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Domestic Horse
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Equidae
Genus: Equus
Species: E. ferus
Subspecies: E. f. caballus
Trinomial name
Equus ferus caballus[1]
Linnaeus, 1758

Horses are one of the oldest species of domesticated animals. While isolated domestication may have occurred as early as 10,000 years ago, the first clear evidence of widespread horse use by humans dates to around 2000 BC. Horses have changed the course of human history through their association with mankind: although other animals have also been our beasts of burden, and served to move us over the land before technology provided us with machines; horses have had particular influence on human warfare; it is the hooves of horses that thundered under the hordes of Genghis Khan and the Spanish Conquistadors. Since they were domesticated, selective breeding has resulted in many different types of horse. Domesticated horses can be ridden, usually with a saddle, or harnessed to pull objects like carriages or plows. In some cultures, horses are a source of food, providing meat and sometimes milk; in other cultures, it is taboo to eat them. In most countries today, horses are predominantly kept for leisure and sporting pursuits, although they are still used as working animals in some rural areas, particularly in less developed parts of the world.

History of the horse

By the Pleistocene era, as the horse adapted to a drier, prairie environment, the 2nd and 4th toes disappeared on all feet, and horses became bigger. These side toes were shrinking in Hipparion and have vanished in modern horses. All that remains are a set of small vestigial bones on either side of the cannon (metacarpal or metatarsal) bone, known informally as splint bones, which are a frequent source of splints, a common injury in the modern horse.


Wild species

For more information, see: Wild Horse.

Almost all the horses that are called wild are actually feral horses, animals whose ancestors domesticated but escaped or were abandoned, and survived to breed, often for generations. All of the horses running free in herds in North, South, and Central America, and the islands of the New World are feral and not wild. However, there is one breed of truly wild horses whose ancestors were never successfully domesticated.

Przewalski's Horse (Equus ferus przewalskii), a rare Asian species, is the only true wild horse alive today. Mongolians know it as the taki, while the Kyrghyz people call it a kirtag. Small wild breeding populations of this animal, named after the Russian explorer Przewalski, exist in Mongolia. [2] There are also small populations maintained at zoos throughout the world.

Feral horses

Free-roaming mustangs (Utah, 2005)

Wild animals, whose ancestors have never undergone domestication, are distinct from feral ones, who had domesticated ancestors but were born and live in the wild. Several populations of feral horses exist, including those in the western United States of America and Canada (often called "mustangs"), and in parts of Australia ("brumbies") and New Zealand ("Kaimanawa horses"). Isolated feral populations are often named for their geographic location: Namibia has its Namib Desert Horses; the Sorraia lives in Portugal; Sable Island Horses reside in Nova Scotia, Canada; and New Forest ponies have been part of Hampshire, England for a thousand years.

Studies of feral horses have provided useful insights into the behavior of ancestral wild horses, as well as greater understanding of the instincts and behaviors that drive "tame" horses.

Feral horses in the United States are mired in political controversy at the present time owing to the conflict for land resources and the tough decisions the Bureau of Land Management must make in cost-efficient and humane ways of controlling the population. Current methods include yearly roundups of feral populations and offer of a select number of mustangs for adoption to private owners and established Mustang rehabilitation programs. Currently the nature of the 'round up' raises concern among animal advocates on the points of the round up itself generally involving chasing a herd via helicopter into a pen, which results in injuries due to panic or stumbling, the arbitrary nature of the herd separation on the premise that members selected for auctions might be integral members of family groups, and finally in the nature of horses selected for euthanasia- often including those injured during the roundup. As a long-standing symbol of American freedom, feral horses have strong-voiced advocates and adversaries alike.

Health and Care of the horse

See also: Horse reproduction

Depending on breed, management, and environment, the domestic horse today has an average life expectancy of 25 to 30 years. A rare few domestic horses can live into their 40s, and, occasionally, beyond. The oldest verifiable record was "Old Billy," a horse that lived in the 19th century, believed to have lived to the age of 62.

Pregnancy lasts for 11 months and usually results in one foal (male: colt, female: filly). Twins are rare. Horses, particularly colts, may sometimes be physically capable of reproduction at approximately 18 months but in practice are rarely allowed to breed until a minimum age of 3 years, especially females. Horses four years old are considered mature, though the age of achieving full growth also varies by breed and by individual genetics. Females 4 years and over are called mares and males are stallions. A castrated male is a gelding.

