Ingestion in Mammals

Ingestion is a series of biologically complex activities(capture,incision,transport,mastication,swallowingand,in infant mammals, suckling) performed by the oralapparatus. The oral apparatus includes the dentition, themasticatory muscles, numerous bones of the cranium, thesquamosal–dentary joints connecting the lower jaw to theskull, the tongue, and many other structures in the head.Mammals are distinguished from other vertebrates inmany aspects of ingestion. For example, in most othervertebrates, mastication does not occur. Also, foodtransport and swallowing are less complex in othervertebrates and generally involve the coordination offewer muscles and other soft tissue structures. Further-more,sucklingisabehaviourthatisuniquetomammals.Itis not surprising, therefore, that mammals have manybony, muscular, neural and other specializations foringestion that distinguish them from other vertebrates.Among mammals, interspecific variation in these anato-mical specializations frequently reflects the dominantcomponent of a species’ diet, so that we speak ofherbivores, carnivores, insectivores, frugivores and omni-vores. Structures that are adapted in mammals for useduring ingestion include the dentition, the chewingmuscles, the lips and the lip musculature, the cheekmusculature, the cranial bones, the palate, the tongue,and the pharynx.Thedentitionofmammalsisheterodontic,whichmeansthattheteethdonotalllookalikeastheydoinfish,reptilesand most other vertebrates. Instead, mammals haveincisors, canines, premolars and molars in both the upperand the lower jaw. These tooth types are structurallydifferent and each has a specialized function. The incisorsare at the front of the mouth and are usually spatulate inshape. They are used to grab food items, to break smallpieces offoodawayfrom largerpieces, tokill live prey andto gnaw. In some mammals, for example rodents, thecentral incisors are robust, ever-growing teeth specializedfor gnawing and chiselling (