Are There Still Wild Horses? Mustangs and Przewalski's Horse

Wild vs feral: what is the difference?

Biologists use the word wild for animals whose ancestors were never domesticated. A feral animal lives free but comes from domestic stock, like a cat living in the woods. Feral horses can be just as independent and wary as wild ones, and they behave much like their ancient ancestors, but their genes come from the domestic horse.

Until recently there were two kinds of wild horse:

• The tarpan (Equus ferus ferus), a gray-brown wild horse of Europe and western Asia. Hunting and farming pushed it out, and the last known tarpan died in captivity in Russia in 1909. Breeds such as the Konik and the Heck horse were later bred to look like tarpans, but they descend from domestic horses.
• Przewalski’s horse (Equus ferus przewalskii), also known as the takhi or Mongolian wild horse, which survives today.

Przewalski’s horse: back from extinction in the wild

Przewalski’s horse is a stocky, dun-colored horse about 1.2–1.4 m (48–56 in) tall at the withers, with a short, upright dark mane, a pale muzzle and often faint stripes on the legs. It has 66 chromosomes, two more than domestic horses, though the two can interbreed. It is named after the Russian explorer Nikolai Przhevalsky, who obtained a skull and hide for scientists in the late 1870s.

The species once roamed the steppes and semi-deserts of Central Asia. Hunting, competition with livestock for water and grazing, and harsh winters drove it to extinction in the wild. The last confirmed sighting of a wild Przewalski’s horse was a single stallion in Mongolia in 1969.

Saved by zoos

Fortunately, horses captured around 1900 had been bred in zoos. All living Przewalski’s horses descend from little more than a dozen founders, including at least one domestic mare, so careful studbook management was needed to limit inbreeding. By the early 1990s there were more than 1,500 in captivity.

In 1992, the first zoo-bred horses were released in Mongolia, at Hustai (Khustain Nuruu) National Park and at Takhin Tal in the Gobi. More reintroductions followed in Mongolia, China and Kazakhstan, and a herd released in Ukraine’s Chernobyl Exclusion Zone in 1998 has bred there. The IUCN Red List moved the species from Extinct in the Wild to Critically Endangered in 2008 and to Endangered in 2011. Today there are roughly 2,000 or more in total, with several hundred living free in Mongolia.

The Botai twist

In 2018, a team led by Charleen Gaunitz and Ludovic Orlando published ancient DNA from horses of the Botai culture of Kazakhstan, where people kept horses about 5,500 years ago. The study, in Science, found that Przewalski’s horses descend from these early herded horses. If so, Przewalski’s horses are not strictly wild but the feral descendants of one of the first attempts at horse keeping.

Not everyone agrees on how to interpret the results, and whether the Botai horses were fully domesticated is still debated. Either way, Przewalski’s horse has lived without human control for thousands of years and remains the closest thing to a truly wild horse alive today.

Mustangs: the feral horses of the American West

Horses died out in the Americas about 10,000 years ago and returned with the Spanish from 1493. Escaped and released Spanish horses, later mixed with ranch, farm and cavalry horses, gave rise to the mustang, from the Spanish mesteño, meaning a stray animal.

Mustangs are protected on federal land by the Wild Free-Roaming Horses and Burros Act of 1971 and managed by the Bureau of Land Management (BLM). Nevada holds the largest share of them, with other herds in Wyoming, Utah, Oregon, California and neighboring states. BLM estimates in recent years have ranged from roughly 70,000 to 88,000 wild horses and burros on its western rangelands, well above its target of about 27,000. How to manage these herds, through roundups, adoption and fertility control, remains a hot topic.

Other feral horses around the world

• Brumbies (Australia): Australia’s feral horses number in the hundreds of thousands, with at least 400,000 identified in a 2011 survey. Herds in the Australian Alps are a heritage symbol to some and a threat to fragile mountain wetlands to others.
• Sable Island horses (Canada): several hundred horses live unmanaged on a narrow, treeless island off Nova Scotia, now a national park reserve.
• Assateague and Chincoteague ponies (US): feral horses on Assateague Island off Maryland and Virginia, famous for the annual Chincoteague pony swim.
• Namib Desert horses (Namibia): a small herd that survives in the desert near the town of Aus.
• Kaimanawa horses (New Zealand): a feral population on the central North Island.

Semi-wild horses and ponies in Europe

Europe has many free-living herds that are owned or managed by people but live largely wild. In England, Exmoor, Dartmoor and New Forest ponies graze open moorland and heath, and the right to graze them belongs to local farmers and commoners. In France, the gray horses of the Camargue roam the marshes of the Rhône delta. Konik horses graze nature reserves in the Netherlands, Poland and Britain, where they help keep wetlands open.

These herds look and act wild, and visitors should treat them that way: watch from a distance, never feed them and keep dogs under control. They are also very different from donkeys, which have their own feral populations; see our donkey profile.

Why are there so few truly wild horses?

Domestication was so successful that domestic horses replaced almost every other horse population. Ancient DNA shows that a single domestic lineage from the western Eurasian steppes spread across Asia and Europe after about 2200 BCE. Wild horses were hunted, lost their grazing land to farms and livestock, and mixed with domestic animals until they disappeared.

Some relatives of the horse resisted domestication altogether. Zebras, for example, were never tamed for large-scale use, for reasons explained in Why were zebras never domesticated?.