Depending on maturity, breed, and the tasks expected, young horses are usually put under saddle and trained to be ridden between the ages of two and four, with three years being the most common practice. Although Thoroughbred and American Quarter Horse race horses are put on the track at as young as two years old in some countries (notably the United States of America), horses specifically bred for sports such as show jumping are generally not entered into top-level competition until the age of five or six because their bones and muscles are not properly developed, nor is their training complete. In the strenuous sport of endurance riding, horses are not allowed to compete until they are a full 60 months (five years) old. In some cases, such as the training of Andalusians or Lipizzans in classical dressage, training under saddle begins as late as four years and the horses are not considered ready for public performance until the age of nine or ten.

The size of horses varies by breed. The cutoff in height between what is considered a horse and a pony is always 14.2 or smaller hands (58 inches, 145 cm), though some smaller horse breeds are considered "horses" regardless of height. The Icelandic horse, renowned for its special gait called the tölt, would easily be considered a pony in most cultures as it stands an average of 13 to 14 hands, but is always referred to as a horse. Light horses such as Arabians, Morgans, Quarter Horses, Paints and Thoroughbreds usually range in height from 14.0 to 17.0 hands and can weigh up to 1300 lb (about 600 kg). Heavy or draft horses such as the Clydesdale, Belgian, Percheron, and Shire are usually at least 16.0 to 18.0 hands high and can weigh up to 2000 lb (about 900 kg). Ponies are no taller than 14.2 hands, but can be much smaller, down to the Falabella or Shetland, which can be the size of a large dog. The miniature horse is as small as or smaller than either of the aforementioned ponies but are considered to be very small horses rather than ponies despite their size. The difference between a horse and pony is not just a height difference. They have different temperaments, different conformation, and ponies often exhibit thicker manes, tails, and overall hair coat.

Horse behavior

For more information, see: Horse behavior.

Horses are prey animals with a well-developed Fight-or-flight instinct. Their first response to threat is to flee, although they are known to stand their ground and defend themselves or their offspring in cases where flight is not possible, such as when a foal would be threatened. Through selective breeding, some breeds of horses have been bred to be quite docile, particularly certain large draft horses. However, most light horse riding breeds were developed for speed, agility, alertness and endurance; natural qualities that extend from their wild ancestors.

Horses are herd animals, and become very attached to their species and to humans. They communicate in various ways, such as nickering, grooming, and body language. Some horses will become flighty, and hard to manage if they are away from their herd. This is called being "herd-bound." Additionally, despite having evolved as gregarious herd animals, many modern domestic horses become "barn sour" or "stall bound" meaning they are reluctant to leave the comfort of their stall and when taken out, for example, on a trail ride, pick up the pace considerably or even run when heading back in the direction of the barn.

Horses used for therapeutic purposes

For more information, see: Therapeutic horseback riding.

A form of physical therapy is Therapeutic horseback riding. People with both physical and mental disabilities have obtained medically beneficial results from riding. The movement of a horse strengthens muscles throughout a rider's body and promotes better overall health. In many cases, riding has also led to increased mobility for the rider and sometimes has helped injured people regain the ability to walk. Soldiers injured in warfare have been known to use this form of physical therapy to regain movement in limbs or simply become accustomed to prosthetic limbs. People who have cognitive or sensory disabilities benefit because riding requires attention, reasoning skills, and memory.

The benefits of equestrian activity for people with disabilities has also been recognized with the addition of equestrian events to the Paralympic Games.

"Equine-assisted" or "equine-facilitated" psychotherapy is a new but growing movement which uses horses as companion animals to assist people with mental illness. Actual practices vary widely due to the newness of the field; some programs include therapeutic riding. Non-riding therapies simply encourage a person to touch, speak to and otherwise interact with the horse. Even without riding, people appear to benefit from being able to connect to a horse on a personal level. People with mental illnesses can benefit from the interaction and relationships formed with both horses and people. Horses are also used in camps and programs for young people with emotional difficulties.

There also have been experimental programs using horses in prison settings. Exposure to horses appears to improve the behavior of inmates in a prison setting and help reduce recidivism when they leave. A correctional facility in Nevada has a successful program where inmates learn to train young mustangs captured off the range in order to make it more likely that these horses will find adoptive homes. Both adult and juvenile prisons in New York, Florida, and Kentucky work in cooperation with the Thoroughbred Retirement Foundation to re-train former racehorses as pleasure mounts and find them new homes.

Horses in warfare

For more information, see: War horse.

