- CLASS: Mammalia (Mammals)
- ORDER: Perissodactyla
- FAMILY: Equidae
- GENUS: Equus
- SPECIES: ferus
- SUBSPECIES: przewalskii
Wild things: How do you say Przewalski's horse? It's quite a tongue twister for most Americans! It is pronounced either "sheh-VAHL-skee" or "per-zhuh-VAHL-skee" or even "PREZ-VAHL-skee," depending on the speaker. It is also known as the Asiatic wild horse or Mongolian wild horse. No matter what you call it, the Przewalski's horse is the closest living relative of the domestic horse. Like its cousins the zebras and the wild asses, all horses are in the family Equidae.
Przewalski’s horses weren't scientifically described until 1881, when army officer Nikolai Przewalski obtained a skull and hide of this rarely seen horse and shared them with scientists at a museum in St. Petersburg. Cave paintings 30,000 years old found in Spain and France depict a stocky wild horse with Przewalski's horse features.
Przewalski's horses are very definitely horses. They are stocky, short, and pot-bellied in comparison with other horses, with a spiky mane like a zebra and striped legs like the Somali wild ass. Coats may vary slightly in coloration, but all Przewalski's horses have a light belly and darker back, with a long, dark stripe on the back from the withers to the base of the tail. Typically, their legs and mane are darker than the body, like a bay horse. Unlike their horsey cousins, though, they don't have the lock of hair on the forehead, called a forelock. The pony-like head is rectangular and large in comparison with the rest of the body, and the ears are darkly rimmed.
HABITAT AND DIET
Przewalski's horses are always on the move through their large home ranges, which can be from 1 to 12 square miles (3 to 32 square kilometers). Bachelor stallions (adult males) cover the most ground, sometimes more than 13 miles (22 kilometers) a day, depending on the time of year. The horses amble between favored grazing spots and water sources during the day, resting when it gets too warm. In the winter, Mongolian gazelles and red deer may join the horse herd for added protection. Winter is long and hard for the horses, as food is much harder to find.
Przewalski's horses grow thick, warm coats for the winter, complete with long beards and neck hair. These coats are important during the harsh winters in their habitat in Mongolia, Kazakstan, and China, where temperatures can be freezing. In high winds, Przewalski's horses turn their back to the storm and tuck their tail tightly between their back legs! This may be an adaptation to help protect the eyes and nostrils, while also protecting the sensitive reproductive parts, from the severe winds and sand storms of the Gobi Desert.
Like their equine relatives, Przewalski's horses are grazers and mostly nibble on wild grasses. The horses graze together and rest together. Their sharp hooves are used to dig holes in the ground, if needed, to find water.
The Przewalski's horses at the San Diego Zoo Safari Park graze in their habitat but are also fed alfalfa, hay, and carrots.
It is thought that Przewalski's horses have never been successfully domesticated. They live in two kinds of large, distinct social groups: harem and bachelor groups. Harems rarely have more than 10 mares and their offspring up to 2 or 3 years of age and are led by one dominant stallion. Harem members all graze and rest at the same time. They spend a lot of time grooming one another, standing side by side, head to tail, and nibbling at one another's back and sides. This helps to reinforce social bonds within the group and also provides a good scratch!
When stallions are old enough to compete with the lead stallion, they are driven out of the harem and join small bachelor groups until they are mature enough to successfully compete for a harem group of their own.
When mares are old enough to reproduce, they may leave the harem group to join another. Foals are born after an 11-month gestation period, and they must be up and moving with the herd about 30 minutes after birth. By one week of age, foals are eating grasses and practicing their kicking skills. At one month of age, foals begin to play with other foals and older siblings in the herd. By two months old, they rarely need to nurse and begin to venture away from Mom, and by five months old, they are spending the same amount of time feeding as the adults and begin to drink water. Young horses stay with the group they were born into until they are sexually mature.
Wolves are the Przewalski's horse foal’s greatest natural enemy. To protect the little ones, the mares (adult females) form a defensive circle around the youngsters, and the stallion trots around the circle and charges. At night, one or more horses keep watch for predators while the others rest. Small herds are more vulnerable to attack, as there are fewer adults to protect the foals. Some mares leave the protection of the herd to give birth, and this often invites a wolf attack, as the mother does not have the help she needs to protect her foal (baby).
Like other horses, Przewalski’s horses call to each other with neighs and nickers. A snort can mean fear, frustration, or an alarm call, and a grunting “laugh” and sharp squeal are used by stallions during courtship. Stallions create “stud piles” of their feces to mark their territory and harem to other stallions in the area.
Przewalski's horses are native to a habitat called the steppe. Until 15,000 years ago, this immense and hardscrabble, sparse grassland habitat stretched from the east coast of Asia to present-day Spain and Portugal. After the last Ice Age, however, the steppe gave way to woods and forests, to which Przewalski's horses weren't well adapted. By the 19th century, the few horses that remained were confined to Mongolia, southern Russia, and Poland.
In the early 20th century, farmers and livestock took over good grazing lands, forcing the Przewalski's horses into areas that weren't suitable for human use. Wealthy aristocrats and westerners were fascinated by the unusual horses and collected foals to keep as pets. Przewalski's horses were spotted in Mongolia into the 1980s but became extinct in their native habitat about that same time.
Luckily, a small number of Przewalski's horses remained, scattered about in various zoos around the world. All Przewalski's horses alive today are descendants of 14 horses collected at the beginning of the 20th century.
In 1977, the Foundation for the Preservation and Protection of the Przewalski's Horse was founded, and an exchange of the horses between zoos throughout the world was started. In 1992, 16 horses were reintroduced into their native habitat in Mongolia, in an area that was later designated as Hustai National Park. As of 2011, the world's population of Przewalski's horses was about 1,400, with 250 of those being free-ranging. New zoo-bred horses continue to be introduced to the population, now located in four reserves in Mongolia and Kazahkstan, as well as the Kalameili Reserve in northern China.
Since 1979, San Diego Zoo Wildlife Alliance and a team of international conservation scientists have been leading the way in breeding, conservation genetics, and reintroduction of Przewalski’s horses. Our conservation scientists, in collaboration with researchers from the University of Pennsylvania, are studying the DNA of this endangered horse to determine genetic relationships in the remaining populations to guide conservation decisions. The DNA sequence of a fossil horse, estimated to be over 500,000 years old, has been compared with the Przewalski’s horse genome, reinforcing the separate genetic identity of the Przewalski’s horse as an ancient lineage tracing to today’s horses now gaining a foothold in nature once again. Information obtained through genome sequencing studies will help structure breeding programs, maintain genetic diversity, and focus reintroduction efforts for the "last wild horse."
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