In 1881, Nikolai Przewalski traveled to the steppes of Mongolia to put rumors of wild horses to rest. He found truly wild horses which had never been domesticated, which equines came to be known as Przewalski's horses, after the man who discovered them. This horse is not genetically identical to modern domesticated horses, but it is obviously related. Many modern horses such as the Norwegian Fjord horse share obvious characteristics with Przewalskis, suggesting that the horses may be the living ancestors of modern horses.
At one point in human history, wild horses wandered across most of Europe and Asia. They were captured for food initially, and then were used for riding and labor. It is likely that multiple species of wild horse were abundant at one time, but that human actions selected for the most docile and easy to domesticate species, resulting in the extinction of other wild horses. The Przewalski represents an important genetic link in human and equine history, and scientists have studied the horses in an attempt to learn more about the domestication of the horse.
When the Przewalski horse was first discovered, several foals were captured and used to establish small captive breeding stocks. Initially, these attempts were unsuccessful, and the horse proved difficult to keep in captivity until breeding and raising foals was perfected in the early twentieth century. Although this was primarily done to create an interesting exhibition for zoos and private collections, it may have saved the breed from extinction, as the breed vanished shortly after it was discovered; the last wild Przewalski horse was documented in the 1960s.
This might have been the end of the story for the Przewalski, except that a Dutch trio became concerned about the survival of the breed, and created a foundation to preserve and protect it in 1977. The foundation aimed to connect zoos with surviving populations of the horse and create a stable breeding program to save the breed. After concentrated effort, a small shipment of Przewalski horses were sent to Mongolia in 1992, and released in a nature preserve.
Przewalski horses show their relationship to modern horses in their appearance. Superficially, they resembles a very stocky, light colored mule. The horses have yellow dun coats with dark manes and tails, accented with a dark dorsal stripe running all the way down the back, and striped legs. The mane of this breed of horse is upright, and lacks a forelock. Also, despite the genetic differences between the Przewalski horse and the modern domesticated horse, the two are able to interbreed and raise offspring. For this reason, it is classified as a subspecies of the modern horse, rather than its own species.