Horses were used in warfare for most of recorded history, dating back at least to the 19th century B.C. The advent of stirrups provided considerable technical advantage and greatly increased a warrior's leverage, to the point that troops without stirrups would have to dismount to fight. While mechanization largely has replaced the horse as a weapon of war, horses are still seen today in limited military uses, mostly for ceremonial purposes, or for reconnaissance and transport activities in areas of rough terrain where motorized vehicles are ineffective. Horses are also used to reenact historical battles; see Culture above. The training of the war horse has vestiges in the disciplines of classical dressage and eventing.


For more information, see: Horse gait.

All horses move naturally with four basic gaits; these are referred to as walk, trot ("English") or jog ("Western"), canter ("English") or lope ("Western"), and gallop.

Besides these basic gaits, additional gaits such as pace, slow gait, rack, fox trot and tölt can be distinguished. These special gaits are often found in specific breeds, and are referred to as "gaited" because they naturally possess additional "single-footed" gaits that are approximately the same speed as the trot but smoother to ride.

Technically speaking the so called "gaited horses" replace the standard trot which is a 2 beat gait with a four beated gait. (as opposed to the canter/lope and gallop which are three beated gaits) This can be clearly heard when shod horses are riding on the street. The anatomy of the trot consists of the lifting a front hoof and a rear opposite sided hoof at the same time. This can be seen vividly when watching lippizaners on parade, and is similar to a dog's trot. A four beated gait occurs when only one foot at a time lifts off, and hence is called a "running walk". In a manner of speaking this is like the front legs being operated independently of the rear. A true gaited horse will rarely, if ever, trot; gaited horse foals will gait from birth. A pace is a two beat gait where the animal moves the front and rear legs of one side at the same time, similar to an elephant. This produces a ride that is not as jarring up and down as a trot but has a definite side to side or rocking motion, this is considered an undesirable gait by people in the gaited horse trade.

A trot is an up and down action of the legs whereas the true gaited horse generally has some sort of circular motion to the front hooves (either a somewhat exaggerated forward circle, or in the case of the paso fino an outward winging motion from the knee down) and a sliding or shuffling motion to the rear hooves, when done perfectly this produces a gait that is as fast and oftentimes faster than a trot and smooth enough that the rider feels as though in an easy chair. Through training a gaited horse may effectively be rendered a 3 gaited horse with only the walk, the special gait (running walk, rack, foxtrot, etc), and the gallop. This does not diminish the speed of the horse, the animal just has no need to lope/canter due to the speed that it can perform its' special gait.

Horse breeds with additional gaits include the Tennessee Walking Horse with its running walk, the American Saddlebred with its "slow gait" and rack, the Paso Fino horse with the paso corto and paso largo and Icelandic horse which are known for the tölt. The Fox Trot is found in several gaited breeds, most notably the Missouri Foxtrotter while some Standardbreds, pace instead of trot.

The origin of modern horse breeds

Horses come in various sizes and shapes. The draft breeds can top 19 hands (76 inches, 2 metres) while the smallest miniature horses can stand as low as 5.2 hands (22 inches, 0.56 metres). The Patagonian Fallabella, usually considered the smallest horse in the world, compares in size to a German Shepherd Dog.

Different schools of thought exist to explain how this range of size and shape came about. One school, which we can call the "Four Foundations," described in the domestication section above, suggests that the modern horse evolved from multiple types of early domesticated pony and early domesticated horse; the differences between these types account for the differences in type of the modern breeds. A second school -- the "Single Foundation" -- holds only one breed of horse underwent domestication, and it diverged in form after domestication through human selective breeding (or in the case of feral horses, through ecological pressures). This question will most likely only be resolved once geneticists have finished evaluating the horse genome, analyzing DNA and mitochondrial DNA to construct family trees. See: Domestication of the horse.

In either case, modern horse breeds developed in response to the need of "form to function;" that is, the necessity to develop certain physical characteristics necessary to perform a certain type of work. Thus, light, refined horses such as the Arabian horse or the Akhal Teke developed in dry climates to be fast and with great endurance over long distances, while the heavy draft horse such as the Belgian developed out of a need to pull plows. Ponies of all breeds developed out of a dual need to create mounts suitable for children as well as for work in small places like mine shafts or in areas where there was insufficient forage to support larger draft animals. In between these extremes, horses were bred to be particularly suitable for tasks that included pulling carriages, carrying heavily-armored knights, jumping, racing, herding other animals, and packing supplies.

