Appaloosa horse (ăp´əlōō´sə), breed of light horse developed in the United States by the Nez Percé of Idaho from a horse that originated in Asia and was popular in Europe during the Middle Ages. Lewis and Clark found the breed in the possession of the Nez Percé in 1805. The Appaloosa is characterized by a spotted pattern of markings; it most commonly has solid-colored foreparts and small, dark, round or oval spots over the loin and hips. Famed for its intelligence, speed, stamina, and endurance, it is an outstanding stock and show horse of great popularity. It stands just over 14 hands (56 in./140 cm) and weighs about 1,100 lb (500 kg).