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The horse (''Equus ferus caballus'') is a
domesticated Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. A ...
, one-toed, hoofed mammal. It belongs to the taxonomic family
Equidae Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. All extant species are in the genus '' Equus'', ...
and is one of two extant subspecies of ''Equus ferus''. The horse has
evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
over the past 45 to 55 million years from a small multi-toed creature, ''
Eohippus ''Eohippus'' is an extinct genus of small equid ungulates. The only species is ''E. angustidens'', which was long considered a species of ''Hyracotherium''. Its remains have been identified in North America and date to the Early Eocene (Ypresian ...
'', into the large, single-toed animal of today. Humans began domesticating horses around 4000 BCE, and their
domestication Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. ...
is believed to have been widespread by 3000 BCE. Horses in the subspecies ''caballus'' are domesticated, although some domesticated populations live in the wild as
feral horse 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 ...
s. These feral populations are not true
wild horse The wild horse (''Equus ferus'') is a species of the genus ''Equus'', which includes as subspecies the modern domesticated horse (''Equus ferus caballus'') as well as the endangered Przewalski's horse (''Equus ferus przewalskii''). The Europea ...
s, as this term is used to describe horses that have never been domesticated. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from
anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...
to life stages, size,
colors Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associa ...
, markings,
breeds A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slight ...
,
locomotion Locomotion means the act or ability of something to transport or move itself from place to place. Locomotion may refer to: Motion * Motion (physics) * Robot locomotion, of man-made devices By environment * Aquatic locomotion * Flight * Locomo ...
, and behavior. Horses are adapted to run, allowing them to quickly escape predators, and possess an excellent
sense of balance The sense of balance or equilibrioception is the perception of balance and spatial orientation. It helps prevent humans and nonhuman animals from falling over when standing or moving. Equilibrioception is the result of a number of sensory syste ...
and a strong
fight-or-flight response The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...
. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down, with younger horses tending to sleep significantly more than adults. Female horses, called
mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than fo ...
s, carry their young for approximately 11 months and a young horse, called a foal, can stand and run shortly following birth. Most domesticated horses begin training under a
saddle The saddle is a supportive structure for a rider of an animal, fastened to an animal's back by a girth. The most common type is equestrian. However, specialized saddles have been created for oxen, camels and other animals. It is not k ...
or in a harness between the ages of two and four. They reach full adult development by age five, and have an average lifespan of between 25 and 30 years. Horse breeds are loosely divided into three categories based on general temperament: spirited "hot bloods" with speed and endurance; "cold bloods", such as
draft horse A draft horse (US), draught horse (UK) or dray horse (from the Old English ''dragan'' meaning "to draw or haul"; compare Dutch ''dragen'' and German ''tragen'' meaning "to carry" and Danish ''drage'' meaning "to draw" or "to fare"), less oft ...
s and some
ponies A pony is a type of small horse ('' Equus ferus caballus''). Depending on the context, a pony may be a horse that is under an approximate or exact height at the withers, or a small horse with a specific conformation and temperament. Compared ...
, suitable for slow, heavy work; and "
warmblood Warmbloods are a group of middle-weight horse types and breeds primarily originating in Europe and registered with organizations that are characterized by open studbook policy, studbook selection, and the aim of breeding for equestrian spor ...
s", developed from crosses between hot bloods and cold bloods, often focusing on creating breeds for specific riding purposes, particularly in Europe. There are more than 300 breeds of horse in the world today, developed for many different uses. Horses and humans interact in a wide variety of sport competitions and non-competitive recreational pursuits as well as in working activities such as police work,
agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people t ...
, entertainment, and
therapy A therapy or medical treatment (often abbreviated tx, Tx, or Tx) is the attempted remediation of a health problem, usually following a medical diagnosis. As a rule, each therapy has indications and contraindications. There are many different ...
. Horses were historically used in warfare, from which a wide variety of riding and
driving Driving is the controlled operation and movement of a vehicle, including cars, motorcycles, trucks, buses, and bicycles. Permission to drive on public highways is granted based on a set of conditions being met and drivers are required to f ...
techniques developed, using many different styles of equipment and methods of control. Many products are derived from horses, including meat,
milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modula ...
, hide, hair, bone, and pharmaceuticals extracted from the urine of pregnant mares. Humans provide domesticated horses with food, water, and shelter as well as attention from specialists such as
veterinarian A veterinarian (vet), also known as a veterinary surgeon or veterinary physician, is a medical professional who practices veterinary medicine. They manage a wide range of health conditions and injuries in non-human animals. Along with this, vet ...
s and
farrier A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary. A farrier combines some blacksmith's skills (fabricating, adapting, and adj ...
s.


Biology

Specific terms and specialized language are used to describe
equine anatomy Equine anatomy encompasses the gross and microscopic anatomy of horses, ponies and other equids, including donkeys, mules and zebras. While all anatomical features of equids are described in the same terms as for other animals by the Internatio ...
, different life stages, and colors and breeds.


Lifespan and life stages

Depending on breed,
management Management (or managing) is the administration of an organization, whether it is a business, a nonprofit organization, or a Government agency, government body. It is the art and science of managing resources of the business. Management includ ...
and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was " Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, who had been listed in ''
Guinness World Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
'' as the world's oldest living pony, died in 2007 at age 56. Regardless of a horse or pony's actual birth date, for most competition purposes a year is added to its age each January 1 of each year in the Northern Hemisphere and each August 1 in the Southern Hemisphere. The exception is in endurance riding, where the minimum age to compete is based on the animal's actual calendar age. The following terminology is used to describe horses of various ages: ; Foal : A horse of either sex less than one year old. A nursing foal is sometimes called a ''suckling'', and a foal that has been weaned is called a ''weanling''. Ensminger, p. 418 Most domesticated foals are weaned at five to seven months of age, although foals can be weaned at four months with no adverse physical effects. ;
Yearling Yearling may refer to: *Yearling (horse), a horse between one and two years old *''The Yearling ''The Yearling'' is a novel by American writer Marjorie Kinnan Rawlings, published in March 1938. It was the main selection of the Book of the Mo ...
: A horse of either sex that is between one and two years old. ; Colt : A male horse under the age of four. A common terminology error is to call any young horse a "colt", when the term actually only refers to young male horses. ; Filly : A female horse under the age of four. ;
Mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than fo ...
: A female horse four years old and older. ; Stallion : A non-castrated male horse four years old and older. The term "horse" is sometimes used colloquially to refer specifically to a stallion. Ensminger, p. 420 ; Gelding : A
castrated Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmac ...
male horse of any age. In horse racing, these definitions may differ: For example, in the British Isles,
Thoroughbred The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are ...
horse racing defines colts and fillies as less than five years old. However, Australian Thoroughbred racing defines colts and fillies as less than four years old.


Size and measurement

The height of horses is measured at the highest point of the
withers The withers is the ridge between the shoulder blades of an animal, typically a quadruped. In many species, it is the tallest point of the body. In horses and dogs, it is the standard place to measure the animal's height. In contrast, cattle a ...
, where the neck meets the
back The human back, also called the dorsum, is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral column runs ...
. Whitaker, p. 77 This point is used because it is a stable point of the anatomy, unlike the head or neck, which move up and down in relation to the body of the horse. In English-speaking countries, the height of horses is often stated in units of hands and inches: one hand is equal to . The height is expressed as the number of full hands, followed by a point, then the number of additional inches, and ending with the abbreviation "h" or "hh" (for "hands high"). Thus, a horse described as "15.2 h" is 15 hands plus 2 inches, for a total of in height. Ensminger, p. 51 The size of horses varies by breed, but also is influenced by
nutrition Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient ...
. Light-riding horses usually range in height from and can weigh from . Larger-riding horses usually start at about and often are as tall as , weighing from . Heavy or
draft horse A draft horse (US), draught horse (UK) or dray horse (from the Old English ''dragan'' meaning "to draw or haul"; compare Dutch ''dragen'' and German ''tragen'' meaning "to carry" and Danish ''drage'' meaning "to draw" or "to fare"), less oft ...
s are usually at least high and can be as tall as high. They can weigh from about . The largest horse in recorded history was probably a
Shire horse The Shire is a British breed of draught horse. It is usually black, bay, or grey. It is a tall breed, and Shires have at various times held world records both for the largest horse and for the tallest horse. The Shire has a great capacity for ...
named
Mammoth A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
, who was born in 1848. He stood high and his peak weight was estimated at . Whitaker, p. 60 The record holder for the smallest horse ever is Thumbelina, a fully mature
miniature horse A miniature horse is a breed or type of horse characterised by its small size. Usually it has been bred to display in miniature the physical characteristics of a full-sized horse, but to be little over in height, or even less. Although such hor ...
affected by dwarfism. She was tall and weighed .


