The Missouri Fox Trotter is an American breed of horse with a unique four beat gait. It was bred in the Ozark Mountain foothills, and used by settlers who valued its smoothness.
The breed is best known for its unique gait

Horse gait

Horse gaits are the various ways in which a horse can move, either naturally or as a result of specialized training by humans.-Classification:...

, known as the fox trot

Ambling

The term amble or ambling is used to describe a number of four-beat intermediate gaits of horses. All are faster than a walk but usually slower than a canter or gallop...

,a four-beat diagonal gait in which the horse appears to walk with its front legs and trot with its hind. The gait, however, is not a mixed patter of footfalls, it has a clear pattern of diagonal foot movement where the front foot hits the ground split-second before the opposite rear foot.