Logo with three wild equids home page button Mechanical Digestion
 Mechanical Digestion takes place in the mouth and includes saliva, teeth, and the tongue. The large pieces of food that are ingested have to be broken into smaller particles. This is mechanical digestion, which begins in the mouth with chewing or mastication and continues with churning and mixing actions in the stomach.

equid skull Teeth
Mammals are heterodonts, which means they have teeth of different shapes. In fish and reptiles, the teeth are all basically the same, some bigger than others but, the same basic shape. Teeth that are basically the same shape are called homodont. Most mammals have two sets of teeth, the first set comes when they are young soon after birth this first set is often called milk teeth. The scientific term for this is ′diphyodonty′,a term derived from Greek words meaning "twofold production of teeth.". The second is larger set and has more teeth. In non-diphyodont toothed vertebrates teeth just keep growing.

Kinds of teeth
There are four basic kinds of teeth in an individual's jaw, incisors, canines, premolars, and molars. Incisors are used like pincers for grasping, picking or gnawing. Canines are most often used for stabbing, fighting or holding prey. In many herbivores, or plant eaters, canines are often small in size or missing altogether. Premolars vary in size and shape according to how they are used. Some premolars are small and peg-like while others are huge. Premolars are different from molars in that premolars are milk teeth ie. shed and replaced. Molars vary in size, shape, and function just like premolars, but they are not shed for larger adult teeth. Some mammals may not have all their molars until adulthood when the last of their molar teeth erupt.

The names of cheek teeth
Cheek teeth can be grouped by their characteristics.
 The presence of many molars and the absence of canines usually indicate an animal is herbivorous. Many herbivorous mammals possess a diastema (gap) between the incisors and molars. Usually it is because the incisors are enlarged to form "chisels" used for cutting or gnawing.

Equine Dental formula Dental formula Dental formula
Dental formulas indicate the number of each kind of tooth: incisor (I), canine (C), premolar (P), and the molar (M).

The number of teeth of each type is written as a dental formula for one side of the mouth.

In the example to the right only numbers 1 and 4 or 2 and 3. The upper and lower teeth are written on separate rows. The total number of teeth in a mouth is twice of that listed in a dental formula.

In each set, the first number indicates incisors (I), the second, canines (C), the third, premolars (P), and the last, molars (M).For equids the adult dental formula is:
(male)
(I)3.(C)1.(P)3-4.(M)3
(I)3.(C)1.(P)3.(M)3
(female)
(I)3.(C)0.(P)3-4.(M)3
(I)3.(C)0.(P)3.(M)3

In the formula above we see (P)3-4 sometimes written as 3(4) what does the 3-4 mean?
These premolars are called wolf teeth. "Wolf teeth" in a horse are actually vestigial premolars. It is usually only present in the upper jaw. The reason why these vestigial premolars are written in such a way is because they may or may not be visable. The reason for that could be any number of things. The vestigial premolar may have been shed, knocked out or it may have never erupted above the gum line. In domestic horses this tooth can be worn down by the bit or sometimes removed.

Skull shape
Different styles of chewing require different arrangements of muscles that control jaw movement. The muscles attach to the skull to perform the mechanical breakdown of food. Without the muscles, study skulls may appear to have bizarre shapes until you understand how the skull and muscles are attached to each other. There is little to no difference in the shape of domestic and wild equids skulls as both wild and domestic equine's have the same bone and muscle mechanics.

Ingestion
Equids use their upper lip to grasp vegetation and their tongues moves the plant material so the incisors can nip it off. The tongue holds the wad of food against the cheek teeth on one side. A equine's chewing motion is outside-to-inside on a slant determined by the matching surfaces of the upper and lower molars and premolars. Chewing turns the mass into a tube-shaped wad covered with saliva. The wad of food is turned around inside by equine's mouth by the tongue and teeth. As it works its way down the molars the vegetation is ground smaller and smaller until it is swallowed.