Ponies

Ponies A pony is a type of small horse ('' Equus ferus caballus''). Depending on the context, a pony may be a horse that is under an approximate or exact height at the withers, or a small horse with a specific conformation and temperament. Compared ...
are taxonomically the same animals as horses. The distinction between a horse and pony is commonly drawn on the basis of height, especially for competition purposes. However, height alone is not dispositive; the difference between horses and ponies may also include aspects of
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological pr ...
, including conformation and temperament. The traditional standard for height of a horse or a pony at maturity is . An animal or over is usually considered to be a horse and one less than a pony, but there are many exceptions to the traditional standard. In Australia, ponies are considered to be those under . For competition in the
Western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...
division of the United States Equestrian Federation, the cutoff is . The
International Federation for Equestrian Sports The International Federation for Equestrian Sports (, FEI) is the international governing body of equestrian sports. The FEI headquarters are in Lausanne, Switzerland. An FEI code of conduct protects the welfare of the horses from physical abu ...
, the world governing body for horse sport, uses
metric Metric or metrical may refer to: * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathem ...
measurements and defines a pony as being any horse measuring less than at the withers without shoes, which is just over , and , with shoes. Height is not the sole criterion for distinguishing horses from ponies. Breed registries for horses that typically produce individuals both under and over consider all animals of that breed to be horses regardless of their height. Conversely, some pony breeds may have features in common with horses, and individual animals may occasionally mature at over , but are still considered to be ponies. Ponies often exhibit thicker manes, tails, and overall coat. They also have proportionally shorter legs, wider barrels, heavier bone, shorter and thicker necks, and short heads with broad foreheads. They may have calmer temperaments than horses and also a high level of intelligence that may or may not be used to cooperate with human handlers. Small size, by itself, is not an exclusive determinant. For example, the
Shetland pony The Shetland pony is a Scottish breed of pony originating in the Shetland Isles in the north of Scotland. It may stand up to at the withers. It has a heavy coat and short legs, is strong for its size, and is used for riding, driving, and p ...
which averages , is considered a pony. Conversely, breeds such as the Falabella and other
miniature horse A miniature horse is a breed or type of horse characterised by its small size. Usually it has been bred to display in miniature the physical characteristics of a full-sized horse, but to be little over in height, or even less. Although such hor ...
s, which can be no taller than , are classified by their registries as very small horses, not ponies.


Genetics

Horses have 64
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s. The horse genome was
sequenced In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which suc ...
in 2007. It contains 2.7 billion DNA base pairs, which is larger than the dog genome, but smaller than the
human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. These are usually treated separately as the ...
or the bovine genome. The map is available to researchers.


Colors and markings

Horses exhibit a diverse array of coat colors and distinctive markings, described by a specialized vocabulary. Often, a horse is classified first by its coat color, before breed or sex. Horses of the same color may be distinguished from one another by white markings, which, along with various spotting patterns, are inherited separately from coat color. Many genes that create horse coat colors and patterns have been identified. Current genetic tests can identify at least 13 different
allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
s influencing coat color, and research continues to discover new genes linked to specific traits. The basic coat colors of chestnut and
black Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ...
are determined by the
gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
controlled by the
Melanocortin 1 receptor The melanocortin 1 receptor (MC1R), also known as melanocyte-stimulating hormone receptor (MSHR), melanin-activating peptide receptor, or melanotropin receptor, is a G protein–coupled receptor that binds to a class of pituitary peptide hormones ...
, also known as the "extension gene" or "red factor," as its recessive form is "red" (chestnut) and its dominant form is black. Additional
gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
s control suppression of black color to
point coloration Point coloration refers to animal coat coloration with a pale body and relatively darker extremities, i.e. the face, ears, feet, tail, and (in males) scrotum. It is most recognized as the coloration of Siamese and related breeds of cat, but can ...
that results in a bay, spotting patterns such as pinto or leopard, dilution genes such as palomino or
dun A dun is an ancient or medieval fort. In Ireland and Britain it is mainly a kind of hillfort and also a kind of Atlantic roundhouse. Etymology The term comes from Irish ''dún'' or Scottish Gaelic ''dùn'' (meaning "fort"), and is cognat ...
, as well as greying, and all the other factors that create the many possible coat colors found in horses. Horses that have a white coat color are often mislabeled; a horse that looks "white" is usually a middle-aged or older
gray Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...
. Grays are born a darker shade, get lighter as they age, but usually keep black skin underneath their white hair coat (with the exception of pink skin under white markings). The only horses properly called
white White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White o ...
are born with a predominantly white hair coat and pink skin, a fairly rare occurrence. Different and unrelated genetic factors can produce white coat colors in horses, including several different alleles of dominant white and the sabino-1 gene. However, there are no "
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...
" horses, defined as having both pink skin and red eyes.


Reproduction and development

Gestation lasts approximately 340 days, with an average range 320–370 days, Ensminger, p. 156 and usually results in one foal; twins are rare. Horses are a precocial species, and foals are capable of standing and running within a short time following birth. Foals are usually born in the spring. The
estrous cycle The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestro ...
of a mare occurs roughly every 19–22 days and occurs from early spring into autumn. Most mares enter an ''anestrus'' period during the winter and thus do not cycle in this period. Ensminger, p. 150 Foals are generally
weaned Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk. The process takes place only in mammals, as only mammals produce milk. The infan ...
from their mothers between four and six months of age. Horses, particularly colts, are sometimes physically capable of reproduction at about 18 months, but domesticated horses are rarely allowed to breed before the age of three, especially females. Horses four years old are considered mature, although the skeleton normally continues to develop until the age of six; maturation also depends on the horse's size, breed, sex, and quality of care. Larger horses have larger bones; therefore, not only do the bones take longer to form
bone tissue A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, a ...
, but the
epiphyseal plate The epiphyseal plate (or epiphysial plate, physis, or growth plate) is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the part of a long bone where new bone growth takes place; that is, the whole bone is alive, wit ...
s are larger and take longer to convert from cartilage to bone. These plates convert after the other parts of the bones, and are crucial to development. Depending on maturity, breed, and work expected, horses are usually put under saddle and trained to be ridden between the ages of two and four. Although
Thoroughbred The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are ...
race horses are put on the track as young as the age of two in some countries, horses specifically bred for sports such as dressage are generally not put under saddle until they are three or four years old, because their bones and muscles are not solidly developed. For endurance riding competition, horses are not deemed mature enough to compete until they are a full 60 calendar months (five years) old.


Anatomy


Skeletal system

The horse skeleton averages 205 bones. A significant difference between the horse skeleton and that of a human is the lack of a
collarbone The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the right ...
—the horse's
forelimbs A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. ...
are attached to the spinal column by a powerful set of muscles, tendons, and ligaments that attach the shoulder blade to the torso. The horse's four legs and hooves are also unique structures. Their leg bones are proportioned differently from those of a human. For example, the body part that is called a horse's "knee" is actually made up of the carpal bones that correspond to the human
wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carp ...
. Similarly, the hock contains bones equivalent to those in the human
ankle The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joi ...
and heel. The lower leg bones of a horse correspond to the bones of the human hand or foot, and the
fetlock Fetlock is the common name in horses, large animals, and sometimes dogs for the metacarpophalangeal and metatarsophalangeal joints (MCPJ and MTPJ). Although it somewhat resembles the human ankle in appearance, the joint is homologous to the ba ...
(incorrectly called the "ankle") is actually the proximal sesamoid bones between the
cannon A cannon is a large- caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder ...
bones (a single equivalent to the human
metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...
or
metatarsal bones The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...
) and the
proximal phalanges The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. ...
, located where one finds the "knuckles" of a human. A horse also has no muscles in its legs below the knees and hocks, only skin, hair, bone,
tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...
s, ligaments, cartilage, and the assorted specialized tissues that make up the
hoof The hoof (plural: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits, yet the rum ...
. Ensminger, pp. 21–25


Hooves

The critical importance of the feet and legs is summed up by the traditional adage, "no foot, no horse". Ensminger, p. 367 The horse hoof begins with the
distal phalanges The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. ...
, the equivalent of the human fingertip or tip of the toe, surrounded by cartilage and other specialized, blood-rich soft tissues such as the laminae. The exterior hoof wall and horn of the sole is made of
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...
, the same material as a human
fingernail A nail is a claw-like plate found at the tip of the fingers and toes on most primates. Nails correspond to the claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin, which is a polymer ...
. The result is that a horse, weighing on average , travels on the same bones as would a human on tiptoe. For the protection of the hoof under certain conditions, some horses have horseshoes placed on their feet by a professional
farrier A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary. A farrier combines some blacksmith's skills (fabricating, adapting, and adj ...
. The hoof continually grows, and in most domesticated horses needs to be trimmed (and horseshoes reset, if used) every five to eight weeks, though the hooves of horses in the wild wear down and regrow at a rate suitable for their terrain.


