Mastication is the first stage in the process of digestion. In most mammals, controlled vertical and transverse movements of the mandible, as well as protrusion and retrusion of the tongue characterize mastication.
These controlled movements of the mandible contribute also in swallowing and production of speech. In these functions significant is also the contribution of tongue and certain muscles controlling perioral area, pharynx and larynx.
The controlled movements of mastication are not observed from the initial stages of life. However, some non-synchronized movements of mandible start from embryonic life in all mammals. During neonatal life, several masticatory movements are observed, but most mammals are feeded with sucking. Later a gradual shift of kinetic prototypes of sucking to the prototypes of mastication occurs. Mechanisms controlling this shift are multifactorial and are probably related with maturation of neural and anatomic components.