Just Stallions

The largest horse in history was a Shire horse named Sampson, later renamed Mammoth, foaled in 1846 in Bedfordshire, England. He stood 21.2½ hands high (i.e. 7 ft 2½ in or 2.20 m ), and his peak weight was estimated at over 3,300 lb (approx 1.5 tonnes). On the other hand, the current record holder for the world’s smallest horse is Thumbelina, a fully mature miniature horse affected by dwarfism. She is 17 inches tall and weighs 60 pounds.

Horse Size Measurement

The English-speaking world measures the height of horses in hands, abbreviated “h” or “hh,” and is measured at the highest point of an animal’s withers. One hand is 4 Imperial inches, or, as defined in British law, 101.6 mm.

Intermediate heights are defined by hands and inches, rounding to the lower measurement in hands, followed by a decimal point and the number of additional inches between 1 and 3. Thus a horse described as 15.2 hh tall, means it is 15 hands, 2 inches, or 62 inches/1.57 m in height.

Horse Size Variations

The size of horses varies by breed, but can also be influenced by nutrition. The general rule for cutoff in height between what is considered a horse and a pony at maturity is 14.2 hands high. (abbreviated “h” or “hh”) (147 cm, 58 inches) as measured at the withers. An animal 14.2h or over is usually considered a horse and one less than 14.2h is a pony.

However, there are exceptions to the general rule. Some smaller horse breeds who typically produce individual horses both under and over 14.2h are considered “horses” regardless of height. Likewise, some pony breeds, such as the Pony of the Americas or the Welsh pony, share some features of horses and individual animals may occasionally mature at over 14.2h, but are still considered ponies.

The difference between a horse and pony is not simply a height difference, but also a difference in phenotype or appearance. There are noticeable differences in conformation and temperament.

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 often have calmer temperaments than horses and also a high level of equine intelligence that may or may not be used to cooperate with human handlers.

Light riding horses such as Arabians, Morgans, or Quarter Horses usually range in height from 14.0 (142 cm) to 16.0 hands (163 cm) and can weigh from 386 kilograms (850 lbs) to about 540 kg (1200 lbs).

Larger riding horses such as Thoroughbreds, American Saddlebreds or Warmbloods usually start at about 15.2 hands (157 cm) and often are as tall as 17 hands (172 cm), weighing from 500 kg (1100 lbs) to 680 kg (1500 lbs).

Heavy or draft horses such as the Clydesdale, Belgian, Percheron, and Shire are usually at least 16.0 (163 cm) to 18.0 hands (183 cm) high and can weigh from about 680 kg (1500 lb) up to about 900 kg (2000 lb).

Ponies cannot be taller than 14.2h, but can be much smaller, down to the Shetland pony at around 10 hands, and the Falabella which can be the size of a medium-sized dog.

However, while many miniature horse breeds are as small or smaller than a shetland pony, because they are bred to have a horse phenotype (appearance), their breeders and registries classify them as very small horses rather than ponies.

Depending on breed, management and environment, the domestic horse today has a life expectancy of 25 to 30 years. It is uncommon, but a few horses live into their 40s, and, occasionally, beyond. The oldest verifiable record was “Old Billy,” a horse that lived in the 19th century to the age of 62. In modern times, Sugar Puff, who had been listed in the Guinness Book of World Records as the world’s oldest then-living pony, died at age 56.

Regardless of a horse’s actual birthdate, for most competition purposes, horses are considered a year older on January 1 of each year in the northern hemisphere and August 1 in the southern hemisphere. The exception is endurance riding, where the minimum age to compete is based on the horse’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. Most domesticated foals are weaned at 4-6 months of age.

Yearling: a horse of either sex that is between one and two years old.

Colt: a male horse under the age of four.

Filly: a female horse under the age of four.

Mare: a female horse four years old and older.

Stallion: a non-castrated male horse four years old and older. Some people, particularly in the UK, refer to a stallion as a “horse.”

Gelding: A castrated male horse of any age, though for convenience sake, many people also refer to a young gelding under the age of four as a “colt.”

In horse racing the definitions of colt, filly, mare, and stallion or horse may differ from those given above. In the United Kingdom, Thoroughbred horse racing defines a colt as a male horse less than five years old and a filly as a female horse less than five years old. In the USA, both Thoroughbred racing and harness racing defines colts and fillies as four years old and younger.

A very rough estimate of a horse’s age can be made from looking at its teeth.

Most “wild” horses today are actually feral horses (see feral horses), animals that had domesticated ancestors but were themselves born and live in the wild, often for generations. However, there are also some truly wild horses whose ancestors were never successfully domesticated.

