The origins of the Standardbred trace back to Messenger, an English Thoroughbred foaled in 1780, and later exported to the United States. Messenger was the great-grandsire of Hambletonian 10, to whom every Standardbred can trace its heritage. Thus, Standardbreds are a relatively new breed, dating back just under 250 years.
The name “Standardbred” originated because the early trotters (pacers would not come into favour until much later) were required to reach a certain standard for the mile distance in order to be registered as part of the new breed. The mile is still the standard distance covered in nearly every harness race (although varying distances are incorporated into racing in Great Britain).
In many respects, the Standardbred resembles its ancestor the Thoroughbred. It does not stand as tall, averaging 15.2 hands, although it has a longer body. The head is refined, set on a medium-sized neck. The quarters are muscular yet sleek. The clean hind legs are set well back. Standardbreds are bred to either trot or pace. This breed appears in varying colours, although bay, brown and black are predominant. More recently in the southern hemisphere and in the UK, the introduction of skewbald and piebald into the breed has gained popularity.
Standardbred racing is contested on two gaits, the trot and the pace. Trotters move with a diagonal gait; the left front and right rear legs move in unison, as to the right front and left rear. It requires much skill by the trainer to get a trotter to move perfectly at high speeds, even though the trotting gait is a natural one in the animal world.
Pacers, on the other hand, move the legs on one side of their body in tandem: left front and rear, and right front and rear. Pacers, which account for the majority of horses involved in harness racing in Great Britain, are aided in maintaining their gait by plastic loops called hobbles, which assist with their legs moving in synchronization. Due to the sureness of their action, pacers are usually several seconds faster than trotters.