Mastication

( Also referred to as mastication ) chew is a mechanical process which is used for crushing of the food and the first enzymatic decomposition ( digestion). This results in the " up-down movement " in combination with a lateral movement of the mandible. Thus, the food present in the mouth is transported with the tongue between the molars and crushed by them. During chewing the food is mixed with saliva.

The chewing swallowing, wherein said food mass is conveyed through the esophagus into the following digestive tract.

Most vertebrates can not chew, no fish, amphibians and birds. About snakes swallow their prey down without chewing. Other animals tear out pieces from the prey animals, such as birds of prey or crocodiles. Many mammals can not chew, such as the echidna also. Also, most predators such as dogs and cats chew their food very little and choke down larger pieces.

Particularly pronounced chewing is, however, in the cattle -like chewing ruminants as their food twice, by conveying the pre-digested chyme from the stomach through the esophagus into the mouth again. The necessity of chewing depends strong manner by the food from, the cellulosic is, for example, as grass, bark, etc., the more important is the mechanical crushing of the food.

Herbivores that have not formed the evolutionary advantage of chewing in the mouth by molars, are dependent on aggressive digestive juices and swallowed stones, which take over the mechanical comminution of the plant fibers.

The pathological chewing the fingernails in humans is called onychophagia.