This page is about ungulate mammals. For other meanings, see Horse (disambiguation).

Domestic Horse
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Perissodactyla Family: Equidae Genus: Equus Species: caballus
Binomial name
Equus caballus

The Horse (Equus caballus) is a large ungulate mammal, one of the seven modern species of the genus Equus. It has long played an important role in transportation; whether ridden, or when pulling a chariot, carriage, horse-drawn boat, stagecoach, tram, etc.; also as plough horse, etc. as well as for food; see also domestication of the horse. Until the mid 20th century, armies used horses extensively in warfare: soldiers still call the groups of machines that now take the place of the horse on the battlefield "cavalry" units, sometimes keeping traditional names (Lord Strathcona's Horse, etc.)

Evolution of the horse

The evolution of the horse from the very early (around 55 million years ago) Hyracotherium or eohippus to the wild equids listed below, is well understood in comparison to our understanding of the evolutionary succession of most animals. By natural selection, the toes of early horse ancestors reduced to the single central toe which forms the hoof of the modern equine. The opposite being animals with 'cloven' hooves (2 toes), like cows, pigs and sheep. Vestiges of other toes remain as the splint bones, the callous-like "chestnuts" on the inner sides of all four legs, and the "ergots" hidden in the hair of the underside of the fetlock joint. Rare instances of modern horses with true extra toes have been cited by evolutionary biologist Stephen Jay Gould as evidence that minor genetic mutations can reintroduce ancestral features (in his 1983 book Hen's Teeth and Horse's Toes ISBN 0393311031 ).

In nature, horses are prey animals. They have a natural tendency to flee from danger, though they will fight if cornered. Their eyes are placed to the side of the head, giving them a wide view while grazing (slightly less than 180 degrees to each side, overlapped in front and leaving a blind spot in the rear). Even domesticated horses are easily startled and must be carefully introduced to strange objects and situations to be able to ride them safely.

Horses live in family groups in primarily grassland habitats. These normally consist of a mature stallion, his harem of '[about how many?]' mares, and the mares' offspring. Once young males reach breeding age and begin to attempt to breed with mares or to challenge the herd stallion, the latter drives them out of the herd to form "bachelor bands" with other young stallions. Usually not until a stallion reaches 7 or 8 years old does he stand a real chance of acquiring mares, eventually becoming, if successful in the attempt, a "band stallion", i.e. having a harem of his own, having separated female equids from another stallion's band.

An alpha mare dictates the direction in which a family herd travels, while the stallion brings up the rear, "herding" his family. Recently, researchers have observed that a form of democracy appears to exist among horses. For instance, if the majority of the herd wants to stop and eat, the whole herd follows suit.

The earliest evidence for the domestication of the horse comes from Central Asia and dates to about 3,000 BCE. Competing theories exist about the time and place of domestication. However, wild species continued into historic times, including the Forest Horse, Equus caballus silvaticus (also called the Diluvial Horse); it is thought to have evolved into Equus caballus germanicus, and may have contributed to the development of the heavy horses of northern Europe, such as the Ardennais.

The Tarpan, Equus caballus gmelini, became extinct in 1880. Its genetic line is lost, but a substitute has been recreated by "breeding back", crossing living domesticated horses that had features selected as primitive, thanks to the efforts of the brothers Lutz Heck (director of the Berlin zoo) and Heinz Heck (director Tierpark Munich Hellabrunn). The resulting animal is more properly called the Wild Polish Horse or Konik.

Only one true wild-horse species survives: Przewalski's Horse, Equus caballus przewalskii przewalskii Polaikov, a rare Asian species. Mongolians know it as the taki, while the Kirghiz people call it a kirtag. Wild populations exist in Mongolia; see: http://www.treemail.nl/takh/.

Wild vs. feral horses

One can distinguish between wild animals, whose ancestors have never undergone domestication, and feral animals, who had domesticated ancestors but who now live in the wild. Several populations of feral horses exist, including those in the West of the United States (often called "mustangs") and in parts of Australia (called "brumbies") and in New Zealand called "Kaimanawa horses". These feral horses may provide useful insights into the behavior of their ancestral wild horses.

