Mustang

Because they are descended from once-domesticated horses, they can be classified as feral horses.

In 1971, the United States Congress recognized that "wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of the West, which continue to contribute to the diversity of life forms within the Nation and enrich the lives of the American people." In the 21st century, mustang herds vary in the degree to which they can be traced to original Iberian horses. Some contain a greater genetic mixture of ranch stock and more recent breed releases, while others are relatively unchanged from the original Iberian stock, most strongly represented in the most isolated populations.

The free-roaming mustang population is managed and protected by the Bureau of Land Management (BLM). Controversy surrounds the sharing of land and resources by the free-ranging mustangs with the livestock of the ranching industry, and also with the methods with which the federal government manages the wild population numbers. A policy of rounding up excess population and offering these horses for adoption to private owners has been inadequate to address questions of population control, and many animals now live in temporary holding areas, kept in captivity but not adopted to permanent homes.

Etymology and usage

Mustangs are often referred to as wild horses but, since all free-roaming horses now in the Americas descended from horses that were once domesticated, the more correct term is feral horses.

The English word mustang comes from the Mexican Spanish word mestengo, derived from Spanish mesteño, meaning "stray livestock animal". The Spanish word in turn may possibly originate from the Latin expression animalia mixta (mixed beasts), referring to beasts of uncertain ownership, which were distributed in shepherd councils, known as mestas in medieval Spain. A mestengo was any animal distributed in those councils, and by extension any feral animal.

The horse family Equidae and the genus Equus evolved in North America and existed in prehistoric times. Studies using ancient DNA as well as DNA of recent individuals shows there once were two closely related horse species in North America, the wild horse (Equus ferus), and the stilt-legged horse (taxonomically assigned to various names). However, the genus Equus in North America died out at the end of the last ice age around 10-12 thousand years ago, possibly due to a changing climate or the impact of newly arrived human hunters. Thus at the beginning of the Columbian Exchange, there were no equids in the Americas at all. Horses first returned with the conquistadors, beginning with Columbus, who imported horses from Spain to the West Indies on his second voyage in 1493. Domesticated horses came to the mainland with the arrival of Cortés in 1519. The only extant true wild horse is the Przewalski's horse, native to Mongolia.

The first mustangs descended from Iberian horses brought to Mexico and Florida. Some of these horses were sold, escaped or were captured by Native Americans, and rapidly spread by trade and other means throughout western North America.

Native Americans quickly adopted the horse as a primary means of transportation. Horses replaced the dog as a travois puller and greatly improved success in battles, trade, and hunts, particularly bison hunts.

Mustang runners" were usually cowboys in the U.S. and vaqueros or mesteñeros in Mexico who caught, broke and drove free-ranging horses to market in the Spanish and later Mexican, and still later American territories of what is now Northern Mexico, Texas, New Mexico and California. They caught the horses that roamed the Great Plains and the San Joaquin Valley of California, and later in the Great Basin, from the 18th century to the early 20th century.