The Icelandic horse (pony-sized but called a horse) provides an opportunity to compare contemporary and historical breed appearances and behavior. Introduced by the Vikings into Iceland over one thousand years ago, these horses did not subsequently undergo the intensive selective breeding that took place in the rest of Europe from the Middle Ages onwards, and consequently bear a closer resemblance to pre-Medieval horses. The Icelandic horse is of small stature and has a four-beat gait called the "tolt", similar to the rack of the American Saddlebred.

Some countries specialize in breeding horses suitable for particular activities. For example, Australia, the United States, and the Patagonia region of South America are known for breeding horses particularly suitable for working cattle and other livestock. Germany produces Holsteiner and other Warmblood breeds that are used for dressage. Ireland is recognized for breeding hunters and jumpers. Spain and Portugal are known for the "Iberian horses", Andalusians (Pura Raza Española) and Lusitanos, used in high school dressage and bullfighting. Austria is known worldwide for its Lipizzaner horses, used for dressage and high school work in the famous Spanish Riding School in Vienna. The United Kingdom breeds an array of heavy draft horses and several breeds of hardy ponies, including the Dartmoor pony, Exmoor pony and Welsh pony. Both the United States of America and Great Britain are noted for breeding Thoroughbred race horses. Great Britain is well known for the bay haired Shire horse breed. The United States is also known for the Morgan and Quarter horse breeds. Russia takes great pride in breeding harness racing horses, a tradition dating back to the development of the Orlov Trotter in the 18th century.

Breeds, studbooks, purebreds, and landraces

For more information, see: Horse breeding.

Selective breeding of horses has occurred as long as humans have domesticated them. However, the concept of controlled breed registries has gained much wider importance during the 20th century. One of the earliest formal registries was General Stud Book for thoroughbreds[3], a process that started in 1791 tracing back to the foundation sires for that breed. These sires were Arabians, brought to England from the Middle East.

The Arabs had a reputation for breeding their prize Arabian mares to only the most worthy stallions, and kept extensive pedigrees of their "asil" (purebred) horses. Though these pedigrees were primarily transmitted via an oral tradition, written pedigrees of Arabian horses can be found that date to the 14th century. During the late Middle Ages, the Carthusian monks of southern Spain, themselves forbidden to ride, bred horses which nobles throughout Europe prized; the lineage survives to this day in the Andalusian horse or caballo de pura raza español.

The modern landscape of breed designation presents a complicated picture. Some breeds have closed studbooks; a registered Thoroughbred, Arabian, or Quarter Horse must have two registered parents of the same breed, and no other criteria for registration apply. Other breeds tolerate limited infusions from other breeds; for example, the modern Appaloosa must have at least one Appaloosa parent but may also have a Quarter Horse, Thoroughbred, or Arabian parent and must also exhibit spotted coloration to gain full registration. Still other breeds, such as most of the warmblood sport horses, require individual judging of an individual animal's quality before registration or breeding approval, but also allow outside bloodlines in if the horses meet the standard.

Breed registries also differ as to their acceptance or rejection of breeding technology. For example, all Jockey Club Thoroughbred registries require that a registered Thoroughbred be a product of a natural mating ('live cover' in horse parlance). A foal born of two Thoroughbred parents, but by means of artificial insemination or embryo transfer is barred from the Thoroughbred studbook. Any Thoroughbred bred outside of these constraints can, however, become part of the Performance Horse Registry.

On the other hand, since the advent of DNA testing to verify parentage, most breed registries now allow artificial insemination (AI), embryo transfer (ET), or both. The high value of stallions has helped with the acceptance of these techniques because they 1) allow a stallion to breed more mares with each "collection," and 2) take away the risk of injury during mating.

Hot bloods, warm bloods, and cold bloods

See also: List of horse breeds

Horses are mammals and as such are all warm-blooded creatures, as opposed to reptiles, which are cold-blooded. However, these words have developed a separate meaning in the context of equine description, with the "hot-bloods," such as race horses, exhibiting more sensitivity and energy, while the "cold-bloods" are heavier, calmer creatures such as the draft giants.

Hot bloods Arabian horses, whether originating on the Arabian peninsula or from the European studs (breeding establishments) of the 18th and 19th centuries, gained the title of "hot bloods" for their temperament, characterized by sensitivity, keen awareness, athleticism, and energy. European breeders wished to infuse some of this energy and athleticism into their own best cavalry horses. These traits, combined with the lighter, aesthetically refined bone structure of the Arabian, was used as the foundation of the thoroughbred breed.

