The horse family Equidae and the genus Equus evolved in North America before the species moved into the Eastern Hemisphere. The wild horse (Equus ferus) is a species of the genus Equus, its subspecies including the modern domesticated horse (Equus ferus caballus) the undomesticated tarpan (Equus ferus ferus), now extinct, and the endangered Przewalski's horse (Equus ferus przewalskii).
• The Przewalski's horse , also known as the Mongolian wild horse or Takhi, is native to Central Asia and the Gobi Desert. The Przewalski's horse was saved from the brink of extinction during the 1960s and was reintroduced successfully into the wild to two preserves in Mongolia. This endangered species can also be found in several zoos around the world.
• The tarpan or Eurasian wild horse was once native to Europe and western Asia. It became extinct in the late 19th century.
The Przewalski's horse and tarpan are the only known never-domesticated "wild" groups. There may have existed other subspecies of Equus ferus, they possibly being the wild ancestors of today’s domesticated horses.
The term "wild horse" is also used colloquially to refer to free-roaming herds such as mustangs in the United States, the brumby in Australia, and many others. Since all free-roaming horses now in the Americas descended from horses that were once domesticated in Europe, a more proper term is feral horses. Isolated populations of feral horses exist on all continents. These animals often referred to as "wild" horses also had domesticated ancestors, which may give rise to an argument that they are not truly "wild" in the biological sense.
Modern history of horses in North America starts with the Colonial Spanish horse.
The Colonial Spanish horse is the term used for a group of horse breeds descended from the original Iberian horse brought from Spain to the Americas. DNA testing showed the relatedness of Indian horses to the Spanish stock of the conquistadors. Those escaping to the wild formed first feral herds – original mustangs. In time there has been many crossbreeding in many feral horse herds, so new breeds and types were introduced (Arabians, Thoroughbreds..), contributing to the modern mustang. English word "mustang" comes from the Spanish word mestengo (or mesteño), meaning "wild, having no master.
Horses listed as of Colonial Spanish Horses include the following:
The Spanish Mustang, Banker horse, Carolina Marsh Tacky, Chickasaw horse, Choctaw horse
Mustangs considered to be Colonial Spanish strains: Kiger Mustang, Pryor Mountain Mustang, Sulphur Mustang, Abaco Barb.
At the beginning of 20th century, descendants of Spanish horses were on the brink of extinction. The Spanish Mustang is one of the first breeds developed in the 1900s in order to avert their extinction. Horses with a phenotype indicating Spanish ancestry were gathered from feral Mustang herds, Native American herds and ranch stock from all over the west.
Another iconic breed of feral horses with Spanish ancestry are Banker horses. About 400 Bankers inhabit the long, narrow barrier islands of North Carolina's Outer Banks. Descendants of domesticated Spanish horses they may have been brought to the Americas and abandoned on islands by explorers or might have survived shipwrecks forming feral herds. Seen as a part of North Carolina's coastal heritage, the Bankers have been allowed to remain on the barrier islands. Horses are managed by the National Park Service, the state of North Carolina, and several private organizations.
Although classified as feral horses, Bankers, being free-roaming, are often referred to as "wild" horses.
Horses are prey animals with a well-developed fight-or-flight response. Their instinct is to flee from danger, except in some situations, especially in cases where a foal is threatened, they stand their ground and defend themselves.
They are beautiful, agile and strong animals. Some breeds also have great endurance. All that makes them suited for a great number of tasks. That is why humans domesticated horses thousands of years ago, and they have been using them ever since. Breeding enables favoring certain genetic traits in horses, so there are breeds suited for hard work, others are for riding etc. Using selective breeding humans in attempt to improve traits in horses that extend from their wild ancestors.
Humans eliminated most of the predators from the life of the domestic horse, but their survival instinct endured. When frightened a horse will try to escape. If it is not possible, the horse will bite, kick and strike its way out of danger.
Horses are highly social herd animals preferring to live in a group.
This trait makes them prone to form relationships , not only with other horses, but other animals as well, including humans. Feral and wild horse "herds" consist of several separate, smaller groups or “bands” which share a territory.
Bands are harems, most of the times having only one adult male, but there are cases where up to 5 stallions are observed in a band. The total number of horses in a band ranges from 3 to 35. There is usually a single "herd" or "lead" stallion, and sometimes several less-dominant adult males. Other stallions can challenge a lead stallion. Stallions usually protect the rear of the herd and keep it together.
Although a herd stallion engages in herding and protective behavior, it is often a dominant mare that leads a wild or feral herd. She is tasked with a search for food and water, movement of the herd etc.
Recent studies have shown that herd leadership can be divided among several herd members, and that in some instances any individual can temporarily guide the herd.
Domesticated stallions, with human help, often mate with up to 60 mares, which is significantly more than it is possible in the wild. That figure can be up to 200 mares per year.
Horses communicate using vocalizations such as nickering, squealing or whinnying; touch, mutual grooming, smell and body language. They use their heads, feet and tails to communicate.
They can interpret the body language of other creatures, including humans, whom they view as predators. It is very important for humans to know how to approach a horse. If a horse senses fear, a horse might interpret that as a human submission, and might behave in a more dominant and aggressive fashion. Furthermore, if too much aggression is used on human part, a horse might feel in danger and will instinctively react to perceived threat.
For this reason it is important that humans can interpret a horse's body language and approach accordingly. Horses are creatures of habit and have an excellent long-term memory, which makes training extremely important to the horse. Horses can sleep both standing up and lying down.
Horses have a strong grazing instinct, preferring to spend most hours of the day eating forage.
There are many aspects of domesticated horse care. Horses, ponies, mules, donkeys and other domesticated equids require attention from humans for optimal health and long life.
Domesticated horses must have adequate living environment, must be fed, groomed, vaccinated, cared for...
In 1971 a federal law was passed that banned capturing, harming or killing free-roaming horses or burros on public land. The care and management of the wild horse herds on federal land was turned over to the Bureau of Land Management.
The BLM distinguishes between "herd areas" (HA) where feral horse and burro herds existed at the time the Wild and Free-Roaming Horses and Burros Act of 1971 has been passed, and "Herd Management Areas" (HMA) where the land is currently managed for the benefit of horses and burros. Wild, free-roaming horses and burros are found in 50 territories managed by United States Forest Service (USFS) and are also protected by the Act. Thirty-seven are managed by the USFS and 13 are managed in cooperation with the BLM. There are also some protected free-roaming equine populations found on lands governed by the National Park Service (NPS). Today there are around 270 HMAs in 10 states. As of 2016, there are around 67000 horses and burros managed by the BLM.