The modern horse (Equus caballus) has been 60 million years in the making. That is how long it has taken its earliest ancestor, Eohippus, to evolve into the family Equidae. This family includes the zebra, the donkey, and the domestic horse, as well as the less well-known wild asses of the Africa and Asia, and the Przewalski’s wild horse. It is thought that the immediate ancestors of the modern horse were three primitive types of horse. From these, two pony types and two horse types possibly developed; these in turn were the foundation of all the modern types and breeds.
The three primitive horses were the Forest Horse, the Tarpan, and the Przewalski’s Wild Horse. The Forest Horse was from Northern Europe, and was an important ancestor of some modern breeds. It lived in woodland, where galloping speed was not important. It had large hooves to spread its weight on wet ground, and thick hair to protect it. It may have looked like the modern French Poitevin, which lives on the marshes.
The original Tarpan is now extinct, but attempts are being made to recreate it; it evolved in semi-desert conditions in Europe and Asia and had a fine physique, necessary for travelling long distances in search of food. It is believed that the Tarpan’s head shape was similar to that of today’s modern horses.
The Przewalski’s Wild Horse is the only true survivor of the three early types of horse. In Prehistoric times it lived on the steppes of central Asia and Europe. It has more coarse features and a tufted tail – more like an ass than a modern horse. Small numbers have been bred in captivity since 1902, and selected groups are now being used to increase the wild herds.
The four descendants of these three primitive breeds, were the a breed similar to the Exmoor, possibly Britain’s oldest breed – this type lived in the Northwest of Europe and had a thick coat and bushy mane and tail to protect it against the cold and wet; a breed similar to the Highland – this lived in Northern Europe and Asia, and was adapted to be heavily built and resistant to the cold. Type 3 is believed to be similar to the Akhal-Teke, a tough horse that lived mainly in the deserts of central Asia – its slender build and fine coat helped it to lose heat. Type 4 was likely to be similar to an Arab, a fine boned desert horse that lived in Western Asia.
Since then, horses have been bred selectively by humans to create ‘types’ of horses that are particularly suited for particular jobs. For example, a hunter type generally has an ‘intelligent’ head with a straight face, sloping shoulders for galloping cross country, good thickness of bone to be able to carry weight, well angled hocks for jumping, and muscular hindquarters to provide power. Many hunters today are based on a cross between an Irish Draught horse, and a Thoroughbred.
Horses have evolved over millions of years from animals about the size of dogs to the much larger size they are today. The origins of their association with people are unknown, but evidence suggests that they were first domesticated by nomadic Middle Eastern tribesmen around 2000 BC, or even earlier by the Chinese (3500 BC). Unlike dogs and cats, which are predators, horses are prey animals. They feed on grains and grasses and, like all prey animals of open grasslands, they tend to herd together for protection and take flight in response to danger or any unsettling circumstance. There are over 300 different breeds of horses worldwide today, and there are countless coat colours and markings. Horses are measured from the withers, the highest part of the back, lying at the base of the neck above the shoulders, and can range from around 1m to 1m 80cm depending on the breed. However the world’s smallest living horse, a dwarf miniature horse, measures only 45cm, and equally the world’s largest living horse, a Belgian draft horse measures 2m 10cm! With varied height comes varied weight, and generally horses can weigh anything from 150kg, to over 900kg, depending on build, breed height, muscle etc. There is little difference between the height and weight of each gender.
The modern horse’s skeleton is made up of around 205 bones. The horse has 7 neck vertebrae, 29 spinal vertebrae, 15-22 tail vertebrae, and 18 pairs of ribs. Most of the horse’s weight is slung between the ‘pillars’ of the front and back legs. The horse’s spine has to be very rigid to support its weight, and is not fully mature until five years of age. The heavy head acts on the end of the neck acts as a balance to the body during movement.
The normal rates in a healthy horse at rest are a body temperature of 38.40C, a pulse rate of roughly 40 beats per minute and a respiratory rate of around 12 breaths per minute.
The equine leg is designed for rapid movement over a variety of surfaces. The upper part of the leg is heavily muscled, while the lower part acts as a springboard to enhance the stride. The leg is supported by a suspensory apparatus of tendons and ligaments. The tendons, which can be felt along the back of the lower leg, run the length of the limb, while the many joints are held together and protected by ligaments and joint capsules. Horses also have a unique anatomical feature called the stay apparatus, which allows them to “rest” a rear leg while standing on the other 3 for prolonged periods. This is why horses can sleep standing up. Horses walk and run on their hooves. The cannon and splint bones are in the lower leg, while the pastern bones are between the fetlock and the hoof. The long, lean, flexible equine leg is excellent for its purpose.
