North America's only wild horses became extinct more than 10,000 years ago. The mustangs we know today are descendants of domestic horses (Equus callabus) brought to the U.S. by the Spanish in the 16th century. Since mustangs roam freely and survive on their own, they are referred to as wild, but are actually feral horses. There are two genuine wild horses. One is Przewalski's Horse (Equus callabus przewalski), native to Asia; and the Tarpan (Equus ferus ferus), which originates from middle to Eastern Europe.
Humans began domesticating horses approximately 5,000 years ago. Horses have made a significant impact on the world's history, unlike any other animal. The horse's domestication has resulted in an incredible animal capable of changing the face of warfare, enabling the expansion of territories and facilitating cultural and economic progress. Today, domestic horses work alongside police officers, help farmers plough their fields, work as guides for the blind and serve as loyal companions to their owners. Domestic horses are bred to maintain or produce specific bloodlines, depending upon the riding discipline, such as horseracing, English or western pleasure, rodeo, dressage or jumping.
Although North America's horse population became extinct, some herds migrated over land bridges into Spain and Portugal. When Spanish explorers came to the America's in search of fortune, they brought their strong, sturdy horses with them. They raised their horses on sheep and cattle ranches in New Mexico, but some escaped. Those free-roaming horses became known as "mustangs." The Spanish word for mustang is mesteno, meaning "free-running animal." As more settlers travelled across the western prairies, other breeds of ponies and horses were introduced to the feral herds, including Morgans, Belgians, Percherons and Clydesdales. The crossbreeding of the conquistador's horses with these breeds produced the exceptionally strong, hardy horses that we know today as mustangs. Today, wild mustangs live in wildlife refuges, Native American reservations and on federal land throughout Colorado, Utah, Nevada, Wyoming, Oregon and Montana.
Przewalski's horses became extinct in the wild. However, they were reintroduced through approximately 13 remaining individuals secured in zoos. Efforts to preserve them continue, and all are registered in a worldwide stud book in Cologne, Germany. The relationship between Przewalski's horses and domestic horses has long been a source of debate between scientists. Research has uncovered that the Asian wild horse has 66 chromosomes and domestic horses have 64. DNA analysis illustrates that no evidence of Przewalski's horse blood in domestic horse breeds exists. Physically, they differ from domestic horses in that their manes are short and rigid, their forelocks are nearly nonexistent, they have a dark dorsal stripe that runs down their backs, and they shed their manes and tails once a year.
Tarpan horses are prehistoric wild horses that lived from Southern France and Spain to central Russia. The species became extinct when the last Tarpan was killed at an Ukranian game preserve in 1876. Like the North American mustang, the Tarpan was seen as a nuisance to farmers. A genetic recreation of the Tarpan was produced by two German zoologists. Because several European pony breeds were descendents of Tarpans, they used a combination of Icelandic Ponies and Swedish Gotlands, and bred the mares to Przewalski stallions. The first Tarpan colt was born on May 22, 1993 in Munich, Germany. Work continues to bring this prehistorical equine species back from extinction.