Horses can be classified by size and build as draft horses, light horses, ponies, and miniature horses.
Draft Horses belong to breeds whose members average 14.2 to 17.2 hands in height and weigh 1,400 pounds (635 kg) or more.
Light horses belong to breeds whose members average 14.2 to 17 hands in height and weigh an average of 900 to 1,400 pounds (400 to 635 kg).
Ponies belong to breeds whose members average less than 14.2 hands in height and weigh, on the average, 500 to 900 pounds (225 to 400 kg). (Some individual horses belonging to full-size breeds may be this small, but they are not classified as ponies.)
Ponies often exhibit thicker manes, tails, and overall coat than horses. 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.
Light horses and ponies are sometimes further classified by use, into riding horses, race horses, and driving horses.
Miniature Horses cannot be taller than 34 inches when measured at the last hairs of the mane. They are the product of nearly 400 years of selective breeding, initially in Europe.
Miniatures were first imported to the United States in the early 1900's as work horses to take advantage of their great strength in pulling ore carts in coal mines.
As their utility decreased with the advent of industrialization, a few far sighted individuals started to breed Miniatures as unique pets.
From these beginnings came the forebears to the American Miniature Horse Association and the American Miniature Horse Registry which serve as registries for the American Miniature Horse.
Also see Types of Horses
which includes horses with similar characteristics or suitability for a particular purpose that are commonly grouped together, but are not a formal horse breed by themselves. Horse "types" also include slang terms used for similar horses that developed in a specific geographical area.