The Przewalski horse, or takhi, is the only surviving species of “wild” horse (the American Mustang is genetically identical to the domestic horse, so it is not considered a true “wild” horse). Though the Przewalski horse has been known for centuries by the people who live on the grasslands of central Asia, it bears the name of the Russian naturalist Przewalski who “discovered” it in 1879.
Once widespread, by the early 1900s the Przewalski horse was facing heavy competition for water and grazing land. Because it was prized as a live specimen for zoos and private collections, hundreds of foals were captured and shipped to Europe or America, and most did not survive the difficult journey. The species was further damaged by hunting and by its proximity to domestic herds of Mongolian horses, which led to interbreeding. All these factors conspired against the survival of the Przewalski horse, and by 1969 it was extinct in the wild.
All living Przewalski horses are descended from a large group of foals that was captured during a single expedition in the early 20th century. Of the 53 foals that survived the journey from Mongolia to Europe, only 13 of them can be found in the ancestry of the modern Przewalski horse. This is because the species proved notoriously difficult to breed in captivity. Captive Przewalski horses were often kept in small enclosures, they were not able to graze, and there was very little exchange between zoos, which led to inbreeding and genetic problems such as high foal mortality and shortened lifespan.
There were only 300 surviving Przewalski horses worldwide when, in 1977, a small group of Dutch citizens formed The Foundation for the Preservation and Protection of the Przewalski Horse. The foundation established a computerized studbook and began encouraging and supporting the exchange of Przewalski horses between zoos in an effort to quell the ballooning problem of inbreeding. Its ultimate goal was the reintroduction of Przewalski horses into the wild.
Since Przewalski horses were now accustomed to living in zoos, reintroduction into the wild would be a difficult and taxing process. The horses needed to learn how to forage and how to live in herds. In 1981, the foundation began the process of reintroduction by purchasing Przewalski horses from zoos. They selected animals for their program based on pedigree information, giving preferential treatment to those horses who had very little common ancestry with other horses already in the program. By 1997, the foundation owned 61 Przewalski horses, all of which lived in one of five semi-reserves (natural or semi-natural areas of 12 acres or more). The foundation’s success in breeding these horses can be seen in its low foal mortality rate of 6%, and in the fact that 92% of its mares foal each spring.
The Przewalski horse reintroduction project officially began in 1990. A 24,000 acre Mongolian steppe area called Hustain Nuruu was set aside as a National Park and a reintroduction site for the species, and in June of 1992 16 Przewalski horses were shipped there for release into the wild. The foundation began regularly sending its second and third generation horses to the preserve in Mongolia, and by 1998 there were 60 plus Przewalski horses living on the Mongolian steppes, with 1,450 living in 135 zoos and private reserves worldwide.
About the Przewalski Horse The Przewalski horse is small but stocky, standing between 12 and 14 hands. Przewalski horses are always dun with a lighter color around the muzzle, an “eel-stripe” or black dorsal stripe, and zebra striping on the legs. It has an upright mane and no forelock, and a tail that is more reminiscent of a donkey than a domestic horse.
The Przewalski horse has 66 chromosomes, while the domestic horse has 64. The Przewalski horse can be crossed successfully with the domestic horse, producing offspring with 65 chromosomes. Unlike the offspring of a domestic horse and an animal such as a donkey or zebra, the offspring of a Przewalski/domestic horse is not sterile and can be crossed back to either species. If the offspring is crossed back to a domestic horse, the resulting animal will have 64 chromosomes and very few Przewalski characteristics.