Snails can only crawl. Even those that live in water can't swim. As they crawl they secrete a slime to help themselves move across surfaces. The snail's head bears the mouth opening and one or two pairs of tentacles. The eyes are located at the base of the tentacles.
Most snails live off plants and dead organic matter, although a few are carnivorous.
Their radula is a tongue-like projection of their mouth which is lined with small sharp teeth. Some snails obtain food by using their radula to drill holes in the shells of other mollusks. Freshwater snails and land snails have been eaten by people since prehistoric times. Today they are still regarded as a delicacy in many countries. The market supply comes largely from snails that are raised in captivity on special farms in southern France, Italy, and Spain.