Drinking

Drinking is the act of ingesting water or other liquids into the body through the mouth. Water is required for many of life’s physiological processes. Both excessive and inadequate water intake are associated with health problems.

When a liquid is poured into an open human mouth, the swallowing process is completed by peristalsis which delivers the liquid to the stomach; much of the activity is abetted by gravity. The liquid may be poured from the hands or drinkware may be used as vessels. Drinking can also be performed by acts of inhalation, typically when imbibing hot liquids or drinking from a spoon. Infants employ a method of suction wherein the lips are pressed tight around a source, as in breastfeeding: a combination of breath and tongue movement creates a vacuum which draws in liquid.

Amphibians and aquatic animals which live in freshwater do not need to drink: they absorb water steadily through the skin by osmosis.Saltwater fish, however, drink through the mouth as they swim, and purge the excess salt through the gills.

By necessity, terrestrial animals in captivity become accustomed to drinking water, but most free-roaming animals stay hydrated through the fluids and moisture in fresh food. When conditions impel them to drink from bodies of water, the methods and motions differ greatly among species. Many desert animals do not drink even if water becomes available, but rely on eating succulent plants.

Cats, canines, and ruminants all lower the neck and lap in water with their powerful tongues. Cats and canines lap up water with the tongue in a spoon-like shape. Ruminants and most other herbivores partially submerge the tip of the mouth in order to draw in water by means of a plunging action with the tongue held straight. Cats drink at a significantly slower pace than ruminants, who face greater natural predation hazards. Uniquely, elephants draw water into their trunks and squirt it into their mouths.

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Wikipedia