Teeth

Horses are adapted to
grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...
. In an adult horse, there are 12 
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s at the front of the mouth, adapted to biting off the grass or other vegetation. There are 24 teeth adapted for chewing, the premolars and
molars The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
, at the back of the mouth. Stallions and geldings have four additional teeth just behind the incisors, a type of
canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...
called "tushes". Some horses, both male and female, will also develop one to four very small
vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
teeth in front of the molars, known as "wolf" teeth, which are generally removed because they can interfere with the
bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...
. There is an empty interdental space between the incisors and the molars where the bit rests directly on the gums, or "bars" of the horse's mouth when the horse is bridled. An estimate of a horse's age can be made from looking at its teeth. The teeth continue to erupt throughout life and are worn down by grazing. Therefore, the incisors show changes as the horse ages; they develop a distinct wear pattern, changes in tooth shape, and changes in the angle at which the chewing surfaces meet. This allows a very rough estimate of a horse's age, although diet and veterinary care can also affect the rate of tooth wear. Ensminger, pp. 46–50


Digestion

Horses are herbivores with a digestive system adapted to a
forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used ...
diet of grasses and other plant material, consumed steadily throughout the day. Therefore, compared to humans, they have a relatively small stomach but very long intestines to facilitate a steady flow of nutrients. A horse will eat of food per day and, under normal use, drink of
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
. Horses are not
ruminant Ruminants (suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...
s, they have only one stomach, like humans, but unlike humans, they can use
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
, a major component of grass. Horses are hindgut fermenters. Cellulose fermentation by symbiotic bacteria occurs in the
cecum The cecum or caecum is a pouch within the peritoneum that is considered to be the beginning of the large intestine. It is typically located on the right side of the body (the same side of the body as the appendix, to which it is joined). The wo ...
, or "water gut", which food goes through before reaching the
large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before bein ...
. Horses cannot
vomit Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenterit ...
, so digestion problems can quickly cause colic, a leading cause of death. Horses do not have a
gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although ...
; however, they seem to tolerate high amounts of fat in their diet despite lack of a gallbladder.


Senses

The horses' senses are based on their status as prey animals, where they must be aware of their surroundings at all times. Ensminger, pp. 309–310 They have the largest eyes of any land mammal, and are lateral-eyed, meaning that their eyes are positioned on the sides of their heads. This means that horses have a range of vision of more than 350°, with approximately 65° of this being
binocular vision In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an ...
and the remaining 285°
monocular vision In human species Monocular vision vision is known as seeing and using only one eye in the human species. Depth perception in monocular vision is reduced compared to binocular vision, but still is active primarily due to accommodation of the eye a ...
. Horses have excellent day and night vision, but they have two-color, or dichromatic vision; their color vision is somewhat like red-green color blindness in humans, where certain colors, especially red and related colors, appear as a shade of green. Their
sense of smell The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, ...
, while much better than that of humans, is not quite as good as that of a dog. It is believed to play a key role in the social interactions of horses as well as detecting other key scents in the environment. Horses have two olfactory centers. The first system is in the nostrils and nasal cavity, which analyze a wide range of odors. The second, located under the nasal cavity, are the vomeronasal organs, also called Jacobson's organs. These have a separate nerve pathway to the brain and appear to primarily analyze
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s. A horse's hearing is good, and the pinna of each ear can rotate up to 180°, giving the potential for 360° hearing without having to move the head. Noise impacts the behavior of horses and certain kinds of noise may contribute to stress: A 2013 study in the UK indicated that stabled horses were calmest in a quiet setting, or if listening to country or classical music, but displayed signs of nervousness when listening to jazz or rock music. This study also recommended keeping music under a volume of 21 decibels. An Australian study found that stabled racehorses listening to talk radio had a higher rate of gastric ulcers than horses listening to music, and racehorses stabled where a radio was played had a higher overall rate of ulceration than horses stabled where there was no radio playing. Horses have a great sense of balance, due partly to their ability to feel their footing and partly to highly developed
proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...
—the unconscious sense of where the body and limbs are at all times. A horse's
sense of touch In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch ( haptic perception), as well as temperature ( thermoception), body position (proprioception), and pain. It ...
is well-developed. The most sensitive areas are around the eyes, ears, and nose. Horses are able to sense contact as subtle as an insect landing anywhere on the body. Horses have an advanced sense of taste, which allows them to sort through fodder and choose what they would most like to eat, and their prehensile lips can easily sort even small grains. Horses generally will not eat poisonous plants, however, there are exceptions; horses will occasionally eat toxic amounts of poisonous plants even when there is adequate healthy food.


Movement

File:Muybridge horse walking animated.gif, ''Walk'' File:Trot animated.gif, ''Trot'' File:Muybridge_horse_pacing_animated.gif, ''Pace'' File:Canter animated.gif, ''Canter'' File:Muybridge race horse animated.gif, ''Gallop'' , record: All horses move naturally with four basic gaits:
Harris Harris may refer to: Places Canada * Harris, Ontario * Northland Pyrite Mine (also known as Harris Mine) * Harris, Saskatchewan * Rural Municipality of Harris No. 316, Saskatchewan Scotland * Harris, Outer Hebrides (sometimes called the Isle of ...
, p. 32
*the four-beat walk, which averages ; *the two-beat trot or jog at (faster for harness racing horses); *the canter or lope, a three-beat gait that is ; *the
gallop The canter and gallop are variations on the fastest gait that can be performed by a horse or other equine. The canter is a controlled three-beat gait, while the gallop is a faster, four-beat variation of the same gait. It is a natural gait pos ...
, which averages ,
Harris Harris may refer to: Places Canada * Harris, Ontario * Northland Pyrite Mine (also known as Harris Mine) * Harris, Saskatchewan * Rural Municipality of Harris No. 316, Saskatchewan Scotland * Harris, Outer Hebrides (sometimes called the Isle of ...
, pp. 47–49
but the world record for a horse galloping over a short, sprint distance is . Besides these basic gaits, some horses perform a two-beat pace, instead of the trot.
Harris Harris may refer to: Places Canada * Harris, Ontario * Northland Pyrite Mine (also known as Harris Mine) * Harris, Saskatchewan * Rural Municipality of Harris No. 316, Saskatchewan Scotland * Harris, Outer Hebrides (sometimes called the Isle of ...
, p. 50
There also are several four-beat ' ambling' gaits that are approximately the speed of a trot or pace, though smoother to ride. These include the lateral
rack Rack or racks may refer to: Storage and installation * Amp rack, short for amplifier rack, a piece of furniture in which amplifiers are mounted * Bicycle rack, a frame for storing bicycles when not in use * Bustle rack, a type of storage bi ...
, running walk, and
tölt An ambling gait or amble is any of several four-beat intermediate horse gaits, all of which are faster than a walk but usually slower than a canter and always slower than a gallop. Horses that amble are sometimes referred to as " gaited", partic ...
as well as the diagonal fox trot. Ambling gaits are often genetic in some breeds, known collectively as
gaited horse Gaited horses are horse breeds that have selective breeding for natural gaited tendencies, that is, the ability to perform one of the smooth-to-ride, intermediate speed, four-beat horse gaits, collectively referred to as ''ambling gaits''. In mos ...
s. These horses replace the trot with one of the ambling gaits.
Harris Harris may refer to: Places Canada * Harris, Ontario * Northland Pyrite Mine (also known as Harris Mine) * Harris, Saskatchewan * Rural Municipality of Harris No. 316, Saskatchewan Scotland * Harris, Outer Hebrides (sometimes called the Isle of ...
, pp. 50–55


Behavior

Horses are prey animals with a strong
fight-or-flight response The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...
. Their first reaction to a threat is to startle and usually flee, although they will stand their ground and defend themselves when flight is impossible or if their young are threatened. They also tend to be curious; when startled, they will often hesitate an instant to ascertain the cause of their fright, and may not always flee from something that they perceive as non-threatening. Most light horse riding breeds were developed for speed, agility, alertness and endurance; natural qualities that extend from their wild ancestors. However, through selective breeding, some breeds of horses are quite docile, particularly certain draft horses. Horses are
herd animal A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called ''herding''. These animals are known as gregarious animals. The term ''herd'' is ...
s, with a clear hierarchy of rank, led by a dominant individual, usually a mare. They are also social creatures that are able to form companionship attachments to their own species and to other animals, including humans. They communicate in various ways, including vocalizations such as nickering or whinnying, mutual grooming, and
body language Body language is a type of communication in which physical behaviors, as opposed to words, are used to express or convey information. Such behavior includes facial expressions, body posture, gestures, eye movement, touch and the use of space. Th ...
. Many horses will become difficult to manage if they are isolated, but with training, horses can learn to accept a human as a companion, and thus be comfortable away from other horses. Ensminger, pp. 305–309 However, when confined with insufficient companionship, exercise, or stimulation, individuals may develop
stable vices Stable vices are stereotypies of equines, especially horses. They are usually undesirable habits that often develop as a result of being confined in a stable with boredom, hunger, isolation, excess energy, or insufficient exercise. They present ...
, an assortment of bad habits, mostly stereotypies of psychological origin, that include wood chewing, wall kicking, "weaving" (rocking back and forth), and other problems.