The hoof consists of a wall of keratin (a protein) that grows down from a band called the coronet at the top of the hoof. This process is similar to the way fingernails grow out from the cuticle. The sole of the equine foot is concave, with a resilient wedge of tissue called the frog that juts forward from the heel. Inside the hoof is the coffin bone (which is shaped like the hoof) and additional resilient tissue. The sole and the frog protect the underside of the foot, while the resilient tissues cushion each step like a spring.
A horse has four main gaits, walk, trot, canter and gallop. They are as follows:
At the walk, the horse has three feet on the ground and only one foot in the air at any time. It places each foot on the ground in turn; first a hind leg, followed by a foreleg on the same side, then the other hind leg and finally the remaining foreleg.
At the trot, opposite forefeet and hind feet hit the ground together in turn to give a two-beat gait. The fact that only one forefoot or hind foot is bearing weight at any one time makes trot the easiest gait to detect lameness.
At the canter, two diagonal feet hit the ground together while the other two hit the ground separately. This makes a three beat gait. One forefoot is followed by the opposite hind foot, then the other two feet together. There is a time when no feet hit the ground.
This follows the same pattern as the canter, but the paired limbs don not hit the ground together. The hind limb lands slightly before the paired forelimb, making a four beat gait. In the gallop and the canter, a horse can change the leading foreleg.
The main functions of the hair coat are to protect the skin and to help regulate temperature. The hair coat changes with the seasons, with hair being longer and coarser in the winter than in the summer. Like dogs and cats, horses are able to fluff up their hair (using small muscles attached in the hair follicles) to increase the amount of trapped air for insulation. Additional oil (sebum) is also produced by the skin during winter, adding insulation. Proper nutrition, daily cleaning and brushing with a curry comb, and occasional baths are generally all that is needed to keep the skin and hair clean and healthy. A horse’s coat can come in a wide range of colours, as the coats of early horses were probably particular colours to provide camouflage, but the majority of colours we see today have been developed by humans through selective breeding. Coat colour is determined by the dominant and recessive chromosomes inherited from parents. The order of dominance of the main block colours to each other is grey, bay, brown then black, with chestnut being recessive. There are block (or plain) colours, roans, coloureds, appaloosas, and many more.
The body colouring is brown with a block mane and tail. Bay horses often have black points; markings on the muzzle, tips of the ears, and lower legs. Even within this ‘plain’ coat colour there are different coat variants, including bright, dark, light and mahogany.
The body is reddish brown with not black points. The mane and tail are either lighter (flaxen) or darker shade of the body colour. There are often white markings on the legs and/or face. Again, there are different coat variants, including bright, red, and liver. The different coat variants are determined by the reddish-gold shades within the coat.
The coat is a definite black colour with no trace of brown hair. The mane and tail are always black, but they may have white markings on the legs or face.
The body is a mixture of black and brown hair with a dark brown mane and tail.
The skin pigment is dark and the coat contains mostly white hairs with a small amount of black hairs mixed in. Grey horses are generally born dark, and lighten with age. Different variants of grey include; light - which looks completely white, flea-bitten – where the coat contains dark, freckle-like specks, iron – a very dark grey, and dappled – which has dark rings on a grey coat.
White hairs are mixed evenly into the main coat colouring, and the mane and tail may also contain white hairs. There are different shades of roan, such as strawberry and red roan, in which white hairs are mixed into either a chestnut or a bay coat; blue roan, which is a black body mixed with whiteish grey hairs giving the coat a blue-ish tinge; grey roan, and bay roan.
The coat is golden, and the mane and tail is lighter. The horses may have white markings on the legs to below the knee, and on the face.
The coat is covered in large, irregular patches of white, and any other colour than black. The skin pigment is pale under the white patches, and dark under the dark patches. The tail almost always contains both coat colours, and the mane continues the pattern seen on the neck.
Similar to skewbald, except the coat always has patches of black and white.
