Snail

Snail, any of as many as 50,000 marine, freshwater, and terrestrial species of mollusk. Gastropods (literally, belly-footed animals) have been able to adapt their singular means of locomotion to a wide range of water and land habitats, from the depths and shorelines of oceans to all bodies of fresh water, and from tropical areas to mountains and deserts.

Snails move by means of a wavelike series of muscular contractions along the bottom of the foot. This motion is often aided by cilia and, in land snails, by a track of laid-down slime. Snails feed mainly on algae and decaying matter and are important members of the food web, being a source of food to fish and waterfowl. A snail browses by means of a radula, a ribbonlike tongue often containing many thousands of denticles, or teeth, that are projected from the mouth opening and drawn along rocks or leaves. Some carnivorous snails have radulae that bore holes through the shells of other mollusks to reach the soft flesh. Many species of snails are hermaphroditic and capable of self-fertilization.

Snails have prominent tentacles on which, in many species, the eyes are often located. Many snails are as small as 0.1 cm (0.04 in) long; others, such as conchs and the African land snail, are as long as 20 cm (8 in). The spiral shell into which the snail withdraws serves mainly as protection against predators and desiccation. Land snails are particularly well adapted to changes in moisture; some desert species are able to remain sealed within their thick shells for two or more years. Land snail species of more moist habitats usually have thinner shells; slugs, which live in very moist places and are often considered snails, have only vestigial shells.

Escargots, the snails of French cuisine, come from the cultivated land snail. Other edible snails are the abalone of California and Japan, the periwinkle of Europe and South Africa, and the queen conch of the West Indies.

Scientific classification: Snails belong to the class Gastropoda. The African land snail is classified as Achatina fulica, and the cultivated land snail as Helix pomatia. Abalones are classified in the genus Haliotis and periwinkles in the genus Littorina. The queen conch is classified as Strombus gigas.