Intelligence and learning

Studies have indicated that horses perform a number of cognitive tasks on a daily basis, meeting mental challenges that include food procurement and identification of individuals within a
social system In sociology, a social system is the patterned network of relationships constituting a coherent whole that exist between individuals, groups, and institutions. It is the formal structure of role and status that can form in a small, stable group. A ...
. They also have good spatial discrimination abilities. They are naturally curious and apt to investigate things they have not seen before. Studies have assessed equine intelligence in areas such as problem solving, speed of learning, and
memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...
. Horses excel at simple learning, but also are able to use more advanced cognitive abilities that involve categorization and concept learning. They can learn using
habituation Habituation is a form of non-associative learning in which an innate (non-reinforced) response to a stimulus decreases after repeated or prolonged presentations of that stimulus. Responses that habituate include those that involve the intact org ...
, desensitization,
classical conditioning Classical conditioning (also known as Pavlovian or respondent conditioning) is a behavioral procedure in which a biologically potent stimulus (e.g. food) is paired with a previously neutral stimulus (e.g. a triangle). It also refers to the learni ...
, and operant conditioning, and positive and negative
reinforcement In behavioral psychology, reinforcement is a consequence applied that will strengthen an organism's future behavior whenever that behavior is preceded by a specific antecedent stimulus. This strengthening effect may be measured as a higher fr ...
. One study has indicated that horses can differentiate between "more or less" if the quantity involved is less than four. Domesticated horses may face greater mental challenges than wild horses, because they live in artificial environments that prevent instinctive behavior whilst also learning tasks that are not natural. Horses are animals of habit that respond well to regimentation, and respond best when the same routines and techniques are used consistently. One trainer believes that "intelligent" horses are reflections of intelligent trainers who effectively use response conditioning techniques and positive reinforcement to train in the style that best fits with an individual animal's natural inclinations.


Temperament

Horses are mammals, and as such are
warm-blooded Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The onl ...
, or
endotherm An endotherm (from Greek ἔνδον ''endon'' "within" and θέρμη ''thermē'' "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions inst ...
ic creatures, as opposed to cold-blooded, or
poikilotherm A poikilotherm () is an animal whose internal temperature varies considerably. Poikilotherms have to survive and adapt to environmental stress. One of the most important stressors is temperature change, which can lead to alterations in membrane ...
ic animals. However, these words have developed a separate meaning in the context of equine terminology, used to describe temperament, not
body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
. For example, the "hot-bloods", such as many race horses, exhibit more sensitivity and energy, Belknap, p. 255 while the "cold-bloods", such as most draft breeds, are quieter and calmer. Belknap, p. 112 Sometimes "hot-bloods" are classified as "light horses" or "riding horses", Ensminger, pp. 71–73 with the "cold-bloods" classified as "draft horses" or "work horses". Ensminger, p. 84 "Hot blooded" breeds include "
oriental horse The term oriental horse refers to the ancient breeds of horses developed in the Middle East, such as the Arabian, Akhal-Teke, Barb, and the now-extinct Turkoman horse. They tend to be thin-skinned, long-legged, slim in build and more physically ...
s" such as the
Akhal-Teke The Akhal-Teke ( or ; from Turkmen ''Ahalteke'', ) is a Turkmen horse breed. They have a reputation for speed and endurance, intelligence, and a distinctive metallic sheen. The shiny coat of the breed led to their nickname, "Golden Horses". ...
, Arabian horse,
Barb Barb or the BARBs or ''variation'' may refer to: People * Barb (name), a list of people and fictional characters with the given name or surname * Barb, a term used by fans of Nicki Minaj to refer to themselves * The Barbs, a band Places * Barb, ...
, and now-extinct
Turkoman horse The Turkoman horse, or Turkmene, was an Oriental horse breed from the steppes of Turkoman desert. Its closest modern descendant is thought to be the Akhal-Teke. It influenced many modern horse breeds, including the Thoroughbred horse. Some h ...
, as well as the
Thoroughbred The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are ...
, a breed developed in England from the older oriental breeds. Hot bloods tend to be spirited, bold, and learn quickly. They are bred for agility and speed. They tend to be physically refined—thin-skinned, slim, and long-legged. The original oriental breeds were brought to Europe from the Middle East and North Africa when European breeders wished to infuse these traits into racing and light cavalry horses. Whitaker, p. 43 Whitaker, pp. 194–197 Muscular, heavy
draft horse A draft horse (US), draught horse (UK) or dray horse (from the Old English ''dragan'' meaning "to draw or haul"; compare Dutch ''dragen'' and German ''tragen'' meaning "to carry" and Danish ''drage'' meaning "to draw" or "to fare"), less oft ...
s are known as "cold bloods", as they are bred not only for strength, but also to have the calm, patient temperament needed to pull a plow or a heavy carriage full of people. They are sometimes nicknamed "gentle giants".
Price A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for goods or services. In some situations, the price of production has a different name. If the product is a "good" in the ...
, p. 15
Well-known draft breeds include the
Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct languag ...
and the Clydesdale. Some, like the Percheron, are lighter and livelier, developed to pull carriages or to plow large fields in drier climates. Bongianni, entry 87 Others, such as the Shire, are slower and more powerful, bred to plow fields with heavy, clay-based soils. Ensminger, pp. 124–125 The cold-blooded group also includes some pony breeds. "
Warmblood Warmbloods are a group of middle-weight horse types and breeds primarily originating in Europe and registered with organizations that are characterized by open studbook policy, studbook selection, and the aim of breeding for equestrian spor ...
" breeds, such as the
Trakehner Trakehner is a light warmblood breed of horse, originally developed at the East Prussian state stud farm in the town of Trakehnen from which the breed takes its name. The state stud ( :de:Hauptgestüt Trakehnen) was established in 1731 a ...
or Hanoverian, developed when European carriage and war horses were crossed with Arabians or Thoroughbreds, producing a riding horse with more refinement than a draft horse, but greater size and milder temperament than a lighter breed. Certain
pony A pony is a type of small horse ('' Equus ferus caballus''). Depending on the context, a pony may be a horse that is under an approximate or exact height at the withers, or a small horse with a specific conformation and temperament. Compared ...
breeds with warmblood characteristics have been developed for smaller riders. Warmbloods are considered a "light horse" or "riding horse". Today, the term "Warmblood" refers to a specific subset of
sport horse A sport horse or sporthorse is a type of horse, rather than any particular breed. The term is usually applied to horses bred for the traditional Olympic equestrian sporting events of dressage, eventing, show jumping, and combined driving, but ...
breeds that are used for competition in dressage and show jumping. Strictly speaking, the term " warm blood" refers to any
cross A cross is a geometrical figure consisting of two intersecting lines or bars, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a sa ...
between cold-blooded and hot-blooded breeds. Belknap, p. 523 Examples include breeds such as the
Irish Draught The Irish Draught horse is the national horse breed of Ireland which developed primarily for farm use. Today, they are especially popular for crossing with Thoroughbreds and warmbloods, producing the popular Irish Sport Horses (also called ...
or the Cleveland Bay. The term was once used to refer to breeds of light riding horse other than Thoroughbreds or Arabians, such as the Morgan horse.
Price A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for goods or services. In some situations, the price of production has a different name. If the product is a "good" in the ...
, p. 18


Sleep patterns

Horses are able to sleep both standing up and lying down. In an adaptation from life in the wild, horses are able to enter light sleep by using a " stay apparatus" in their legs, allowing them to doze without collapsing. Horses sleep better when in groups because some animals will sleep while others stand guard to watch for predators. A horse kept alone will not sleep well because its instincts are to keep a constant eye out for danger. Unlike humans, horses do not sleep in a solid, unbroken period of time, but take many short periods of rest. Horses spend four to fifteen hours a day in standing rest, and from a few minutes to several hours lying down. Total sleep time in a 24-hour period may range from several minutes to a couple of hours, mostly in short intervals of about 15 minutes each. Ensminger, p. 310. The average sleep time of a domestic horse is said to be 2.9 hours per day. Horses must lie down to reach REM sleep. They only have to lie down for an hour or two every few days to meet their minimum REM sleep requirements. However, if a horse is never allowed to lie down, after several days it will become sleep-deprived, and in rare cases may suddenly collapse as it involuntarily slips into REM sleep while still standing. This condition differs from
narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affect ...
, although horses may also suffer from that disorder.


Taxonomy and evolution

The horse
adapted In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
to survive in areas of wide-open terrain with sparse vegetation, surviving in an
ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
where other large grazing animals, especially
ruminant Ruminants (suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...
s, could not. Horses and other equids are
odd-toed ungulate Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using four toes on the front legs) o ...
s of the order '' Perissodactyla'', a group of mammals dominant during the
Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...
period. In the past, this order contained 14 
families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...
, but only three—
Equidae Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. All extant species are in the genus '' Equus'', ...
(the horse and related species), Tapiridae (the
tapir Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a pig, with a short, prehensile nose trunk. Tapirs inhabit jungle and forest regions of South and Central America, with one species inh ...
), and Rhinocerotidae (the
rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species ...
es)—have survived to the present day. The earliest known member of the family Equidae was the ''
Hyracotherium ''Hyracotherium'' ( ; "hyrax-like beast") is an extinct genus of very small (about 60 cm in length) perissodactyl ungulates that was found in the London Clay formation. This small, fox-sized animal was once considered to be the earliest know ...
'', which lived between 45 and 55 million years ago, during the
Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
period. It had 4 toes on each front foot, and 3 toes on each back foot. The extra toe on the front feet soon disappeared with the ''
Mesohippus ''Mesohippus'' (Greek: / meaning "middle" and / meaning "horse") is an extinct genus of early horse. It lived 37 to 32 million years ago in the Early Oligocene. Like many fossil horses, ''Mesohippus'' was common in North America. Its shoulder hei ...
'', which lived 32 to 37 million years ago. Over time, the extra side toes shrank in size until they vanished. All that remains of them in modern horses is a set of small
vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
bones on the leg below the knee, known informally as splint bones. Their legs also lengthened as their toes disappeared until they were a hooved animal capable of running at great speed. By about 5 million years ago, the modern ''Equus'' had evolved. Equid teeth also evolved from browsing on soft, tropical plants to adapt to browsing of drier plant material, then to grazing of tougher plains grasses. Thus proto-horses changed from leaf-eating forest-dwellers to grass-eating inhabitants of semi-arid regions worldwide, including the steppes of Eurasia and the Great Plains of North America. By about 15,000 years ago, ''Equus ferus'' was a widespread
holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...
species. Horse bones from this time period, the late
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
, are found in Europe, Eurasia, Beringia, and North America. Yet between 10,000 and 7,600 years ago, the horse became extinct in North America and rare elsewhere. The reasons for this extinction are not fully known, but one theory notes that extinction in North America paralleled human arrival. Another theory points to
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
, noting that approximately 12,500 years ago, the grasses characteristic of a steppe ecosystem gave way to shrub
tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
, which was covered with unpalatable plants.


