Nicknamed "America"s Horse" the Quarter horse is an excellent sprinter. Actually that"s how the Quarter horse got its name-many of the races that this breed won were a quarter mile or less. Working during the week and racing on the weekend this breed found widespread approval in colonial America. As the most popular breed in the fifty states the Quarter horse breed is also the largest breed registered in the world. Not just a racer Quarter horses are also found in arenas of rodeos ranches and shows. Fun Facts: Quarter horses have been clocked at fifty-five miles per hour.