![]() The mucus that land snails secrete with the foot leaves a slime trail behind them, which is often visible for some hours afterwards as a shiny "path" on the surface over which they have crawled. They also secrete mucus from the foot to aid in locomotion by reducing friction, and to help reduce the risk of mechanical injury from sharp objects, meaning they can crawl over a sharp edge like a straight razor and not be injured. Snails secrete mucus externally to keep their soft bodies from drying out. Snails move at a proverbially low speed (1 mm/s is a typical speed for adult Helix lucorum ). This muscular action is clearly visible when a snail is crawling on the glass of a window or aquarium. This motion is powered by succeeding waves of muscular contractions that move down the ventral of the foot. ![]() Land snails move by gliding along on their muscular foot, which is lubricated with mucus and covered with epithelial cilia. Underside of a snail climbing a blade of grass, showing the muscular foot and the pneumostome or respiratory pore on the animal's right side They are used as food by humans in various cultures worldwide, and are raised on farms in some areas for use as food.īiology Physical characteristics Most land snails have shells that are right-handed in their coiling.Ī wide range of different vertebrate and invertebrate animals prey on land snails. Tiny snails hatch out of the egg with a small shell in place, and the shell grows spirally as the soft parts gradually increase in size. In terms of reproduction, many caenogastropod land snails (e.g., diplommatinids) are dioecious, but pulmonate land snails are hermaphrodites (they have a full set of organs of both sexes) and most lay clutches of eggs in the soil. Their internal anatomy includes a radula and a primitive brain. Like other mollusks, land snails have a mantle, and they have one or two pairs of tentacles on their head. Land snails have a strong muscular foot they use mucus to enable them to crawl over rough surfaces and to keep their soft bodies from drying out. Many of these operculate land snails live in habitats or microhabitats that are sometimes (or often) damp or wet, such as in moss. The largest clade of land snails is the Cyclophoroidea, with more than 7,000 species. Most of the non-pulmonate land snails belong to lineages in the Caenogastropoda, and tend to have a gill and an operculum. The majority of land snails are pulmonates that have a lung and breathe air. Land snails are a polyphyletic group comprising at least ten independent evolutionary transitions to terrestrial life (the last common ancestor of all gastropods was marine). However, it is not always easy to say which species are terrestrial, because some are more or less amphibious between land and fresh water, and others are relatively amphibious between land and salt water. Land snail is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as slugs). A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails.
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