Wild species surviving into modern times

A truly
wild horse The wild horse (''Equus ferus'') is a species of the genus ''Equus'', which includes as subspecies the modern domesticated horse (''Equus ferus caballus'') as well as the endangered Przewalski's horse (''Equus ferus przewalskii''). The Europea ...
is a species or subspecies with no ancestors that were ever domesticated. Therefore, most "wild" horses today are actually
feral horse 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 ...
s, animals that escaped or were turned loose from domestic herds and the descendants of those animals. Only two wild subspecies, the
tarpan The term tarpan (''Equus ferus ferus'') refers to free-ranging horses of the Russian steppe from the 18th to the 20th century. It is generally unknown whether those horses represented genuine wild horses, feral domestic horses or hybrids. The las ...
and the
Przewalski's horse Przewalski's horse (, , (Пржевальский ), ) (''Equus ferus przewalskii'' or ''Equus przewalskii''), also called the takhi, Mongolian wild horse or Dzungarian horse, is a rare and endangered horse originally native to the steppes of ...
, survived into recorded history and only the latter survives today. The
Przewalski's horse Przewalski's horse (, , (Пржевальский ), ) (''Equus ferus przewalskii'' or ''Equus przewalskii''), also called the takhi, Mongolian wild horse or Dzungarian horse, is a rare and endangered horse originally native to the steppes of ...
(''Equus ferus przewalskii''), named after the Russian explorer Nikolai Przhevalsky, is a rare Asian animal. It is also known as the Mongolian wild horse;
Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...
n people know it as the ''taki'', and the Kyrgyz people call it a ''kirtag''. The subspecies was presumed extinct in the wild between 1969 and 1992, while a small breeding population survived in zoos around the world. In 1992, it was reestablished in the wild by the conservation efforts of numerous zoos. Today, a small wild breeding population exists in Mongolia. Dohner, pp. 298–299 There are additional animals still maintained at zoos throughout the world. The question of whether the Przewalski's horse was ever domesticated was challenged in 2018 when DNA studies of horses found at Botai culture sites revealed captured animals with DNA markers of an ancestor to the Przewalski's horse. The study concluded that the Botai animals appear to have been an independent domestication attempt involving a different wild population from all other domesticated horses. However, the question of whether all Przewalski's horses descend from this domesticated population is unresolved, as only one of seven modern Przewalski’s horses in the study shared this ancestry. The
tarpan The term tarpan (''Equus ferus ferus'') refers to free-ranging horses of the Russian steppe from the 18th to the 20th century. It is generally unknown whether those horses represented genuine wild horses, feral domestic horses or hybrids. The las ...
or European wild horse (''Equus ferus ferus'') was found in Europe and much of Asia. It survived into the historical era, but became extinct in 1909, when the last captive died in a Russian zoo. Dohner, p. 300 Thus, the genetic line was lost. Attempts have been made to recreate the tarpan, which resulted in horses with outward physical similarities, but nonetheless descended from domesticated ancestors and not true wild horses. Periodically, populations of horses in isolated areas are speculated to be
relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...
populations of wild horses, but generally have been proven to be feral or domestic. For example, the Riwoche horse of Tibet was proposed as such, but testing did not reveal genetic differences from domesticated horses. Similarly, the Sorraia of Portugal was proposed as a direct descendant of the
Tarpan The term tarpan (''Equus ferus ferus'') refers to free-ranging horses of the Russian steppe from the 18th to the 20th century. It is generally unknown whether those horses represented genuine wild horses, feral domestic horses or hybrids. The las ...
on the basis of shared characteristics, Edwards, pp. 104–105 but genetic studies have shown that the Sorraia is more closely related to other horse breeds, and that the outward similarity is an unreliable measure of relatedness.


Other modern equids

Besides the horse, there are six other species of
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Equus'' in the Equidae
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
. These are the ass or donkey, ''Equus asinus''; the
mountain zebra The mountain zebra (''Equus zebra'') is a zebra species in the family Equidae, native to southwestern Africa. There are two subspecies, the Cape mountain zebra (''E. z. zebra'') found in South Africa and Hartmann's mountain zebra (''E. z. hartman ...
, ''Equus zebra'';
plains zebra The plains zebra (''Equus quagga'', formerly ''Equus burchellii''), also known as the common zebra, is the most common and geographically widespread species of zebra. Its range is fragmented, but spans much of southern and eastern Africa south o ...
, ''Equus quagga''; Grévy's Zebra, ''Equus grevyi''; the
kiang The kiang (''Equus kiang'') is the largest of the '' Asinus'' subgenus. It is native to the Tibetan Plateau, where it inhabits montane and alpine grasslands. Its current range is restricted to the plains of the Tibetan plateau; Ladakh; and nort ...
, ''Equus kiang''; and the
onager The onager (; ''Equus hemionus'' ), A new species called the kiang (''E. kiang''), a Tibetan relative, was previously considered to be a subspecies of the onager as ''E. hemionus kiang'', but recent molecular studies indicate it to be a distinct ...
, ''Equus hemionus''. Horses can
crossbreed A crossbreed is an organism with purebred parents of two different breeds, varieties, or populations. ''Crossbreeding'', sometimes called "designer crossbreeding", is the process of breeding such an organism, While crossbreeding is used to mai ...
with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a
mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than fo ...
. A related hybrid, a
hinny A hinny is a domestic equine hybrid, the offspring of a male horse (a stallion) and a female donkey (a jenny). It is the reciprocal cross to the more common mule, which is the product of a male donkey (a jack) and a female horse (a mare). The ...
, is a cross between a stallion and a "jenny" (female donkey). Other hybrids include the zorse, a cross between a zebra and a horse. With rare exceptions, most hybrids are sterile and cannot reproduce.


Domestication

Domestication of the horse most likely took place in central Asia prior to 3500 BCE. Two major sources of information are used to determine where and when the horse was first domesticated and how the domesticated horse spread around the world. The first source is based on palaeological and archaeological discoveries; the second source is a comparison of DNA obtained from modern horses to that from bones and teeth of ancient horse remains. The earliest archaeological evidence for the
domestication of the horse A number of hypotheses exist on many of the key issues regarding the domestication of the horse. Although horses appeared in Paleolithic cave art as early as 30,000 BCE, these were wild horses and were probably hunted for meat. How and when ho ...
comes from sites in
Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...
and
Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
, dating to approximately 4000–3500 BCE. By 3000 BCE, the horse was completely domesticated and by 2000 BCE there was a sharp increase in the number of horse bones found in human settlements in northwestern Europe, indicating the spread of domesticated horses throughout the continent. The most recent, but most irrefutable evidence of domestication comes from sites where horse remains were interred with chariots in graves of the
Sintashta Sintashta (russian: Синташта́) is an archaeological site in Chelyabinsk Oblast, Russia. It is the remains of a fortified settlement dating to the Bronze Age, ''c''. 2800–1600 BC, and is the type site of the Sintashta culture. The site h ...
and Petrovka cultures 2100 BCE. A 2021 genetic study suggested that most modern domestic horses descend from the lower Volga-Don region. Ancient horse genomes indicate that these populations influenced almost all local populations as they expanded rapidly throughout Eurasia, beginning about 4,200 years ago. It also shows that certain adaptations were strongly selected due to riding, and that equestrian material culture, including
Sintashta Sintashta (russian: Синташта́) is an archaeological site in Chelyabinsk Oblast, Russia. It is the remains of a fortified settlement dating to the Bronze Age, ''c''. 2800–1600 BC, and is the type site of the Sintashta culture. The site h ...
spoke-wheeled chariots spread with the horse itself. Domestication is also studied by using the genetic material of present-day horses and comparing it with the genetic material present in the bones and teeth of horse remains found in archaeological and palaeological excavations. The variation in the genetic material shows that very few wild stallions contributed to the domestic horse, while many mares were part of early domesticated herds. This is reflected in the difference in genetic variation between the DNA that is passed on along the paternal, or sire line ( Y-chromosome) versus that passed on along the maternal, or dam line ( mitochondrial DNA). There are very low levels of Y-chromosome variability, but a great deal of genetic variation in mitochondrial DNA. There is also regional variation in mitochondrial DNA due to the inclusion of wild mares in domestic herds. Another characteristic of domestication is an increase in coat color variation. In horses, this increased dramatically between 5000 and 3000 BCE. Before the availability of DNA techniques to resolve the questions related to the domestication of the horse, various hypotheses were proposed. One classification was based on body types and conformation, suggesting the presence of four basic prototypes that had adapted to their environment prior to domestication. Another hypothesis held that the four prototypes originated from a single wild species and that all different body types were entirely a result of
selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...
after domestication. However, the lack of a detectable substructure in the horse has resulted in a rejection of both hypotheses.