The “Four Foundations” theory

There is a theory that there were four basic “proto” horses that developed with adaptations to their environment prior to domestication.

There are competing theories, some arguing that the prototypes were separate species, others suggesting that the prototypes were physically different manifestations of the same species. Either way, the most common theories of historical wild species from which other types are thought to have developed suggests the following base prototypes:

The “Warmblood subspecies” or “Forest Horse” (Equus ferus silvaticus, also called the Diluvial Horse), thought to have evolved into Equus ferus germanicus, and which may have contributed to the development of the warmblood horses of northern Europe, as well as older “heavy horses” such as the Ardennais.

Wild species surviving into modern times

The tarpan, Equus ferus ferus, survived into the historical era, but became extinct in 1879. Its genetic line is lost, but its phenotype has been recreated by a “breeding back” process, in which living domesticated horses with primitive features were repeatedly interbred. Thanks to the efforts of the brothers Lutz Heck (director of the Berlin zoo) and Heinz Heck (director of Munich Tierpark Hellabrunn), the resulting Heck horse together with the Konik resembles the tarpan more closely than any other living horse.

Przewalski’s Horse (Equus ferus przewalskii), a rare Asian species, is the only true wild horse alive today. Also known as the Mongolian Wild Horse, Mongolians know it as the taki, while the Kyrgyz people call it a kirtag. Small wild breeding populations of this animal, named after the Russian explorer Przewalski, exist in Mongolia. There are also small populations maintained at zoos throughout the world. After a battle against extinction, the Przewalksi’s Horse is finally flourishing in the wild once again.

Other truly wild equids alive today include the zebra and the onager.

Animals who had domesticated ancestors but were born and live in the wild. These are distinct from wild animals, whose ancestors have never undergone domestication.Several populations of feral horses exist, including those in the western United States and Canada (often called “mustangs”), and in parts of Australia (“brumbies”) and New Zealand (“Kaimanawa horses”).

Isolated feral populations are often named for their geographic location: Namibia has its Namib Desert Horses; the Sorraia lives in Spain and Portugal; Sable Island Horses reside in Nova Scotia, Canada; and New Forest ponies have been part of Hampshire, England for a thousand years.

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

Other modern equids

Other members of the horse family include zebras, donkeys, and onagers.

The Donkey, Burro or Domestic Ass, Equus asinus, like the horse, has many breeds. A mule is a hybrid of a male ass (jack) and a mare, and is usually infertile. A hinny is the less common hybrid of a female ass (jenny) and a stallion.

Breeders have also tried crossing various species of zebra with mares or female asses to produce “zebra mules” (zorses, and zonkeys (also called zedonks or zebroids)). This will probably remain a novelty hybrid as these individuals tend to inherit some of the undomesticated nature of their zebra parent, but they may inherit the zebra’s resistance to nagana pest.

The horse as it is known today adapted by evolution to survive in areas of wide-open terrain with sparse vegetation, surviving in an ecosystem where other large grazing animals, especially ruminants, could not.

Horses and other equids are odd-toed ungulates of the order Perissodactyla, a relatively ancient group of browsing and grazing animals that first arose less than 10 million years after the dinosaurs became extinct. In the past, this order contained twelve families, but only three families— Equidae (the horse and related species), the tapir and the rhinoceros—have survived to the present day.

The earliest equids known as Hyracotherium developed approximately 54 million years ago, during the Eocene period. One of the first true horse species, it had 4 toes on each front foot, and 3 toes on each back foot. the extra toe on the front feet soon disappeared, and by the Pleistocene era, as the horse adapted to a drier, prairie environment, the 2nd and 4th toes disappeared on all feet, and horses became bigger. These side toes first shrunk in size until they have vanished in modern horses. All that remains are a set of small vestigial bones on either side of the cannon (metacarpal or metatarsal) bone, known informally as splint bones, which are a frequent source of splints, a common injury in the modern horse. Their legs also lengthened as their toes disappeared and until they were a hoofed animal capable of running at great speed.

Over millions of years, equid teeth also evolved from browsing on soft, tropical plants to adapt to browsing of drier plant material, and grazing of tougher plains grasses. Thus the 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. For reasons not fully understood, Equus caballus disappeared from North America around 10,000 years ago, at the end of the last Ice Age.

Competing theories exist as to the time and place of initial domestication. The earliest evidence for the domestication of the horse comes from Central Asia and dates to approximately 4,500 BC. Archaeological finds such as the Sintashta chariot burials provided unequivocal evidence that the horse was definitely domesticated by 2000 BC.