Snail

Snail is a common name for almost all members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in a general sense, it includes sea snails, land snails and freshwater snails. Otherwise snail-like creatures that lack a shell (or have only a very small one) are called slugs.

Snails can be found in a wide range of environments including ditches, deserts, and the abyssal depths of the sea. Although most people are familiar with terrestrial snails, land snails are in the minority. Marine snails constitute the great majority of snail species and have much greater diversity and a greater biomass. Numerous kinds of snail can also be found in fresh water. Many snails are herbivorous, though a few land species and many marine species are omnivores or predatory carnivores.

Snails that respire using a lung belong to the group Pulmonata, while those with gills form a paraphyletic group; in other words, snails with gills are divided into a number of taxonomic groups that are not very closely related. Snails with lungs and with gills have diversified widely enough over geological time that a few species with gills can be found on land, numerous species with a lung can be found in freshwater, and a few species with a lung can be found in the sea.

Snails have thousands of tooth-like stuctures. These thousands of tiny teeth are located on a ribbon-like tongue and work like a file and rip the food to bits. The tongue is called a radula.