The Icelandic horse (which has the size of a pony but is referred to as a horse) is an interesting breed from a historic and behavioural point of view. Introduced by the Vikings into Iceland, Icelandic horses have missed out on the intensive selective breeding that has taken place in Europe from the middle ages until now, giving us a picture of what horses looked like and behaved like in those times. The Icelandic horse has a four-beat gait called the "tolt", which equates to the rack exhibited by several American gaited breeds.

Other equids

Other members of the horse family include zebras, donkeys, and hemionids. The Donkey, Burro or Domestic Ass, Equus asinus, like the horse, has many breeds. A mule is a hybrid of a male ass and a mare and is infertile. A hinny is the less common hybrid of a female ass and a stallion. Recently breeders have begun crossing various species of zebra with mares or female asses to produce "zebra mules"—zorses and zedonks. This will probably remain a novelty hybrid as these individuals tend to inherit some of the nervous, difficult nature of their zebra parent.

Main article: Horses as food

Humans rarely breed horses for use as food, but use the meat of old, injured or discarded animals in many places. Meat from (injured) horses that vets have put down with a lethal injection is not used for consumption: the carcasses of such animals are cremated. In 2001, people consumed an estimated 153,000 tonnes of horse meat worldwide. In France specialized butcher shops (boucheries chevalines) sell horsemeat, as ordinary butcher shops do not have the right to deal in it. The eating of horse meat is a food taboo and abhorrent to some people in some parts of the world, such as the United Kingdom and the US, and sometimes even illegal. In other parts of the world, horse meat has the stigma of being something poor people eat and is seen as a cheap substitute.

In the English-speaking world, horses are measured in hands. One hand is 4 inches, or about 0.10 meter. Adult horses can range in size from 5 hands (a very small miniature horse or falabella) to over 18 hands. The convention is: 15.2 hh means 15 hands, 2 inches in height, measured at the highest point of the withers.

Horses are usually distinguished from ponies purely according to size: a horse stands 14.2 hh (58 inches, 1.47 meters) or higher, a pony is an adult equine less than 14.2 hh. Thus, normal variations can mean that a horse stallion and horse mare can become the parents of an adult pony. There is however a distinct set of characteristic pony traits that evolved in northwest Europe and further evolved in the British Isles, muddying the issue of whether "pony" should be used to describe a size or a type. Shetland ponies are considered by many as the archetypical pony, with its proportions very different from horses. Several small breeds are called horses or ponies interchangeably, including the Icelandic, Fjord, and Caspian. Breeders of miniature horses favor that name because they strive to reproduce horse-like conformation in a very small size, even though their animals are undeniably descended from ponies.

Words for gaits

There are four basic gaits that all horses move in naturally:

• The walk - a "four beat" gait in which a horse must have three feet on the ground and only one foot in the air at any time. Progression is either hind leg, then the foreleg on the same side, then the oposite hind leg, then the remaining foreleg.
• The trot - a "two beat" gait in which a foreleg and opposite hindleg touch the ground at the same time. These are often called diagonals. In this gait, each leg bears weight separately, making it ideal to check for lameness, or stiffness in the joints.
• The canter - A "three beat" gait in which a foreleg and opposite hindleg strike the ground together, and the other two legs strike separately. Progression is one foreleg, then a period of suspension, then the opposite hind leg strikes, then the oppposite two legs. When cantering in a straight line, it does not usually matter which foreleg (or leading leg) goes first, but both should be given equal time as the horse may become "one-sided" or develop a reluctance to canter on a specific leg. In an enclosed area, the inside leg (the one nearest to the middle of the area) should lead, as this prevents the horse from "falling in".
• The gallop - Another "four beat" gait which follows a similar progression to the canter, except the two paired legs land separately, the hind leg landing slightly before the foreleg. The gallop can also have a leading leg, and the same rule applies in that each leg must be given equal time to lead.

There are various artificial gaits that have been developed for reasons such as appearance, and to improve the riding or driving quality.

For details, see Horse gaits.