Feral populations

Feral A feral () animal or plant is one that lives in the wild but is descended from domesticated individuals. As with an introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in some ...
horses are born and live in the wild, but are descended from domesticated animals. Many populations of
feral horse 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 ...
s exist throughout the world. Studies of feral herds have provided useful insights into the behavior of prehistoric horses, as well as greater understanding of the instincts and behaviors that drive horses that live in domesticated conditions. There are also
semi-feral A semi-feral animal lives predominantly in a feral state but has some contact and experience with humans. This may be because it was born in a domesticated state and then reverted to life in wild conditions, or it may be an animal that grew up in ...
horses in many parts of the world, such as
Dartmoor Dartmoor is an upland area in southern Devon, England. The moorland and surrounding land has been protected by National Park status since 1951. Dartmoor National Park covers . The granite which forms the uplands dates from the Carboniferous P ...
and the
New Forest The New Forest is one of the largest remaining tracts of unenclosed pasture land, heathland and forest in Southern England, covering southwest Hampshire and southeast Wiltshire. It was proclaimed a royal forest by William the Conqueror, fea ...
in the UK, where the animals are all privately owned but live for significant amounts of time in "wild" conditions on undeveloped, often public, lands. Owners of such animals often pay a fee for grazing rights.


Breeds

The concept of
purebred Purebreds are " cultivated varieties" of an animal species achieved through the process of selective breeding. When the lineage of a purebred animal is recorded, that animal is said to be "pedigreed". Purebreds breed true-to-type which means the ...
bloodstock and a controlled, written
breed registry A breed registry, also known as a herdbook, studbook or register, in animal husbandry and the hobby of animal fancy, is an official list of animals within a specific breed whose parents are known. Animals are usually registered by their breeder ...
has come to be particularly significant and important in modern times. Sometimes purebred horses are incorrectly or inaccurately called "thoroughbreds".
Thoroughbred The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are ...
is a specific breed of horse, while a "purebred" is a horse (or any other animal) with a defined pedigree recognized by a breed registry. Ensminger, p. 424 Horse breeds are groups of horses with distinctive characteristics that are transmitted consistently to their offspring, such as conformation, color, performance ability, or disposition. These inherited traits result from a combination of natural crosses and artificial selection methods. Horses have been selectively bred since their
domestication Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. ...
. An early example of people who practiced selective horse breeding were the Bedouin, who had a reputation for careful practices, keeping extensive pedigrees of their Arabian horses and placing great value upon pure bloodlines. These pedigrees were originally transmitted via an
oral tradition Oral tradition, or oral lore, is a form of human communication wherein knowledge, art, ideas and cultural material is received, preserved, and transmitted orally from one generation to another. Vansina, Jan: ''Oral Tradition as History'' (1985) ...
. In the 14th century,
Carthusian The Carthusians, also known as the Order of Carthusians ( la, Ordo Cartusiensis), are a Latin enclosed religious order of the Catholic Church. The order was founded by Bruno of Cologne in 1084 and includes both monks and nuns. The order has i ...
monks of southern Spain kept meticulous pedigrees of bloodstock lineages still found today in the Andalusian horse. Breeds developed due to a need for "form to function", the necessity to develop certain characteristics in order to perform a particular type of work. Sponenberg, p. 155 Thus, a powerful but refined breed such as the Andalusian developed as riding horses with an aptitude for dressage. Heavy draft horses were developed out of a need to perform demanding
farm A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used ...
work and pull heavy wagons. Other horse breeds had been developed specifically for light agricultural work, carriage and road work, various sport disciplines, or simply as pets. Sponenberg, p. 162 Some breeds developed through centuries of crossing other breeds, while others descended from a single foundation sire, or other limited or restricted foundation bloodstock. One of the earliest formal registries was
General Stud Book The ''General Stud Book'' is a breed registry for horses in Great Britain and Ireland. More specifically it is used to document the breeding of Thoroughbreds and related foundation bloodstock such as the Arabian horse. Today it is published e ...
for Thoroughbreds, which began in 1791 and traced back to the foundation bloodstock for the breed. There are more than 300 horse breeds in the world today.


Interaction with humans

Worldwide, horses play a role within human cultures and have done so for millennia. Horses are used for leisure activities, sports, and working purposes. The
Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
(FAO) estimates that in 2008, there were almost 59,000,000 horses in the world, with around 33,500,000 in the Americas, 13,800,000 in Asia and 6,300,000 in Europe and smaller portions in Africa and Oceania. There are estimated to be 9,500,000 horses in the United States alone. The American Horse Council estimates that horse-related activities have a direct impact on the economy of the United States of over $39 billion, and when indirect spending is considered, the impact is over $102 billion. In a 2004 "poll" conducted by
Animal Planet Animal Planet (stylized in all lowercase since 2018) is an American multinational pay television channel owned by the Warner Bros. Discovery Networks unit of Warner Bros. Discovery. First established on June 1, 1996, the network is primarily ...
, more than 50,000 viewers from 73 countries voted for the horse as the world's 4th favorite animal. Communication between human and horse is paramount in any equestrian activity; to aid this process horses are usually ridden with a
saddle The saddle is a supportive structure for a rider of an animal, fastened to an animal's back by a girth. The most common type is equestrian. However, specialized saddles have been created for oxen, camels and other animals. It is not k ...
on their backs to assist the rider with balance and positioning, and a bridle or related headgear to assist the rider in maintaining control. Sometimes horses are ridden without a saddle, and occasionally, horses are trained to perform without a bridle or other headgear. Many horses are also driven, which requires a harness, bridle, and some type of
vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...
.


Sport

Historically, equestrians honed their skills through games and races. Equestrian sports provided entertainment for crowds and honed the excellent horsemanship that was needed in battle. Many sports, such as dressage,
eventing Eventing (also known as three day eventing or horse trials) is an equestrian event where a single horse and rider combine and compete against other competitors across the three disciplines of dressage, cross-country, and show jumping. This ...
, and show jumping, have origins in military training, which were focused on control and balance of both horse and rider. Other sports, such as rodeo, developed from practical skills such as those needed on working
ranch A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most ofte ...
es and stations. Sport hunting from horseback evolved from earlier practical hunting techniques. Horse racing of all types evolved from impromptu competitions between riders or drivers. All forms of competition, requiring demanding and specialized skills from both horse and rider, resulted in the systematic development of specialized breeds and equipment for each sport. The popularity of equestrian sports through the centuries has resulted in the preservation of skills that would otherwise have disappeared after horses stopped being used in combat. Horses are trained to be ridden or driven in a variety of sporting competitions. Examples include show jumping, dressage, three-day
eventing Eventing (also known as three day eventing or horse trials) is an equestrian event where a single horse and rider combine and compete against other competitors across the three disciplines of dressage, cross-country, and show jumping. This ...
, competitive driving, endurance riding, gymkhana, rodeos, and fox hunting.
Horse show A horse show is a judged exhibition of horses and ponies. Many different horse breeds and equestrian disciplines hold competitions worldwide, from local to the international levels. Most horse shows run from one to three days, sometimes longer ...
s, which have their origins in medieval European fairs, are held around the world. They host a huge range of classes, covering all of the mounted and harness disciplines, as well as "In-hand" classes where the horses are led, rather than ridden, to be evaluated on their conformation. The method of judging varies with the discipline, but winning usually depends on style and ability of both horse and rider. Sports such as polo do not judge the horse itself, but rather use the horse as a partner for human competitors as a necessary part of the game. Although the horse requires specialized training to participate, the details of its performance are not judged, only the result of the rider's actions—be it getting a ball through a goal or some other task. Edwards, p. 360 Examples of these sports of partnership between human and horse include
jousting Jousting is a martial game or hastilude between two horse riders wielding lances with blunted tips, often as part of a tournament. The primary aim was to replicate a clash of heavy cavalry, with each participant trying to strike the opponen ...
, in which the main goal is for one rider to unseat the other, and
buzkashi Buzkashi ( Pashto/ fa, بزکشی, lit=goat pulling) is a traditional Central Asian sport in which horse-mounted players attempt to place a goat or calf carcass in a goal. It is played primarily in Afghanistan. Similar games are known as kokpar, ...
, a team game played throughout
Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...
, the aim being to capture a goat carcass while on horseback. Horse racing is an equestrian sport and major international industry, watched in almost every nation of the world. There are three types: "flat" racing; steeplechasing, i.e. racing over jumps; and harness racing, where horses trot or pace while pulling a driver in a small, light cart known as a
sulky A sulky is a lightweight cart with two wheels and a seat for the driver, generally pulled by horses or dogs. With horses, a sulky is used for harness racing. The term is also used for an arch-mounted cart on wheels or crawler tracks, used i ...
. A major part of horse racing's economic importance lies in the
gambling Gambling (also known as betting or gaming) is the wagering of something of value ("the stakes") on a random event with the intent of winning something else of value, where instances of strategy are discounted. Gambling thus requires three el ...
associated with it.