The skin pigment is dark, but the coat is beige or biscuit coloured, usually with black points like a bay horse, and with a dark dorsal stripe along the spine. Some have dark with stripes and zebra stripes on the legs. The man and tail are black, or black with white for some breeds. Dun ranges in shades, and a creamy yellow coat is called yellow-dun.
The skin pigment is pale and the coat colouring is a pale cream colour, with the mane and tail a pale cream also. Sometimes it is possible to distinguish white leg and face markings.
There are five recognised patterns for the appaloosa, so not all spotted horses are actually appaloosas. The coat configurations are: blanket, which has white hair over the hips and may or may not have dark spots; marble, when the coat is red, or blue roan with dark colouring at the edges of the body and a white frost pattern in the middle; leopard, a white coat colouring with dark spots; snowflake, with dominant spotting over the hips; and frost, which is white speckling on a dark coat. All Appaloosas have mottle skin on the nose and gentalia and tend to have white sclera around the eyes. Often hooves have vertical dark stripes on them.
Additional markings, usually in white, can be observed on horses in the majority of breeds and colours. These markings tend to be on the legs or on the face.
Leg markings are usually described as socks, or stockings, depending on where on the legs they reach. White extending up to the fetlock joint is called a sock, extending up to the cannon bone is called a stocking.
There are many different facial markings, including, but not limited to the star, stripe, snip, blaze and face. The star is any marking between or above the eyes, and the stripe is any vertical white marking down the face. A wide vertical marking down the face is often called a blaze. A snip is any white marking on the horse’s lower face or muzzle. A white face means any facial marking that extends widthways past the horse’s eyes.
The colour of horses’ hooves also differs. The hoof may be dark and pigmented, creamy and pale, or a mix of both. If both colours are present, the boundary is always a vertical one, producing a vertical striping effect.
Horses’ eyes are generally either brown, or blue. The majority of horses have a brown pigmented iris in both eyes. Irises with no colour or a tinge of blue are called
One of the horse’s natural instincts is to eat and drink, much like any creature. To obtain nourishment from its natural food of grass, a horse needs to spend most of the say grazing. In the wild, it will eat the food around it then move to a new area to find more.
When a zebra runs from a lion, it is using its natural instinct for survival. The horse has the same “fight and flight” response to danger, even when domesticated.
Another instinct of the horse is to reproduce; even when a domestic mare or stallion is not being used for breeding its reproduction system is still active. Mares come into season for five days every three weeks in the summer, ready to breed.
Natural behaviours include by playing, rolling, and even sunbathing; all these are for relaxation. Young horses learn their communication skills from play. Like all youngsters, they also have mock fights. They also seek a lot of physical contact. Horses will roll for pleasure; it involves almost all the muscles in the body and so it’s the equivalent of having a good stretch. They also roll to rub their back, or roll in dust for a cleansing bath. Horses will choose to lie down in sunny weather if there are other herd members still standing, and will doze as though sunbathing; however they aren’t asleep and are still aware of possible danger.
Social - The Herd
A herd of wild horses will include animals of both genders and all ages. The desire to be with other horses is so strong that a horse would prefer to be in a group with other horses they do not know than be on their own. It is normal for stallions to collect and mate with mares and fight other male horses. Fighting within a herd is usually triggered by a need to preserve a particular position within the hierarchy, or a desire to challenge another horse and perhaps gain a higher position. As a result, these fights tend to be more ritual posturing than causing serious physical damage.
The herd is an extended family, and many members contribute to the care and education of foals. Young horses naturally gather together and the nearest adult will usually act as ‘nanny’, even if it is a stallion. This is not as altruistic as it seems – all the adults want to establish dominance over the young ones, not just the dams.
Reproduction and development
A normal equine pregnancy will last an average of 340 days, but may be as short as 310 days, or as long as 365 days, and the majority of foals are born in the Spring.
The first few hours of a foal’s life are very important; the first skill it must learn, especially important as an animal of prey, is to stand on its own four feet. Most foals are able to stand within their first hour of life, and can be gallop alongside its mother within 24 hours of its birth. The next skill to be learnt is how to suckle. Most foals pick this up within the first two hours, and must have good feeds within the first 24 hours to obtain its protection against future infections. The mare’s first milk, the colostrum, is highly concentrated with all the nutrients the foal needs as well as antibodies to promote the immune system. Colostrum protects foals against bacterial and viral infections, such as septicemia and pneumonia. Efficient protection against infections and proper growth of the foal depend on the absorption, quality and quantity of colostrums intake. The milk is produced during the last two to three weeks of the mare’s pregnancy and production gradually decreases as the foal suckles. The foal is born with just their temporary premolar teeth, but by ten days old they should have their central two incisors, and start to pick solid foods at six weeks old. Generally they will start trying to graze from about six weeks, and will learn the skill by copying their mother.