Words relating to horses

• horse - adult equine of either sex over 14.2 hh (58 inches, 1.47 meters)
• pony - equine 14.2 hh or less (58 inches, 1.47 meters)
• mare - adult female horse
• stallion - adult, uncastrated male horse
• gelding - adult, castrated male horse
• foal - infant horse of either sex
• filly - female horse from birth to sexual maturity (about 24 months)
• colt - male horse from birth to sexual maturity (about 24 months)

• charger - a mediaeval war horse
• cob - any short-legged, stout variety, intended for heavy riders
• destrier - a heavy, strong mediaeval war horse
• draught horse - heavy, muscular beast of burden
• garron - small and disdained horse
• hack or hackney - a horse, especially an old and tired one, used for driving or riding
• jennet - a small horse, particularly a Spanish one
• nag - small horse or pony used for riding (uncomplimentary term)
• shelt - a Shetland pony

In horse-racing the definitions of colt, filly, mare, and horse differ from those given above. In thoroughbred racing, a colt is defined as a male horse less than five years old and a filly is a female horse less than five years old; in harness racing colts and fillies are less than four years old. Horses older than colts and fillies become known as horses and mares.

Words relating to horse anatomy

• withers - the highest point of the shoulder seen best with horse standing square and head slightly lowered. The withers are formed by the tops of the two shoulder blades and the space between them.
• mane and forelock - long and relatively coarse hair growing from the dorsal ridge of the neck, lying on either the left or right side of the neck, and the continuation of that hair on the top of the head, where it generally hangs forward. (See illustration)
• Dock - the point where the tail connects to the rear of the horse.
• Flank - Where the hind legs and the stomach of the horse meet.
• Pastern - Kind of like the ankle of the horse.
• Fetlock - The connection between the coronet and the pastern.
• Coronet - The part of the hoof that connects the hoof to the fetlock.
• Cannon - Kind of like the shin of the horse.
• Muzzle - the chin, mouth, and nostrils make up this on the horse's face.
• Crest - the point on the neck where the mane grows out of.
• Pole - the point or top of the head right in between the ears.

Horses exhibit a diverse array of coat colors and distinctive markings, and a specialized vocabulary has evolved to describe them. In fact, it is often more likely for one to refer to a horse in the field by his or her coat color than breed or gender. Coat colors include:

• Albino (white with pink eyes--very rare)
• Appaloosa (a breed, but usually a white horse with small dark spots, or a dark horse with a large white area over the haunches)
• Bay (dark red to deep brown)
• Brown (black with brown muzzle)
• Black
• Buckskin
• Chestnut
• Dapple (not a color but a pattern of shiny circles on the horse's coat, usually signifying peak health)
• Dun
• Fleabitten (not a color, but refers to usually red hairs flecked in the coat of a gray horse)
• Gray
• Grullo
• Paint (both tobiano and overo; also tovero)
• Oddbald
• Palomino
• Piebald
• Roan (often classified with gray; classically refers to a mixture of chestnut and white hairs, while a gray is a mixture of brown and white hairs)
• Skewbald
• Sorrel (in some registries this term is used to indicate a light chestnut)

Markings include:

On the face:

• Star
• Snip
• Stripe
• Blaze
• White Face (sometimes called Bald Face)

On the legs:

• Coronet
• Pastern
• Sock
• Stocking

Elsewhere:

• Cowlicks (hair whorls)--can occur on any part of the animal

Horses come in various sizes and shapes. The draft breeds can top 20 hands (80 inches, 2.03 meters) while the smallest miniature horses can stand as low as 5.2 hands (22 inches, 0.56 meters). The Patagonian Fallabella, usually considered the smallest horse in the world, compares in size to a German Shepherd Dog. These differences relate to breed, not to species: the individuals could interbreed.

Several schools of thought exist to explain how this range of size and shape came about. These schools grew up reasoning from the type of dentition and from the horses' outward appearance. One school, which we can call the "Four Foundations", suggests that the modern horse evolved from two types of early domesticated pony and two types of 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). Finally, certain geneticists have started evaluating the DNA and mitochondrial DNA to construct family trees. See: Domestication of the horse

Breeds, studbooks, purebreds and landraces

The idea of a "purebred" animal gained importance in Europe during the 19th century but selective breeding has occurred almost everywhere man has kept horses. The Arabs had a reputation for breeding their prize mares to only the most worthy stallions, and kept extensive pedigrees of their "asil" (purebred) horses. 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 or caballo de pura raza español.

