horse

Horses have been domesticated from early in the 2nd millennium BC, probably at first to provide food. Ancient Middle Eastern civilizations used them to draw the chariots of warriors. Later, riding became important and horses were selectively bred to produce larger, stronger animals. Finally they came into use as general draught animals.

Knights jousting before a king, queen, and nobles. The picture is from the French Roman de Petit Jean de Saintre, dating from 1470. Jean de Saintre was a French chevalier, or knight. In order to carry not only a lance-bearing knight in full armour, but also its own body armour, the war-horse was an extremely heavy animal similar to the shire horse of today.

The evolution of the modern horse has taken place over 50 million years, from the fox-sized four-toed Hyracotherium to the largest draught horse at 17 hands (1.73 m/5.6 ft) at the shoulder.

The Welsh cob has existed as a separate breed of pony since before the Middle Ages. Traditionally used to haul carts loaded with timber or for general farm work, their gentle disposition and compact size make them ideally suited to drawing small, private carriages, such as this stick-back gig at the Tregony Horse Show in Cornwall.

Shetland ponies, Cornwall. The Shetland pony is a small but hardy breed, about 10.5 hands, or 70 cm/27 in high. Traditionally, the Shetland Islanders used these strong animals to carry seaweed from the shore up to the fields, where it was spread as a fertilizer. Shetland ponies can still be found at country fairs competing in weight-pulling competitions.

The shire horse is probably a descendant of the English ‘Great Horse’, which was praised by Julius Caesar after the Roman invasion of Britain. Several monarchs since then, recognizing the military usefulness of these large, strong horses, have instituted breeding programmes to maximize their potential. In the 19th century, the shire horse could be seen dragging heavy loads through the badly paved streets of Victorian cities.

Ranch in Patagonia, southern Argentina. Most ranches in Patagonia are in the northern part of the region, near the Colorado and Niger Rivers. Criollo or Creole horses, the national breed of Argentina, are descendants of Spanish horses that ran wild in the Argentinean pampas for several hundred years. The horses, which are now ideally adapted to the South American climate and habitat, are bred for riding and stockwork.

Horses grazing in the ‘Bluegrass State’, Kentucky, USA. Breeding and selling thoroughbred horses is one of the state's largest sources of income. The most intensive area of breeding is around Lexington.

Packhorses and pack-donkeys in a Moroccan street. These animals make excellent transport in mountainous regions where paths are not wide or smooth enough for motorized vehicles.

Hoofed, odd-toed, grazing mammal belonging to the same family as zebras and asses. The many breeds of domestic horse of Euro-Asian origin range in colour from white to grey, brown, and black. The yellow-brown Mongolian wild horse, or Przewalski's horse (Equus przewalskii), named after its Polish ‘discoverer’ in c. 1880, is the only surviving species of wild horse. (Species Equus caballus, family Equidae.)

Przewalski's horse became extinct in the wild because of hunting and competition with domestic animals for food; about 800 survive in captivity. However, in the late 1990s 55 Przewalski's horses were successfully reintroduced to the wild in Mongolia.

Breeds include the Arab, small and agile; the Thoroughbred, derived from the Arab via English mares, used in horse racing for its speed (the present stock is descended from three Arab horses introduced to Britain in the 18th century); the Quarter Horse, used by cowboys for herding; the Lippizaner, a pure white horse, named after its place of origin in Slovenia; and the shire, the largest draught horse in the world at 17 hands (1 hand = 10.2 cm/4 in), descended from the medieval war horses that carried knights in armour. Ponies combine the qualities of various types of horses with a smaller build (under 14.2 hands, or 1.47 m/58 in). The smallest is the hardy Shetland, about 10.5 hands, or 70 cm/27 in high.

The mule, a hardy pack-animal, is the usually sterile offspring of a female horse and a male ass; the hinny is a similarly sterile offspring of a male horse and a female ass, but less useful as a beast of burden.

A horse is sexually mature at two to three years and can live 20 to 30 years in reasonable conditions; a few are known to have lived past 40. The gestation period, from conception to birth of a foal, is 11 months.