Bit (horse)

The mullen extends across the horse's mouth and rests on the bars, the region between the incisors and molars where there are no teeth.

The bit applies pressure to the horse's mouth, and reinforces the other control signals from the rider's legs and weight distribution.

Types of headgear for horses that exert control with a noseband rather than a bit are usually called hackamores,[4] though the term "bitless bridle" has become a popular colloquialism in recent years.

The riders of early domesticated horses probably used some type of bitless headgear made of sinew, leather, or rope.

[5] There is evidence of the use of bits, located in two sites of the Botai culture in ancient Kazakhstan, dated about 3500–3000 BC.

[8]: 180–181 Throughout history, the need for control of horses in warfare drove extensive innovation in bit design, producing a variety of prototypes and styles over the centuries, from Ancient Greece into modern-day use.

It is the sidepieces and the leverage these rings or shanks use to act on a horse's mouth that determines whether a bit is in the curb or snaffle family, and has a great impact on the severity of the mouthpiece.

Commonly used metals include stainless steel and nickel alloys, which generally do not rust and have a neutral effect on salivation; sweet iron, aurigan and copper, which generally tend to encourage salivation, and aluminum, which is considered drying and is discouraged as a mouthpiece metal.

[11] Depending on the style of bit, pressure can be brought to bear on the bars, tongue, and roof of the mouth, as well as the lips, chin groove and poll.

Snaffle bits most commonly have a single jointed mouthpiece and act with a nutcracker effect on the bars, tongue and occasionally roof of the mouth.

Usually used for correction of specific problems, the gag bit is generally illegal in the show ring[12] and racecourse.