The modern landscape of breed designation presents a complicated picture. Some breeds have closed studbooks; a registered Thoroughbred or Arabian must have two registered parents of the same breed, and no other criteria for registration apply. Other breeds tolerate limited infusions from other breeds—the modern Appaloosa for instance 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 sporthorses, require individual judging of an individual animal's quality before registration or breeding approval.

Hotbloods, warmbloods, and coldbloods

The Arabian horses, whether originating on the Arabian peninsula or from the European studs (breeding establishments) of the 18th and 19th century, are termed "hotbloods", for their fiery temperaments. (Some include the thoroughbred in the "hotblood" category.) The slow, heavy draft horses are termed "coldbloods" as they usually posess a quite calm temperament. The term "warmbloods" covers everything else, but the term also specifically refers to the European breeds, such as the Hanoverian, that have dominated dressage and show jumping since the 1950s. True warmbloods usually offer greater riding challenges than other horses, especially the coldblood. They show more excitability, and often more dominance; and the longer you ride them, the more excited they become, instead of getting tired.

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

Horses today

The invention of the internal combustion engine and the tractor reduced the utility of the horse in agriculture, although working teams still exist, in particular in specialty forestry. Mounted police still use working horses as a mainstay in riot control.

Racing in all its forms

The desire to see which horse is fastest seems to be an innate human feature. Horse-racing today can be divided into racing short distances under saddle on a track: flat racing or the thoroughbred horse race. Thoroughbreds are the most famous of the racing breeds, but Arabians, quarter horses, and Appaloosas are also raced on the flat in the United States. Quarter horses were traditionally raced for a quarter mile, hence the name. Steeplechasing is racing on a track, where the horses also jump over obstacles. This is most popular in the United Kingdom. Standardbred trotters and pacers are raced in harness with a sulky or racing bike. In France they are also raced under saddle. Endurance riding, a sport whose top ranks are dominated by the Arabian, is very popular in the United States and Europe, race lengths ranging from 20 to 100 miles.

The traditional competitions of Europe

The first three of the following count as Olympic disciplines:

• Dressage ("training" in French) involves the progressive training of the horse to a high level of impulsion, collection, and obedience. The goal of competitive dressage is to show the horse carrying out, on request, the natural movements that it performs without thinking while running loose.

• Show jumping comprises a timed event judged on the ability of the horse and rider to jump over a series of obstacles, in a given order and with the fewest refusals or knockdowns of fence rails, which (for safety), sit in shallow cups. At the Grand Prix level fences may reach a height of as much as 6 feet.

• Eventing, combined training, horse trials, "the Military," or "the complete test" as its French name translates, puts together the obedience of dressage with the athletic ability of show jumping, the fitness demands of a long endurance phase (a.k.a. "roads and tracks") and the "cross-country" jumping phase.

• Polo is a team game played on horseback. The object is to use a long handled mallet to drive a ball on the ground into the opposing teams goal while the opposing team defends their goal.

• Huntseat riding is the show discipline derived from the English foxhunting style. In the modern show ring hunters show "on the flat" at the walk, trot, and canter, and "over fences" where (unlike show jumpers) they receive credit for the rider's good position and the horse's smooth performance. A good show hunter is safe, willing, and careful over fences.

• Saddleseat, Park, or English Pleasure riding is a uniquely American discipline developed to show to best advantage the extravagantly animated movement of high-stepping gaited breeds such as the American Saddle Horse and Tennessee Walker. Arabians and Morgans are also commonly shown saddleseat in the United States.

Western riding

Dressage, jumping and cross-country offer forms of what Americans refer to as 'English riding'. Western riding evolved stylistically from traditions brought to the Americas by the Spanish, and its skills stem from the working needs of the cowboy in the American west. A main differentiating factor comes from the need of the cowboy to rope cattle with a lariat (or lasso). The cowboy must control the horse with one hand, and use the lariat with the other hand. That means that horses must learn to neck rein, that is, to respond to light pressure of the slack rein against the horse's neck. Once the cowboy has twirled the lariat and thrown its loop over a cow's head, he must snub the rope to the horn of his saddle. For roping calves, the horse learns to pull back against the calf, which falls to the ground, while the cowboy dismounts and ties the calf's feet together so that he can be brand it, treat it for disease, and so on. Working with half-wild cattle, frequently in terrain where one cannot see what lurks behind the next bush, means the ever-present very great danger of becoming unseated in an accident miles from home and friends.

