Kiss - Biology and Evolution

Biology and Evolution

Within the natural world of animals there are numerous analogies, notes Crawley, such as "the billing of birds, the cataglottism of pigeons and the antennal play of some insects." Even among higher animals such as the dog, cat and bear, similar behavior is noted.

Anthropologists have not reached a conclusion as to whether kissing is learned or a behavior from instinct. It may be related to grooming behavior also seen between other animals, or arising as a result of mothers premasticating food for their children. Non-human primates also exhibit kissing behavior. Dogs, cats, birds and other animals display licking, nuzzling, and grooming behavior among themselves, but also towards humans or other species. This is sometimes interpreted by observers as a type of kissing.

Kissing in humans is postulated to have evolved from the direct mouth-to-mouth regurgitation of food (kiss feeding) from parent to offspring or male to female (courtship feeding) and has been observed in numerous mammals. The similarity in the methods between kiss-feeding and deep human kisses (e.g. French kiss) are quite pronounced, in the former, the tongue is used to push food from the mouth of the mother to the child with the child receiving both the mother's food and tongue in sucking movements, and the latter is the same but forgoes the premasticated food. In fact, through observations across various species and cultures, it can be confirmed that the act of kissing and premastication has most likely evolved from the similar relationship-based feeding behaviours.