Foals have very long legs in proportion to their size and often when trying to graze they will have to bend their knees to reach the ground.
Yearlings are very often characteristically ungainly, and are still leggy in comparison to their size. They tend to grow in spurts, and often their appearance and shape changes dramatically very quickly. During growth spurts, the croup is often higher than the withers, but this generally evens itself out as the young horse grows.
Some of the ‘epiphyses’ growth plates on the long bones of the legs do not stop growing until the horse is between two and three years old, and the horse should be fully grown by five years of age.
A horse continues to develop mentally throughout its life.
A horse reaches puberty at around two years old; a stallion will remain fertile until the end of his life, and mares will remain fertile up until their late teens.
The history of the horse as an instrument of work and leisure goes back to the very beginnings of man’s relationship with animals, and continues, indeed flourishes, to this day.
The Warhorse was of great importance to the early warriors; one shining example was Alexander the Great’s charger, Bucephalus. When Bucephalus died in 326BC, Alexander to Great buried him and named the city near his grace, Bucephala. The earliest battles were probably carried out from the horse-drawn chariots, and then from approximately 500BC, the warring Greeks employed the services of mounted archers. It is likely that during the Roman Empire horses were used to transport soldiers to and from the scenes of battle, but that once there, the fighting took place largely on foot.
Until the 15th century, horses in Britain were small by today’s standards, being more pony than horse size. Henry VIII made a conscious effort to increase the height of the British horse by decreeing that stallions kept on common land had to be over 1.5m and also that landowners had to own at least two mares that were over 1.3m. Horses on the continent were larger, and Britain started to import these to increase the size and stockiness of the British horse. It was an obvious advantage to have a larger horse for use in warfare.
During the Middle Ages, the light draft horse was the favoured mount of knights. One knight’s armour could weigh up to 190kg, so working horses needed to be large and strong. They were however, still considerably smaller than the draught horse of today. In 1651, lighter Arabian horses began to replace draught horses in the British Cavalry, favoured for their speed and agility.
The Victory at the British Battle of Waterloo against Napoleon in 1815, was in part due to the superior and heavier British horse compared to the light weight French horses.
The early years of the First World War were the last time that horses played a major part in British warfare. There were approximately one million horses and mules employed by the British Army, but from then on, were replaced with mechanisation. Today in Britain, the Household Cavalry can be seen on guard duty outside Buckingham Palace.
The Horse as means of transport has been invaluable since it was first domesticated. There is great debate as to when exactly man began to first ride and use the horse in harness. Evidence of wear on the teeth caused by a bit can be dated to around 2000BC from remains at Malyan in Iran, and from remains at Dereivka in Ukraine to approximately 4200BC. Although horses were controlled using bridles and bits, the development of the saddle and stirrups did not appear until much later.
Very early vehicles were made entirely from wood, including the wheels and would have a central pole to which two animals were harnessed, one either side. The earliest types of harness were probably developed for oxen, and were in the form of a yoke which was attached to the ox’s horns.. but when a yoke was places over a horse’s withers, it would restrict movement, and so the ‘modern’ horse collar was invented during the early medieval times.
Industry and commerce
The horse has played a powerful part in industry over the years, and the development of the horse as a draft animal must have contributed greatly to early trading. For the first time, people were able to travel and carry their wares with them in order to trade with neighbouring communities. The Great Khan, grandson of Ghengis Khan, had the foresight to establish a messenger service all over his empire, which relied on delivering message on horseback. This was in a way a prelude to the modern postal service. Horse drawn mail coaches were developed as the roads improved through the 19th century. Deliveries of all kind were made possible by the horse drawn vehicles. Horses were still employed by railroad companies long after the advent of the railways for use in the freight yards and for moving rolling stock.
It was a common sight to see horses pulling barges up the canals, being able to move loads of 60 to 70 tonnes at a time in this way.
Mining has had a long relationship with the horse, with thousands of ‘pit ponies’ used in the mines, many of whom spent their whole lives underground. Miners also used horses to turn the windlass of the hoist at the pitheads and to pull the coal wagons.
