Przewalski's Horse

Dzungarian horse, is a rare and endangered subspecies of wild horse (Equus ferus) native to the steppes of central Asia. At one time extinct in the wild (in Mongolia, the last wild Przewalski's horses had been seen in 1966), it has been reintroduced to its native habitat in Mongolia at the Khustain Nuruu National Park, Takhin Tal Nature Reserve, and Khomiin Tal.[1] The taxonomic position is still debated, and some taxonomists treat Przewalski's horse as a species, Equus przewalskii. Common names for this equine include Asian wild horse, Przewalski's wild horse, Mongolian wild horse, and takhi. Historical but obsolete names include true tarpan and Mongolian tarpan. The horse is named after the Russian geographer and explorer Nikolai Przhevalsky. Most "wild" horses today, such as the American Mustang or the Australian Brumby, are actually feral horses descended from domesticated animals that escaped and adapted to life in the wild. In contrast, Przewalski's horse has never been domesticated and remains the only truly wild horse in the world today. Przewalski's horse is one of three known subspecies of Equus ferus, the others being the domesticated horse Equus ferus caballus, and the extinct tarpan Equus ferus ferus. There are still a number of other wild equines, including three species of zebra and various subspecies of the African wild ass, onager (including the Mongolian wild ass), and kiang. Phylogeny Many believe that the Przewalski horse is the closest relative to the domestic horse, although there have been many debates on whether the Przewalski horse has a direct linkage to the domesticated horse. Studies of the DNA diversity within the Przewalski horses have been done to see how successful their reintroduction into the wild may be. Studies have shown through multidimensional scaling analyses that tight grouping occurs within most horse breeds, close grouping between related breeds, and far less grouping between mixed breeds. The Przewalski horse and the domesticated horse showed a close relationship through pairwise genetic distance and multidimensional scaling analyses showing that the Przewalski horse is very closely related to the domesticated horse. Taxonomy The Przewalski's horse was described in 1881 by L. S. Poliakov. The taxonomic position of Przewalski's horse has always been problematic and no consensus exists whether it is a full species (Equus przewalskii), a subspecies of the wild horse (Equus ferus przewalskii), or even a sub-population of the horse (Equus ferus). Studies using DNA have been inconclusive, in part due to crossing domestic horses into the Przewalski's horse as well as the limited genetic variation present in the founder population of the Przewalski's horse. A 2009 molecular study using ancient DNA recovered from archaeological finds like bones and teeth places the Przewalski's horse in the middle of the domesticated horses, but 2011 mitochondrial DNA analysis suggests that the Przewalski and the modern domestic horse diverged some 160,000 years ago.[9] An analysis based on whole genome sequencing and calibration with DNA from old horse bones gave a divergence date of 38–72 thousand years ago. Characteristics Przewalski's horse is stockily built in comparison to domesticated horses, with shorter legs. Typical height is about 12–14 hands (48–56 inches, 122–142 cm), length is about 2.1 m (6 ft 11 in). They weigh around 300 kilograms (660 lb). The coat is generally dun in color with pangaré features, varying from dark brown around the mane (which stands erect) to pale brown on the flanks and yellowish-white on the belly and around the muzzle. The legs of Przewalski's horse are often faintly striped, also typical of primitive markings. The tail is about 90 cm (35.43 in) long, with a longer dock and shorter hair than seen in domesticated horses. The hooves of the Przewalski's horse are longer in the back and have significantly thicker sole horn.