Breed of light horse developed in the U.S., primarily for harness racing.
The foundation sire was an English Thoroughbred imported in 1788; his progeny were bred with other breeds, especially the Morgan , to produce speedy trotters and pacers. The Standardbred's height is 15–16 hands (60–64 in. [152–163 cm]); its weight is 900–1,000 lb (410–450 kg). Colour varies, but the most common is bay. "Standard" refers to a requirement imposed in 1871 that, to be registered, a horse must meet certain standards of speed (e.g., trotting a mile in 2.5 minutes).