Feral horse

Free horses of domesticated horse ancestry
information on never domesticated horse species

A feral horse is a free roaming horse of domesticated stock. As such, a feral horse is not a wild animal in the sense of an animal without domesticated ancestors. However, some populations of feral horses are managed as wildlife, and these horses often are popularly called "wild" horses. Feral horses are descended from domestic horses that strayed, escaped, or were deliberately released into the wild and remained to survive and reproduce there. Away from humans, over time, these animals' patterns of behavior revert to behavior more closely resembling that of wild horses. Some horses that live in a feral state but may be occasionally handled or managed by humans, particularly if privately owned, are referred to as "semi feral". Feral horses live in groups called a herd, band, harem, or mob. Feral horse herds, like those of wild horses, are usually made up of small harems led by a dominant mare, containing additional mares, their foals, and immature horses of both sexes. There is usually one herd stallion, though occasionally a few less dominant males may remain with the group. Horse "herds" in the wild are best described as groups of several small bands who share the same territory. Bands are normally on the small side, as few as three to five animals, but sometimes over a dozen. The makeup of bands shift over time as young animals are driven out of the band they were born into and join other bands, or as young stallions challenge older males for dominance. However, in a closed ecosystem (such as the isolated refuges in which most feral horses live today), to maintain genetic diversity, the minimum size for a sustainable free roaming horse or burro population is 150–200 animals.

The best known examples of modern day "wild" horses are those of the American West. When Europeans reintroduced the horse to the Americas, beginning with the arrival of the Spanish conquistadors in the 15th century, some horses escaped and formed feral herds known today as mustangs. Isolated populations of wild horses occur in a number of places in the United States, including Assateague Island off the coast of Virginia and Maryland, Cumberland Island, Georgia, Vieques Island off the coast of Puerto Rico, and Sable Island off the coast of Nova Scotia, Canada. Some of these horses are said to be the descendants of horses that managed to swim to land when they were shipwrecked. Others may have been deliberately brought to various islands by settlers and either left to reproduce freely or abandoned when assorted human settlements failed. Many prehistoric horse species, now extinct, evolved in North America, but the wild horses of today are the offspring of horses that were domesticated in Europe. In the Western United States, certain bands of horses and burros are protected under the Wild and Free Roaming Horses and Burros Act of 1971. There are about 300,000 horses today in multiple land jurisdictions across the country, including tribal lands.

The only truly wild horses in existence today are Przewalski's horse native to the steppes of central Asia. A modern wild horse population (janghali ghura) is found in the Dibru Saikhowa National Park and Biosphere reserve of Assam, in north east India, and is a herd of about 79 horses descended from animals that escaped army camps during World War II.

In Portugal, a population of free ranging horses, known as garrano, lives in the northern mountain chains. In County Kerry, Ireland, wild bog ponies have been known since at least the 1300s. More than 700 feral wild horses live in the foothills of Cincar Mountain, between Livno and Kupres, Bosnia and Herzegovina, in an area of roughly These animals, which descend from horses set free by their owners in the 1950s, enjoy a protected status since 2010. In Sardinia lives the Giara Horse, a wild species which inhabits the Giara di Gesturi, a basaltic plateau in the southern central part of the island. The popolation is composed by about 700 horses.

Australia has the largest population in the world, with about 400,000 horses. The Australian name equivalent to the mustang is the brumby, descendants of horses brought to Australia by English settlers.

In the United Kingdom, herds of free roaming ponies live in apparently wild conditions in various areas, notably Dartmoor, Exmoor, Cumbria (Fell Pony), and the New Forest. Similar horse and pony populations exist elsewhere on the European continent. These animals, however, are not truly feral, as all of them are privately owned, and roam out on the moors and forests under common grazing rights belonging to their owners. A proportion of them are halter broken, and a smaller proportion broken to ride, but simply turned out for a while for any of a number of reasons (e. g., a break in training to allow them to grow on, a break from working to allow them to breed under natural conditions, or retirement). In other cases, the animals may be government owned and closely managed on controlled reserves. Camargue horse, in marshes of the Rhone delta, southern France. Dartmoor pony, England; predominantly domesticated, also lives in semi feral herds. Exmoor pony, England; predominantly domesticated, also lives in semi feral herds. Fell pony, predominantly domesticated, also lives in semi feral herds in northern England, particularly Cumbria. Gotlandsruss, lives in a semi feral herd in Lojsta Moor on the Swedish Island of Gotland. New Forest pony, predominantly domesticated, also lives in semi feral herds in the area of Hampshire, England. Pottok, predominantly domesticated, also lives in semi feral herds in the western Pyrenees. Dülmen pony, a German pony that lives in a wild herd in Westphalia with little help by humans. Shetland pony, Scotland; predominantly used for riding, driving, and pack purposes.

Feral populations are usually controversial, with livestock producers often at odds with horse aficionados and other animal welfare advocates. Different habitats are impacted in different ways by feral horses. Where feral horses had wild ancestors indigenous to a region, a controlled population may have minimal environmental impact, particularly when their primary territory is one where they do not compete with domesticated livestock to any significant degree. However, in areas where they are an introduced species, such as Australia, or if the population is allowed to exceed available range, there can be significant impacts on soil, vegetation (including overgrazing), and animals that are native species. Fertility control is also sometimes used, though it is expensive and has to be repeated on a regular basis.