See also: Hand (length)

See also: Hand (length)

The height of horses is measured at the highest point of the withers, where the neck meets the back. This point was chosen as it is a stable point of the anatomy, unlike the head or neck, which move up and down.
The English-speaking world measures the height of horses in hands (abbreviated "h" or "hh", for "hands high") and inches. One hand is equal to 101.6 millimetres (4 in). The height is expressed as the number of full hands, followed by a decimal point, then the number of additional inches. Thus, a horse described as "15.2 h" is 15 hands (60 inches (152.4 cm)) plus 2 inches (5.1 cm), for a total of 62 inches (157.5 cm) in height.^[20]

Size varies greatly among horse breeds, as with this full-sized horse and a miniature horse.

The size of horses varies by breed, but also is influenced by nutrition. Light riding horses usually range in height from 14 to 16 hands (56 to 64 inches, 142 to 163 cm) and can weigh from 380 to 550 kilograms (840 to 1,200 lb).^[21] Larger riding horses usually start at about 15.2 hands (62 inches, 157 cm) and often are as tall as 17 hands (68 inches, 173 cm), weighing from 500 to 600 kilograms (1,100 to 1,300 lb).^[22] Heavy or draft horses are usually at least 16 to 18 hands (64 to 72 inches, 163 to 183 cm) high and can weigh from about 700 to 1,000 kilograms (1,500 to 2,200 lb).^[23]
The largest horse in recorded history was probably a Shire horse named Mammoth, who was born in 1848. He stood 21.2½ hands high (86.5 in/220 cm), and his peak weight was estimated at 1,500 kilograms (3,300 lb).^[24] The current record holder for the world's smallest horse is Thumbelina, a fully mature miniature horse affected by dwarfism. She is 17 inches (43 cm) tall and weighs 57 pounds (26 kg).^[25]

Ponies

Main article: Pony

The general rule for height between a horse and a pony at maturity is 14.2 hands (58 inches, 147 cm). An animal 14.2 h or over is usually considered to be a horse and one less than 14.2 h a pony.^[26] However, there are many exceptions to the general rule. In Australia, ponies measure under 14 hands (56 inches, 142 cm).^[27] The International Federation for Equestrian Sports, which uses metric measurements, defines the cutoff between horses and ponies at 148 centimetres (58.27 in) (just over 14.2 h) without shoes and 149 centimetres (58.66 in) (just over 14.2½ h) with shoes.^[28] Some breeds which typically produce individuals both under and over 14.2 h consider all animals of that breed to be horses regardless of their height.^[29] Conversely, some pony breeds may have features in common with horses, and individual animals may occasionally mature at over 14.2 h, but are still considered to be ponies.^[30]
The distinction between a horse and pony is not simply a difference in height, but other aspects of phenotype or appearance, such as 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 may 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.^[26] In fact, small size, by itself, is sometimes not a factor at all. While the Shetland pony stands on average 10 hands (40 inches, 102 cm),^[31] the Falabella and other miniature horses, which can be no taller than 30 inches (76 cm), the size of a medium-sized dog, are classified by their respective registries as very small horses rather than as ponies.^[32]