Article: When Is "Wild" Actually "Feral"?

The takhi is the only true wild horse left in the world. The so-called “wild” horses that abound in Australia and North America are actually feral. A domestic animal becomes "feral" simply by fending for itself when left in the wild, without being helped or managed by humans in any way. If it finds others of its own species, reproduces, and the offspring also fend for themselves in the wild, the result is a feral population.


Feral horses do live in self-sustaining populations in the wild, though they—or their ancestors—once belonged to domestic populations that were bred, for thousands of years, for ease of handling. The truly wild horses of the Copper Age were probably tougher and more aggressive than today's feral stock. The takhi, having never been genetically manipulated, has a reputation for being hard to handle and almost impossible to ride.

More Alike than Different

Both domestic and feral populations of the common horse, as well as the reintroduced populations of takhi, share many distinctive traits. Domestic horses readily adapt to life in the wild, and feral herds show survival traits typical of animals that have never been domesticated. On the basis of observations of captive populations of takhi, the physiology and social organization of feral herds of the common horse and wild populations of takhi appear much the same. The horses range in small bands of 5 to 15 animals, consisting of a dominant stallion, his harem of mares, and their offspring.

The exchange between domestic and feral horse populations is ongoing. A feral stallion will instinctively attempt to recruit domesticated mares for his harem, and mares will readily join a feral herd. Conversely, feral horses are sometimes captured and returned to the domestic herd.

Feral Horses are Everywhere

Since the horse was first domesticated, populations of feral horses have existed over much of the world—in Europe, Iran, Greece, New Zealand, Colombia, Hispaniola, Galapagos, and other oceanic islands, among other places. Historically, these free-ranging animals have been given romantic names like the mustang in North America, the brumby in Australia, and the cimarron in South America. All are descended from stock of Equus caballus that escaped from indigenous horsemen, ranchers, farmers, or miners.

Today Australia is home to the largest number of feral horses—between 128,000 and 205,000 brumbies. (We know there were never any truly wild horses in Australia because all native mammals are either egg-laying, marsupials, small rodents, or bats. Even the famed dingo is a feral animal: a descendant of aborigines' dogs that ran wild.) Other well-known feral horse populations include:

  • The gray horses of the Camargue, the marshy Rhone River delta in southern France. Descended from Arab horses that ran wild during the Roman occupation of Gaul, these horses have developed hard, flat hooves that spread their weight across the swampy ground.
  • Herds of dark-brown horses in Sweden's mixed tundra and forest are feral.
  • Iceland is home to populations of feral ponies.
  • Nine breeds of semi-wild ponies that live in the British Isles. Among the best known are England's New Forest and Exmoor ponies.
  • The "wild" horses of Assateague, a barrier island off the mid-Atlantic United States.
What About the Mustang?

The horse was reintroduced to the New World by Columbus in 1493. Hernando Cortez, the Spanish conqueror of Mexico, is generally credited with being the first to land horses on the North American mainland. When animals escaped from an expedition north from Mexico led by Francisco Vasquez de Coronado in 1543—accounts of the exact date and number of horses vary—they formed the basis of the continent's first feral horse population. These became known as “mustangs,” from the Spanish word “mesteño,” meaning “wild.”

Between 1600 and 1850, vast herds of mustangs, totaling millions of horses, ranged from the Mississippi River to the Pacific Ocean. Their number was constantly added to by new escapees and animals deliberately turned loose. Native Americans, who had become acquainted with the horse in Spanish frontier settlements, soon learned to break and ride mustangs. By the late eighteenth century, these horses formed the basis of the Plains Indians’ warrior and buffalo-hunting cultures.

But with the development of modern ranching, these emblems of the American West came to be regarded as pests that competed with domestic stock and depleted the range. Between the 1920s and the 1950s, mustangs were rounded up and slaughtered without limit. Many were sold for pet food. Eventually, though, the tide turned. In 1971, when about 17,000 feral horses were left, the US Wild Free-Roaming Horse and Burro Act mandated the protection of these animals as a “national heritage species.” Herds are now increasing, with Nevada home to the largest population. As to what percentage are descendants of the original mustangs, and which are more recent domestic escapees . . . nobody knows.