Land snail

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).

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.

Land snails move by gliding along on their muscular foot, which is lubricated with mucus and covered with epithelial cilia.

[12] 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.

Snails (like all molluscs) also have a mantle, a specialized layer of tissue which covers all of the internal organs as they are grouped together in the visceral mass.

When they are active, the organs such as the lung, heart, kidney, and intestines remain inside the shell; only the head and foot emerge.

The shell grows with them in size by the process of secreting calcium carbonate along the open edge and on the inner side for extra strength.

When retracted into their shells, many snails with gills (including some terrestrial species) are able to protect themselves with a door-like anatomical structure called an operculum.

This structure is very much simpler than the brains of mammals, reptiles and birds, but nonetheless, snails are capable of associative learning.

To stay moist during hibernation, a snail seals its shell opening with a dry layer of mucus called an epiphragm.

The great majority of land snails are hermaphrodites with a full set of reproductive organs of both sexes, able to produce both spermatozoa and ova.

A few groups of land snails such as the Pomatiidae, which are distantly related to periwinkles, have separate sexes: male and female.

In a number of different families of land snails and slugs, prior to mating one or more love darts are fired into the body of the partner.

Garden snails bury their eggs in shallow topsoil primarily while the weather is warm and damp, usually 5 to 10 cm down, digging with their foot.

The diet of most land snails can include leaves, stems, soft bark, fruit, vegetables, fungi and algae.

They may have a specialized crop of symbiotic bacteria that aid in digestion, especially with the breakdown of the polysaccharide cellulose into simple sugars.

Some animals, such as the song thrush, break the shell of the snail by hammering it against a hard object, such as stone, to expose its edible insides.

Invertebrate predators include decollate snails, ground beetles, leeches, certain land flatworms such as Platydemus manokwari[31] and even the predatory caterpillar Hyposmocoma molluscivora.

Pollution and habitat destruction have caused the extinction of a considerable number of snail species in recent years.

During unfavourable conditions, a snail remains inside its shell, usually under rocks or other hiding places, to avoid being discovered by predators.

[citation needed] However, wild-caught land snails which are prepared for the table but are not thoroughly cooked, can harbor a parasite (Angiostrongylus cantonensis) that can cause a rare kind of meningitis.

The recipe is identical to this prepared in Andalusia (South Spain), showing the close cultural relationship between both kinds of cuisine.

Mainly three species, all from the family Helicidae, are ordinarily eaten: Snails are a delicacy in French cuisine, where they are called escargots.

[44] In an English-language menu, escargot is generally reserved[citation needed] for snails prepared with traditional French recipes (served in the shell with a garlic and parsley butter).

Bigger varieties, called caracoletas (especially, Cornu aspersum), are generally grilled and served with a butter sauce, but other dishes also exist such as feijoada de caracóis.

There are even snail celebrations, such as the "L'Aplec del Caragol", which takes place in Lleida each May and draws more than 200,000 visitors from abroad.

The bigger ones may be reserved for more elaborate dishes, such as the "arroz con conejo y caracoles" (a paella-style rice with snails and rabbit meat, from the inner regions of south-eastern Spain), "cabrillas" (snails in spicy tomato sauce, typical of western Andalusia) and the Catalan caragols a la llauna (grilled inside their own shells and then eaten after dipping them in garlic mayonnaise) and a la gormanda (boiled in tomato and onion sauce).

Snails (or bebbux as they are called in Maltese) are a dish on the Mediterranean island of Malta, generally prepared and served in the Sicilian manner.

They were collected from quarries and along the stone walls of railway embankments during the winter when the snails were hibernating and had voided the contents of their guts.

In New Caledonia, Placostylus fibratus (French: bulime) is considered a highly prized delicacy and is locally farmed to ensure supplies.