The empty space between a horse’s incisors and molars. The soft gum tissue in this area is sensitive. The bit is placed so that it rests in this part of the mouth. Pressure exerted by the bit pressing on the bars causes discomfort and is used to slow a horse’s pace, change his direction, or change his head or body carriage.
Young horses still have wolf teeth (tiny tusks visible in the photo above), which can cause discomfort when the horse is wearing a bit. Generally all male horses have 4 or 5 wolf teeth. However, few female horses (about 25%) have them, and those that do have only 1 or 2 that are sometimes not erupted through the gum and are usually on the upper jaw.
Wolf teeth are not canines as the name suggests, but vestigial (evolutionarily left-over – no longer usefull) premolars.
At maturity, horses have six upper and six lower incisors (front) and a total of 24 permanent molars. Horses, like humans, get two sets of teeth: baby teeth and permanent teeth. The wolf tooth has no deciduous precursor, but many horses lose the wolf teeth naturally at about 2-3 years of age as if they were baby teeth. If they are not lost naturally they are often pulled depending on whether they are likely to interfere with the horse’s use of a bit.
All permanent teeth are generally in by about 5-6 years old.