Although horses have been used in agriculture for thousands of years, their role was really developed during the 18th and 19th centuries, as they were used to replace the slower oxen. Different breeds were developed depending on the type of land and the country. While it was often the Shire and the Clydesdale and Percheron that are associated with agricultural work, hilly areas such as the highlands of Scotland, the native ponies were much more suitable to cultivating the land. The horse continues to be used widely in parts of North America, South America and Australia to herd cattle and sheep, and some farmers keep a team of horses that can work in areas where a tractor would become stuck.
The first mounted police division was the London Bow Street Horse Patrol, which was formed in 1758, and horses continue to be used to great effect by mounted police for crowd control purposes as well as for patrolling streets and parks. The horses have to undergo intense training to prepare them for the frightening noise and atmosphere of the crowd work, as well as having to learn to cope with the heavy traffic of inner-city life.
In countries such as India, which employs huge numbers of mounted police, the police horse is frequently used for patrolling rural and inaccessible areas of the countryside.
The majority of the horse population today is kept on a leisure basis.Owners ride for fun, or may compete at events such as dressage, riding or cross country. Horses are raced, both on the flat and over hurdles, and there are a number of games to be played on horseback, including polo, polocrosse and horseball. Then there are sports like vaulting, in which the horse is used on a lungeline, to travel in circles whilst gymnasts perform on the horse’s back.
The history of the horse in art spans many thousands of years, and goes back to before the horse was domesticated. The discoveries of cave paintings from 20,000BC at Lascaux and Avignon in France have provided us with an insight into the early appearance of the primitive horse, and also suggests that the horse maybe have been considered as spiritual or God-like creatures.
Around 12,000 years ago, the human population of Western Europe was steadily growing, and wild horses would have provided a good source of food and hides. Some of the best archaeological findings which indicate the start of man’s domestication of horses were excavated in the 1960s and 1980s from a late Neolithic settlement known as Dereivka, in Ukraine; the bones of 52 horses were found, including the skull and limb bones of a stallion. Studies of the skull have shown abnormal war on the premolar teeth, which would indicate the use of primitive bits, used to control the horse. This evidence suggest that horses were first ridden around 6,000 years ago, approximately 500 years before the invention of the wheel.
Early depictions of man on horses shows him adopting a seat far back on the horses loins, which is believed to be how early donkeys were ridden, and is hence known as ‘donkey position’ There are depictions dating back to the eighth century BC, of Assyrians riding in the ‘modern’ position behind the withers, which is likely to be when this seat was developed. There are elaborate carvings from Assyrian places showing the nobility hunting from horseback; they had not yet developed the saddle and had devised a unique bridle where the reins were attached to the riders’ feet keeping their hands free for their weapons.
Greeks and Romans developed chariot racing and other equine pursuits, and these were included within the ancient Olympic Games.
The Pazyryk Tombs were a group of tombs discovered in 1929 and 1949 in Siberia. The tombs date from the late fourth century BC and contained the remains of around 14 horses each. By a remarkable twist of nature, water had seeped into the tombs and frozen the remains, preserving the bridles, saddle cloths, harness and decorative head dresses to a very high degree. The remains were detailed enough to show how the horses had their manes trimmed and their tails plaited, their ears notched and how they had been dressed.
Horses have the same 5 senses as people do but to very different degrees. Some senses are less developed than in people, while others are more powerful.
The primary sensory input in horses is sight. The importance of vision is reflected in the size of the equine eye, which is the largest of any land mammal, and by the fact that the visual cortex of the equine brain handles one-third of all sensory input.
Horses' eyes are set on the side of the head, rather than facing front as in people, dogs, and cats. This gives them extraordinary peripheral vision, which is useful for animals that must constantly watch for predators. Horses can generally see over a 340° arc without moving their heads, with only small blind spots directly behind and in front of them. These blind spots are caused by the body of the horse (behind) and the large forehead and muzzle (in front) obstructing the horse's vision. Horses step slightly to the side to see things behind them, and back up and lower their head to see directly in front.
