Ponies are often distinguished by their phenotype, a stocky body, dense bone, round shape and well-sprung ribs. They have a short head, large eyes and small ears. In addition to being smaller than a horse, their legs are proportionately shorter. They have strong hooves and grow a heavier hair coat, seen in a thicker mane and tail as well as a particularly heavy winter coat.

Pony breeds have developed all over the world, particularly in cold and harsh climates where hardy, sturdy working animals were needed. They are remarkably strong for their size. Breeds such as the Connemara pony, are recognized for their ability to carry a full-sized adult rider. Pound for pound ponies can pull and carry more weight than a horse.

 Draft-type ponies are able to pull loads significantly greater than their own weight, with larger ponies capable of pulling loads comparable to those pulled by full-sized draft horses, and even very small ponies able to pull as much as 450 percent of their own weight.
Nearly all pony breeds are very hardy, easy keepers that share the ability to thrive on a more limited diet than that of a regular-sized horse, requiring half the hay for their weight as a horse, and often not needing grain at all. However, for the same reason, they are also more vulnerable to laminitis and Cushing's syndrome. They may also have problems with hyperlipemia.

Ponies are generally considered intelligent and friendly, though sometimes they also are described as stubborn or cunning. The differences of opinion often result from an individual pony's degree of proper training. Ponies trained by inexperienced individuals, or only ridden by beginners, can turn out to be spoiled because their riders typically lack the experience base to correct bad habits. Properly trained ponies are appropriate mounts for children who are learning to ride. Larger ponies can be ridden by adults, as ponies are usually strong for their size.

The Connemara pony is a larger pony which occasionally matures over 14.2 hands. For showing purposes, ponies are often grouped into small, medium, and large sizes. Small ponies are 12.2 hands (50 inches (130 cm)) and under, medium ponies are over 12.2 but no taller than 13.2 hands (54 inches (140 cm)), and large ponies are over 13.2 hands but no taller than 14.2 hands. The smallest equines are called miniature horses by many of their breeders and breed organizations, rather than ponies, even though they stand smaller than small ponies, usually no taller than 38 inches (97 cm) at the withers. However, there are also miniature pony breeds.
(From Wikipedia)