Work

There are certain jobs that horses do very well, and no technology has yet developed to fully replace them. For example,
mounted police Mounted police are police who patrol on horseback or camelback. Their day-to-day function is typically picturesque or ceremonial, but they are also employed in crowd control because of their mobile mass and height advantage and increasingly in t ...
horses are still effective for certain types of patrol duties and crowd control. Cattle
ranch A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most ofte ...
es still require riders on horseback to round up cattle that are scattered across remote, rugged terrain. Search and rescue organizations in some countries depend upon
mounted Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, Co ...
teams to locate people, particularly hikers and children, and to provide disaster relief assistance. Horses can also be used in areas where it is necessary to avoid vehicular disruption to delicate soil, such as nature reserves. They may also be the only form of transport allowed in
wilderness area Wilderness or wildlands (usually in the plural), are natural environments on Earth that have not been significantly modified by human activity or any nonurbanized land not under extensive agricultural cultivation. The term has traditionally re ...
s. Horses are quieter than motorized vehicles.
Law enforcement officer A law enforcement officer (LEO), or peace officer in North American English, is a public-sector employee whose duties primarily involve the enforcement of laws. The phrase can include campaign disclosure specialists, local police officers, ...
s such as park rangers or game wardens may use horses for patrols, and horses or mules may also be used for clearing trails or other work in areas of rough terrain where vehicles are less effective. Although machinery has replaced horses in many parts of the world, an estimated 100 million horses, donkeys and mules are still used for agriculture and transportation in less developed areas. This number includes around 27 million
working animal A working animal is an animal, usually domesticated, that is kept by humans and trained to perform tasks instead of being slaughtered to harvest animal products. Some are used for their physical strength (e.g. oxen and draft horses) or for ...
s in Africa alone. Some land management practices such as cultivating and logging can be efficiently performed with horses. In agriculture, less fossil fuel is used and increased environmental conservation occurs over time with the use of draft animals such as horses. Logging with horses can result in reduced damage to soil structure and less damage to trees due to more selective logging.


Warfare

Horses have been used in warfare for most of recorded history. The first archaeological evidence of horses used in warfare dates to between 4000 and 3000 BCE, and the use of horses in warfare was widespread by the end of the
Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
. Whitaker, pp. 30–31 Although mechanization has largely 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 have been used in the 21st century by the Janjaweed militias in the
War in Darfur The War in Darfur, also nicknamed the Land Cruiser War, is a major armed conflict in the Darfur region of Sudan that began in February 2003 when the Sudan Liberation Movement (SLM) and the Justice and Equality Movement (JEM) rebel groups bega ...
.


Entertainment and culture

Modern horses are often used to reenact many of their historical work purposes. Horses are used, complete with equipment that is authentic or a meticulously recreated replica, in various live action
historical reenactment Historical reenactment (or re-enactment) is an educational or entertainment activity in which mainly amateur hobbyists and history enthusiasts dress in historic uniforms or costumes and follow a plan to recreate aspects of a historical event or ...
s of specific periods of history, especially recreations of famous battles. Horses are also used to preserve cultural traditions and for ceremonial purposes. Countries such as the United Kingdom still use horse-drawn carriages to convey royalty and other VIPs to and from certain culturally significant events. Public exhibitions are another example, such as the Budweiser Clydesdales, seen in parades and other public settings, a team of
draft horse A draft horse (US), draught horse (UK) or dray horse (from the Old English ''dragan'' meaning "to draw or haul"; compare Dutch ''dragen'' and German ''tragen'' meaning "to carry" and Danish ''drage'' meaning "to draw" or "to fare"), less oft ...
s that pull a beer wagon similar to that used before the invention of the modern motorized truck. Horses are frequently used in television, films and literature. They are sometimes featured as a major character in films about particular animals, but also used as visual elements that assure the accuracy of historical stories. Both live horses and iconic images of horses are used in
advertising Advertising is the practice and techniques employed to bring attention to a product or service. Advertising aims to put a product or service in the spotlight in hopes of drawing it attention from consumers. It is typically used to promote a ...
to promote a variety of products. The horse frequently appears in coats of arms in heraldry, in a variety of poses and equipment. The
mythologies Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narrati ...
of many cultures, including Greco-Roman,
Hindu Hindus (; ) are people who religiously adhere to Hinduism. Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pages 35–37 Historically, the term has also been used as a geographical, cultural, and later religious identifier for ...
, Islamic, and Norse, include references to both normal horses and those with wings or additional limbs, and multiple myths also call upon the horse to draw the chariots of the Moon and Sun. The horse also appears in the 12-year cycle of animals in the
Chinese zodiac The Chinese zodiac is a traditional classification scheme based on the lunar calendar that assigns an animal and its reputed attributes to each year in a repeating twelve-year cycle. Originating from China, the zodiac and its variations remain ...
related to the Chinese calendar. Horses serve as the inspiration for many modern automobile names and logos, including the
Ford Pinto The Ford Pinto is a subcompact car that was manufactured and marketed by Ford Motor Company in North America from 1971 until 1980 model years. The Pinto was the first subcompact vehicle produced by Ford in North America. The Pinto was marketed ...
,
Ford Bronco The Ford Bronco is a model line of sport utility vehicles manufactured and marketed by Ford. The first SUV model developed by the company, five generations of the Bronco were sold from the 1966 to 1996 model years. A sixth generation of the mo ...
, Ford Mustang,
Hyundai Equus The Hyundai Equus () is a full-size, front-engine, rear-drive, four-door, five passenger luxury sedan manufactured and marketed by Hyundai from 1999 to 2016. The name ''" equus"'' is the Latin word for "horse". In 2009, Hyundai released the sec ...
,
Hyundai Pony The Hyundai Pony (Hangul: 현대 포니), is a small rear wheel drive automobile produced by the South Korean manufacturer Hyundai from 1975 until 1990. The Pony was South Korea's first mass-produced and exported car. The Pony nameplate remained ...
,
Mitsubishi Starion The Mitsubishi Starion is a two-door, turbocharged four-cylinder rear-wheel drive four-seat hatchback sports car manufactured and marketed by Mitsubishi from 1982-1989 — with badge engineered variants marketed in North America as the Conque ...
,
Subaru Brumby A brumby is a free-roaming feral horse in Australia. Although found in many areas around the country, the best-known brumbies are found in the Australian Alps region. Today, most of them are found in the Northern Territory, with the second ...
,
Mitsubishi Colt The Mitsubishi Colt is a nameplate from Mitsubishi Motors that has been applied to a number of automobiles since 1962. It was first introduced with a series of kei and subcompact cars in the 1960s, and then for the export version of the subcompa ...
/
Dodge Colt The Dodge Colt is a subcompact car that was manufactured by Mitsubishi Motors and marketed by Dodge for model years 1971 to 1994 as captive imports. Rebadged variants include the Plymouth Champ and Plymouth Colt, both were marketed by Plymouth. ...
, Volkswagen Polo, Pinzgauer, Steyr-Puch Haflinger, Pegaso, Porsche,
Rolls-Royce Camargue The Rolls-Royce Camargue is a 2-door luxury saloon manufactured and marketed by Rolls-Royce Motors from 1975–1986. Designed by Paolo Martin at Pininfarina, the Camargue was the first post-war production Rolls-Royce not designed in-house (not ...
, Ferrari, Carlsson, Kamaz,
Corre La Licorne Corre La Licorne was a French car maker founded 1901 in Levallois-Perret, at the north-western edge of central Paris, by Jean-Marie Corre. Cars were produced until 1947. The names The first cars were named Corre, but racing successes by a driv ...
, Iran Khodro,
Eicher Eicher may refer to: * Eicher (surname), a surname * Eicher Motors (Eicher Group) * Eicher tractor * Eicher School, a school in the Faridabad district in the state of Haryana, India * 3617 Eicher, a main-belt asteroid See also * Aicher * Aich ...
, and
Baojun Baojun () is a Chinese automobile marque owned by a joint venture of General Motors and SAIC Motor, SAIC-GM-Wuling Automobile. History The Baojun marque was established in 2010 as a cheaper alternative to existing GM brands Chevrolet and Buick ...
.