Horses see a panoramic view as a form of monocular vision, which means that each eye is viewing images independently. These images are transferred to a band of retinal cells called cones within a “retinal streak.” A second group of cones provides binocular vision in an arc of 55 to 65° in front of the horse. The relatively large number of cones enables horses to see distinct images better than dogs do but not quite as well as people can. These cones also mean that horses have some color vision. Horses also have a large number of rods, which are the specific type of cells in the retina responsible for night vision, as well as the reflective tapetum lucidum, which is also found in both dogs and cats. For this reason, horses see considerably better in the dark than people, and even cats. Horses also share the protective third eyelid that is found in both dogs and cats.
Because horses rely on monocular vision, they have poor depth perception. They can misjudge the depth of a small puddle or the distance to a fence. Horses compensate for this by comparing the size of an object to their memory of what they have seen in the past. For example, if a person or fence appears smaller, then it must be farther away. A horse will lower its head to judge closer distances and raise it to judge objects farther away.
In general, horse vision is a little blurrier and a little less colorful than human vision. However, horses see movement very well throughout the 340° arc of their peripheral vision. This is why horses may “spook” when confronted with even minor changes around them—another useful survival skill for herd animals.
Horses have large ears that are good at magnifying sound and noting its direction. Each ear can swivel independently up to 180°, allowing horses to locate multiple sounds at the same time. The ears also provide clues to a horse's emotional state. For example, a horse with ears that are laid back may be indicating aggression, pain, or fear, such as in response to a loud or unfamiliar noise.
In general, horses hear slightly better than people do and are able to hear sounds at both higher and lower frequencies. Horses are good at hearing the high-pitched squeaks or crackles associated with the stealthy approach of a predator.
Smell and Taste
In addition to providing information about the world in general, the sense of smell is the primary way that horses recognize each other as well as people. For example, horses exchange breath on meeting, and stallions assess the sexual status of a mare through scent. The equine nose has a large internal surface area that contains many chemical receptors within the mucous membrane. The surface area devoted to scent detection is many hundred times greater than in people, again highlighting the importance of the equine sense of smell.
Horses enjoy their food through the sense of taste, which also helps them avoid unpalatable or poisonous food or water. Taste buds are located on the tongue, the soft palate, and the back of the throat. It is not known whether horses have the 4 -basic types of taste (sweet, sour, bitter, and salty). However, it is known that they can at least distinguish salty and sweet. In fact, like people, horses are known to have a sweet tooth, appreciating such things as apples, carrots, and honey. Horses are also known to tolerate substances (including medications) that people generally find very bitter.
The horse has an acute sense of touch over its whole body, enabling it to detect the presence of a single fly and whish it away with its tail with unerring accuracy. A horse also has whiskers, long hairs around its eyes, which are important for sensing nearby objects.
The horse is a herd animal and needs to be able to communicate with other members of the herd in order to convey emotions such as fear, and to establish a hierarchy of dominance without resorting to violence.
Contentment can be shown by high head and tail carriage, and more extravagant movements. A horse could show impatience by nudging with its muzzle or by stamping its feet. Annoyance and anger can be signified by horses flattening their ears backwards, baring teeth and biting. A sign of aggression would be for a horse to show the whites of its eyes, and to approach in order to kick or to bit. This is unusual, as horses tend to be flight, rather than fight, creatures. A frightened horse might also show the whites of its eyes, but is more likely to back of or run away.
In contrast to signals of aggression within a herd, there are also signs of friendship. Mares and foals nudge and nuzzle each other during nursing or for comfort, and mutual grooming, when two horses nibble at each other, is often seen.
Horses also have a variety of methods of vocal communication. Vocal noises include a squeal or scream which usually denotes a threat by a stallion or mare. Nickers are low-pitched and quiet. A stallion will nicker when courting a mare; a mare and foal nicker to each other; and domestic horses nicker for food. Neighs or whinnies are the most familiar: high pitched, drawn out sounds that can carry over distances. Horses whinny to let others know where they are and to try to locate a herd mate. They also respond to each other’s whinnies even when out of sight.
Blowing is a strong, rapid expulsion of air resulting in a high pitched whooshing” sound, which usually is a sign of alarm used to warn others. Snorting is a more passive, shorter lower pitched version of blowing and is usually just a result of objects entering the nasal passage, but can also be used to signal excitement.
~ The DK Complete Horse Care Manual, by Colin Vogel, B.Vet.Med., MRCVS, 2003
~ The Parragon Encyclopedia of Horses & Ponies, by Tamsin Pickeral, 2005
~ Echo’s Brain XD