These multiple work needs mean that cowboys require different tack, most notably a curb bit (usually with longer bars than an English equitation curb or pelham bit would have) which works by leverage, long split reins (the ends of which can serve as an impromptu quirt) and a special kind of saddle. The Western saddle has a very much more substantial frame (traditionally made of wood) to absorb the shock of roping, a prominent pommel surmounted by a horn (a big knob for snubbing the lasso after an animal has been roped), and, frequently, tapaderos ("taps") covering the front of the stirrups to prevent the cowboy's foot from slipping through the stirrup in an accident so that he might be dragged behind a frightened horse. The cowboy's boots, which have high heels of an uncommon shape, are also designed specifically to prevent the cowboy's foot from slipping through the stirrup.

Technically, the differences between 'English' and Western riding are smaller than most people think.

The outfit of competition Western rider is different from the dressage or 'English' rider. While in dressage all riders wear the same to prevent distraction from the riding itself, show in the form of outfit (and silver ornaments on saddle and tack) is part of Western riding. The riders must wear: cowboy boots, jeans, a shirt with long sleeves, and a cowboy hat. The choice of color is free. Things such as bolo ties, belt buckles, (shiny) spurs are optional.

Competitions exist in the following forms:

• Western pleasure - the rider must show the horse in walk, jog (a slow, controlled trot), trot and lope (a slow, controlled canter). The horse must remain under control with minimal force being directed through the reins and otherwise with minimal interference from the rider.

• Reining - considered by some the "dressage" of the western riding world, reining requires horse and rider to perform a precise pattern consisting of canter circles, rapid "spins" (a particularly athletic turn on the haunches), and the sliding stop which is executed from a full gallop.

• Cutting: more than any other, this is the event which highlights the "cow sense" prized in stock breeds such as the Quarter horse. The horse and rider select and separate a calf out of a small group. The calf then tries to return to its herdmates; the rider loosens the reins and it's entirely the horse's job to keep the calf separated, a job the best do with relish, savvy, and style. The cutter is awarded points by a jury.

• Team penning: a popular timed event in which 3 to 5 marked steers must be selected out of a herd and driven into a small pen by a team of 3 riders. The catch is that the gate to the pen cannot be closed till all the cattle (and only the intended cattle) are inside.

• Trail class: in this event, the rider has to maneuver the horse through an obstacle course in a ring. Speed is not important, but total control of the horse is. The horses have to move sideways, make 90 degree turns while moving backwards, a fence has to be opened and/or closed while mounted, and more such maneuvers relevant to everyday ranch or trail riding tasks are demonstrated.

• Barrel racing and pole bending: the timed speed/agility events of rodeo. In a barrel race, horse and rider gallop around a cloverleaf pattern of barrels, making agile turns without knocking the barrels over. In pole bending, horse and rider gallop the length of a line of six upright poles, turn sharply and weave through the poles, turn again and weave back, and gallop back to the start.

• Steer wrestling: Europe does not allow this activity because of animal welfare concerns, but it occurs in the United States of America, usually at rodeo events. While riding, the rider jumps off his horse onto a steer and 'wrestles' it to the ground.

• Roping: also banned in Europe. In calf roping, the rider has to catch a running calf by the neck with a lasso, stop the animal in its tracks, rapidy dismount the horse and immobilize the calf by tying three of its legs together. In team roping, one horse and rider lassos a running steer's horns, while another horse and rider lassos the steer's two hind legs.

• Bronc riding (riding a bucking "wild" horse for a timed duration) counts as a separate event, not considered part of Western riding as such. It consists of bareback bronc riding and of saddle bronc riding.

Other horse sports

• Horseback riding
• Fox hunting
• Horse hacking
• Horse show
• Rodeo
• Jousting
• Cavalry
• Rapa das bestas
• Bullfighting (rejoneo)

Authoritative sources of information

Book of Horses: A Complete Medical Reference Guide for Horses and Foals, edited by Mordecai Siegal. (By members of the faculty and staff, University of California, Davis, School of Veterinary Medicine.) Harper Collins, 1996.

The horse features in the 12-year cycle of animals which appear in the Chinese zodiac related to the Chinese calendar. See: Horse (Zodiac).