Therapeutic use

People of all ages with physical and mental disabilities obtain beneficial results from an association with horses. Therapeutic riding is used to mentally and physically stimulate disabled persons and help them improve their lives through improved balance and coordination, increased self-confidence, and a greater feeling of freedom and independence. The benefits of equestrian activity for people with disabilities has also been recognized with the addition of equestrian events to the
Paralympic Games The Paralympic Games or Paralympics, also known as the ''Games of the Paralympiad'', is a periodic series of international multisport events involving athletes with a range of physical disabilities, including impaired muscle power and impaire ...
and recognition of
para-equestrian Para-equestrian is an equestrian sport governed by the International Federation for Equestrian Sports (FEI), and includes two competitive events: One is para-equestrian dressage, which is conducted under the same basic rules as conventional dress ...
events by the
International Federation for Equestrian Sports The International Federation for Equestrian Sports (, FEI) is the international governing body of equestrian sports. The FEI headquarters are in Lausanne, Switzerland. An FEI code of conduct protects the welfare of the horses from physical abu ...
(FEI). Hippotherapy and therapeutic horseback riding are names for different physical, occupational, and speech therapy treatment strategies that use equine movement. In hippotherapy, a therapist uses the horse's movement to improve their patient's cognitive, coordination, balance, and fine motor skills, whereas therapeutic horseback riding uses specific riding skills. Horses also provide psychological benefits to people whether they actually ride or not. "Equine-assisted" or "equine-facilitated" therapy is a form of experiential
psychotherapy Psychotherapy (also psychological therapy, talk therapy, or talking therapy) is the use of psychological methods, particularly when based on regular personal interaction, to help a person change behavior, increase happiness, and overcome pro ...
that uses horses as companion animals to assist people with mental illness, including anxiety disorders, psychotic disorders, mood disorders, behavioral difficulties, and those who are going through major life changes. There are also experimental programs using horses in
prison A prison, also known as a jail, gaol (dated, standard English, Australian, and historically in Canada), penitentiary (American English and Canadian English), detention center (or detention centre outside the US), correction center, correc ...
settings. Exposure to horses appears to improve the behavior of inmates and help reduce
recidivism Recidivism (; from ''recidive'' and ''ism'', from Latin ''recidīvus'' "recurring", from ''re-'' "back" and ''cadō'' "I fall") is the act of a person repeating an undesirable behavior after they have experienced negative consequences of th ...
when they leave.


Products

Horses are raw material for many products made by humans throughout history, including byproducts from the slaughter of horses as well as materials collected from living horses. Products collected from living horses include mare's milk, used by people with large horse herds, such as the
Mongols The Mongols ( mn, Монголчууд, , , ; ; russian: Монголы) are an East Asian ethnic group native to Mongolia, Inner Mongolia in China and the Buryatia Republic of the Russian Federation. The Mongols are the principal membe ...
, who let it ferment to produce
kumis ''Kumis'' (also spelled ''kumiss'' or ''koumiss'' or ''kumys'', see other transliterations and cognate words below under terminology and etymology – otk, airag kk, қымыз, ''qymyz'') mn, айраг, ''ääryg'') is a fermented dairy p ...
. Horse blood was once used as food by the Mongols and other
nomad A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the popu ...
ic tribes, who found it a convenient source of nutrition when traveling. Drinking their own horses' blood allowed the Mongols to ride for extended periods of time without stopping to eat. The drug
Premarin Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of the ...
is a mixture of
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
s extracted from the urine of pregnant mares (pregnant mares' urine), and was previously a widely used drug for
hormone replacement therapy Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. These symptoms can include hot flashes, vaginal ...
. The tail hair of horses can be used for making bows for
string instrument String instruments, stringed instruments, or chordophones are musical instruments that produce sound from vibrating strings when a performer plays or sounds the strings in some manner. Musicians play some string instruments by plucking the ...
s such as the
violin The violin, sometimes known as a ''fiddle'', is a wooden chordophone (string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument (soprano) in the family in regular ...
,
viola The viola ( , also , ) is a string instrument that is bow (music), bowed, plucked, or played with varying techniques. Slightly larger than a violin, it has a lower and deeper sound. Since the 18th century, it has been the middle or alto voice of ...
,
cello The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a Bow (music), bowed (sometimes pizzicato, plucked and occasionally col legno, hit) string instrument of the violin family. Its four strings are usually intonation (music), t ...
, and
double bass The double bass (), also known simply as the bass () (or #Terminology, by other names), is the largest and lowest-pitched Bow (music), bowed (or plucked) string instrument in the modern orchestra, symphony orchestra (excluding unorthodox addit ...
.
Horse meat Horse meat forms a significant part of the culinary traditions of many countries, particularly in Eurasia. The eight countries that consume the most horse meat consume about 4.3 million horses a year. For the majority of humanity's early existe ...
has been used as food for humans and carnivorous animals throughout the ages. Approximately 5 million horses are slaughtered each year for meat worldwide. It is eaten in many parts of the world, though consumption is
taboo A taboo or tabu is a social group's ban, prohibition, or avoidance of something (usually an utterance or behavior) based on the group's sense that it is excessively repulsive, sacred, or allowed only for certain persons.''Encyclopædia Britannica ...
in some cultures, and a subject of political controversy in others. Horsehide leather has been used for boots, gloves,
jackets A jacket is a garment for the upper body, usually extending below the hips. A jacket typically has sleeves, and fastens in the front or slightly on the side. A jacket is generally lighter, tighter-fitting, and less insulating than a coat, which ...
,
baseballs A baseball is a ball used in the sport of the same name. The ball consists of a rubber or cork center wrapped in yarn and covered with white natural horsehide or cowhide, or a synthetic composite leather. A regulation baseball is 9 to 9¼ inche ...
, and baseball gloves. Horse hooves can also be used to produce
animal glue Animal glue is an adhesive that is created by prolonged boiling of animal connective tissue in a process called rendering. In addition to being used as an adhesive it is used for coating and sizing, in decorative composition ornaments, and as a ...
. Horse bones can be used to make implements. Specifically, in Italian cuisine, the horse
tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
is sharpened into a probe called a ''spinto'', which is used to test the readiness of a (pig) ham as it cures. In Asia, the ''saba'' is a horsehide vessel used in the production of
kumis ''Kumis'' (also spelled ''kumiss'' or ''koumiss'' or ''kumys'', see other transliterations and cognate words below under terminology and etymology – otk, airag kk, қымыз, ''qymyz'') mn, айраг, ''ääryg'') is a fermented dairy p ...
.


Care

Horses are
grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...
animals, and their major source of nutrients is good-quality
forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used ...
from
hay Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticat ...
or
pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine ...
. They can consume approximately 2% to 2.5% of their body weight in dry feed each day. Therefore, a adult horse could eat up to of food. Sometimes, concentrated feed such as
grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...
is fed in addition to pasture or hay, especially when the animal is very active. When grain is fed, equine nutritionists recommend that 50% or more of the animal's diet by weight should still be forage. Horses require a plentiful supply of clean water, a minimum of per day. Although horses are adapted to live outside, they require shelter from the wind and
precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
, which can range from a simple shed or shelter to an elaborate
stable A stable is a building in which livestock, especially horses, are kept. It most commonly means a building that is divided into separate stalls for individual animals and livestock. There are many different types of stables in use today; the ...
. Horses require routine
hoof The hoof (plural: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits, yet the rum ...
care from a
farrier A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary. A farrier combines some blacksmith's skills (fabricating, adapting, and adj ...
, as well as
vaccination Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...
s to protect against various diseases, and dental examinations from a
veterinarian A veterinarian (vet), also known as a veterinary surgeon or veterinary physician, is a medical professional who practices veterinary medicine. They manage a wide range of health conditions and injuries in non-human animals. Along with this, vet ...
or a specialized equine dentist. If horses are kept inside in a barn, they require regular daily exercise for their physical health and mental well-being. When turned outside, they require well-maintained, sturdy
fences A fence is a barrier enclosing or bordering a field, yard, etc., usually made of posts and wire or wood, used to prevent entrance, to confine, or to mark a boundary. Fence or fences may also refer to: Entertainment Music * Fences (band), an Amer ...
to be safely contained. Regular grooming is also helpful to help the horse maintain good health of the hair coat and underlying skin. Giffin, p. 90


See also

*
Glossary of equestrian terms This is a basic glossary of equestrian terms that includes both technical terminology and jargon developed over the centuries for horses and other equidae, as well as various horse-related concepts. Where noted, some terms are used only in Americ ...
*
Lists of horse-related topics Lists of horse-related topics are lists related to horses. They include lists of breeds, related species, individual horses (historical and fictional), race horses, horse race results and horse shows Types Breeds *List of horse breeds * Lis ...


References


Sources

* * * * * * * * * * * *


Further reading

*


External links


"Ancient horse bone yields oldest DNA sequence"
* *
Genome of ''Equus caballus''
via
Ensembl Ensembl genome database project is a scientific project at the European Bioinformatics Institute, which provides a centralized resource for geneticists, molecular biologists and other researchers studying the genomes of our own species and other v ...

Genome of ''Equus caballus'' (version EquCab3.0/equCab3)
via
UCSC Genome Browser The UCSC Genome Browser is an online and downloadable genome browser hosted by the University of California, Santa Cruz (UCSC). It is an interactive website offering access to genome sequence data from a variety of vertebrate and invertebrate spec ...

Data of the genome of ''Equus caballus''
via
NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...

Data of the genome assembly of ''Equus caballus'' (versión EquCab3.0/equCab3)
via
NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...
{{taxonbar, from=Q726 Animal-powered transport Mammals described in 1758 Taxa named by Carl Linnaeus Equus (genus) Herbivorous mammals Horse subspecies Livestock National symbols of Burkina Faso National symbols of Lesotho National symbols of Mongolia National symbols of Nigeria National symbols of Turkmenistan Pack animals Symbols of New Jersey