing, at distances from 220 yards (200 m) up to a quarter-mile (400 m). The "foundation" or "working" Appaloosa is still sometimes seen, especially on working ranches. This is a slightly smaller, leaner animal considered to be closer in type to the original Nez Perce bloodstock. There are also some Appaloosas that display more of a Thoroughbred or sport horse conformation - taller, with longer legs and a leaner build, bred to be used in English riding competition and middle distance horse races up to 8 furlongs (1.0 mi). A similarly spotted breed in Europe, with a sport horse build, is the Knabstrup.
The base color of the Appaloosa horse can include bay, black, chestnut, palomino, buckskin, dun and grullo. However, it is the unique spotting pattern that most people associate with the Appaloosa horse. These spotted markings are not the same as the "dapples" sometimes seen in grays and some other horse colors. Appaloosa markings overlay the base coat color, and have several pattern variations.
It is not always easy to predict the color a grown horse will be from the shade it has as a foal. Most foals are born with lighter colored coats than they will have when they shed their baby hair with the exception of gray horses, which are born dark and progressively become lighter.