Licking

Licking is the action of passing the tongue over a surface, typically either to deposit saliva onto the surface, or to collect liquid, food or minerals onto the tongue for ingestion, or to communicate with other animals. Many animals both groom themselves and eat or drink by licking.

Grooming: Animals commonly clean themselves through licking. In mammals, licking helps keep the fur clean and untangled. The tongues of many mammals have a rough upper surface that acts like a brush when the animal licks its fur. Certain reptiles, such as geckos, clean their eyes by licking them.

Mammals typically lick their offspring clean immediately after birth; in many species this is necessary to free the newborn from the amniotic sac. The licking not only cleans and dries the offspring's fur, but also stimulates its breathing and digestive processes.

Food and water acquisition: Hummingbirds are often said to "sip" nectar, but in fact they up nectar on their long tongues. Their tongues have fringed edges, which help both in nectar-eating and in catching tiny insects. Mother hummingbirds also lick their chicks after a rainstorm to dry them by licking water droplets from the coats of the chicks to avoid them chilling. Many animals drink by licking. While young mammals drink milk from their mothers' teats by sucking, the typical method of drinking for adult mammals involves dipping the tongue repeatedly into water and using it to scoop water into the mouth. This method of drinking relies in part on the water adhering to the surface of the tongue and in part on muscular control of the tongue to form it into a spoonlike shape. Cattle, horses and other animals lick rocks, salt licks or other objects to obtain mineral nutrients.

Gustation: Animals also use their tongues to enhance their sense of smell. By licking a surface or extending the tongue beyond the mouth, molecules are transferred via the tongue to the olfactory receptors in the nose and in some animals, to the vomeronasal organ. In some mammals, the tongue is used to "lick" the air during the flehmen response to assist transfer of pheremones. Similarly, snakes use smell to track their prey. They smell by using their forked tongues to collect airborne particles, then passing them to the vomeronasal organ. They keep their tongues constantly in motion, sampling particles from the air, ground, and water, analyzing the chemicals found, and determining the presence of prey or predators in the local environment.

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