SNAILS

The name snail applies to most members of the molluscan Class Gastropoda that have coiled shells. Other gastropods, which lack a conspicuous shell, are commonly called slugs, and are scattered throughout groups that primarily include snails. Snails are found in freshwater, marine, and terrestrial environments.

Snails move like worms by alternating body contractions with stretching, with a proverbially low speed (hence the term snail mail for postal services). They produce a slime in order to aid locomotion by reducing friction. The slime also reduces the snail's risk of injury and helps keep away potentially dangerous insects like ants. When retraced into their shells, snails cover the entrance with a 'trapdoor' like structure called an operculum.

In winter some snail species hibernate in their shells by closing the opening with a thin shell-like plate that they build only for this use and destroy in spring. Even some slug species build a shell-like object below their upper skin.

Snails come in a range of different sizes. The largest land snail is the Giant African Snail (Achatina fulica; Family Achatinidae), which can measure up to 30cm. Pomacea maculata (Family Ampullariidae), or Giant Apple Snail is the largest freshwater snail, with its size reaching 15 cm diameter and over 600 g weight. The biggest of all snails is Syrinx aruanus, a marine species living in Australia. Shell lengths up to 1 m have been reported.

Snail shells, like those of the Nautilus, are an example of the appearance of the phi, the golden ratio, in nature.

As one of the largest classes of animals, snails can be found throughout the world. They are found in freshwater, marine, and terrestrial environments. The majority of the world's snails live in the oceans and new species are being discovered regularly. Terrestrial snails prefer damp areas around vegetation which they can use for cover during the day.

A snail's diet varies by species. Terrestrial snails such as garden snails generally eat young plant shoots or bark, or decaying vegetative matter. Carnivorous snails, such as the Decollate Snail feed on other snails. Snails eat by using their radula, or scraping tongue, to shear their food.

Snails, like many worms, are hermaphrodites, producing both sperm and eggs. Prolific breeders, snails exchange sperm with one another to fertilize their eggs. Each brood may consist of up to 100 eggs.

Garden snails bury their eggs in shallow topsoil primarily while the weather is warm and damp. After 2 to 4 weeks of favorable weather, these eggs hatch and the young emerge. Snails may lay eggs as often as once a month.

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