The Thoroughbred is unique to all breeds in that its muscles can be trained for either fast-twitch (for sprinting) or slow-twitch (for endurance), making them extremely versatile breed. Arabians are used in the sport horse world almost exclusively for endurance competitions. Breeders continue to use Arabian sires with Thoroughbred dams to enhance the sensitivity of the offspring for use in equestrian sports. This Arabian/Thoroughbred cross is known as an Anglo-Arabian.

True hot bloods usually offer both greater riding challenges and rewards than other horses. Their sensitivity and intelligence enable quick learning with greater communication and cooperation with their riders. However, their intelligence also allows them to learn bad habits as quickly as good ones. Because of this, they also can quickly lose trust in a poor rider and do not tolerate inept or abusive training practices.

Cold bloods Muscular and heavy draft horses are known as "cold bloods", as they have been bred to have the calm, steady, patient temperament needed to pull a plow or a heavy carriage full of people. One of the most best-known draft breeds is the Belgian. The largest is the Shire. The Clydesdales, with their common coloration of a bay or black coat with white legs and long-haired, "feathered" fetlocks are among the most easily recognized. [4]

Warmbloods "Warmblood" breeds began when the European carriage and war horses were crossed with Arabians, Anglo-Arabians and Thoroughbreds. The term "warm blood" was originally used to mean any cross of heavy horses on Thoroughbred or Arabian horses. Examples included breeds such as the Irish Draught horse, and sometimes also referred to the "Baroque" horses used for "high school" dressage, such as the Lipizzaner, Andalusian, Lusitano and the Alter Real. Sometimes the term was even used to refer to breeds of light riding horse other than Thoroughbreds or Arabians, such as the Morgan horse. But today the term "warmblood" usually refers to a group of sport horse breeds that have dominated the Olympic Games and World Equestrian Games in Dressage and Show Jumping since the 1950s. These breeds include the Hanoverian, Oldenburg, Trakehner, Holsteiner, Swedish Warmblood, and Dutch Warmblood.

The list of horse breeds provides a partial alphabetical list of breeds of horse extant today, plus a discussion of rare breeds' conservation.


Genetic Anomalies

Horses are capable of expressing chimeric DNA. A Chimeric horse often has a brindle pattern in the coat, which in itself is rare enough. What the brindle pattern indicates in the case of a Chimeric horse, however, is two entirely unique DNA strands contained in one animal. Essentially, chimeric horses are formed when two non-identical twins fuse into one embryo in utero. As such, the offspring of a chimeric horse may test negative for parentage from a chimeric sire, depending on which sample the offspring is tested against.

General safety

Horses should never be approached from behind, for while they can see almost 360 degrees, the areas directly behind them and directly in front of their nose are 'blind spots' and surprising a horse from behind can result in being kicked.

When leading a horse, a lead rope is key to maintaining safety in an unforeseen circumstance, giving you distance from, but some degree of control of the horse. Traditionally horses are led with the person on the left-hand side, and the horse on the right, slightly behind, so the horse's nose or shoulder is even with your shoulder. The lead rope should be held with the excess folded inside the palm of the hand and never in a loop around the hand- a sudden motion from the horse can cause the lead rope to whip around at an incredible speed, strong enough to break delicate finger and hand bones.

Horses should not be left standing with a lead rope dangling from the halter, at the risk the horse will step on it and panic, seriously injuring himself and possibly others.

Always wear hard-toed shoes in the presence of horses, to protect your toes if your foot is stepped on.

Generally, it is recommended to move slowly and calmly around horses. Even a horse that knows you and is generally quiet can become surprised or fearful.

Saddling and mounting

The common European practice and tradition of saddling and mounting the horse from the left hand side is sometimes said to originate from the practice of right-handed fighters carrying their sheathed sword on their left hip, making it easier to throw their right leg over the horse when mounting, and sometimes it is regarded as a superstition. However, several other explanations are equally plausible.

Horses can be mounted bareback with a vault from the ground, by grabbing the mane to provide leverage as a rider makes a small jump and scrambles up onto the horse's back (an awkward but popular method used by children), or by "bellying over", a technique which involves placing both hands side by side on the horse's back, jumping up so that the rider lays belly down on the horse's back, and swinging the leg over to sit astride. Some people prefer to bareback pads, which are basically sheepskin cushions, when riding bareback, especially on old, under-nurished or bony horses.

In actual practice, however, most bareback riders use a fence or mounting block, or another object which can be stood upon to be able to simply slide onto the horse's back. This method is more convenient for both horse and rider, as the horse does not like someone "hiking' onto their back, and the "hiking" can be found to be very difficult for the rider, especially if the horse is tall or large.


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