Identification of the Roman snail and its relatives using shell characters.
The Roman snail with a body length of about 10 cm (4 in.) and a shell 5 cm (2 in.) in diameter is the largest European terrestrial snail. Systematically it belongs to the helicid family (Helicidae), a group of rather large terrestrial snails with spherical shells
Roman snails can most easily be encountered in the evening, when they are about crawling around looking for food. Though they are called vineyard snails in many languages, Roman snails usually do not occur in vineyards. They are merely snails of open hedges and bushes on ground rich in lime. Sometimes, Roman snails also appear in settlements and in gardens. However they are not to be counted among the garden pests - they are too rare to inflict any damage, though many Roman snails are able to eat lots of green matter. Roman snails, as are all helicids, are exclusive plant eaters or herbivores. ( More about feeding and nutrition.)
Body parts and Organs: ( More about body parts and organs)
The cumbersome progress of a Roman snail on a way through
the undergrowth reveals the underside of the foot sole. [RN]
Looking at the shape of a Roman snail's body, many characters point in the direction of the systematic group it belongs to - the stylommatophoran land snails, the most highly developed of all snails. Because of its size, the Roman snail is often used as an object in studies and experiments.
A Roman snail's body is easily separated into the soft living body as such and the hard, lifeless shell. The soft body consists of head and foot on one hand, the visceral sac on the other. The foot is used for locomotion, but also for digging; the head instead is the centre of information. There are four tentacles, the two longer ones each provided with an eye at their end.
The visceral sac is shaped like a sack and located on the snail's back. It contains, as its name says, many of the snail's internal organs. It never leaves the protecting shell. Anyway it is protected to the outside by a tissue layer called the mantle, which also produces the shell. The mantle is especially thick and study in the shell mouth or aperture. There is one large hole in it leading into the mantle cavity beyond, in which a network of blood vessels serves for respiration.
Hibernation: ( More about hibernation)
The courtship of the Roman snail. [RN]
Roman snails can become very old for a snail. To be able to survive that long, they have to hibernate, which they do by closing their shell mouth with a calcareous lid and by hiding in an earth hole they have dug themselves before. During hibernation most body functions are largely reduced and after waking up the snail is severely dehydrated and famished.
Reproduction: ( More about reproduction)
Roman snails are hermaphrodites, the are males and females at the same time. Mating among Roman snails is introduced by an extensive courtship, during which the mates may sting each other with a so-called love dart. A Roman snail's eggs are about 2 mm in diameter and are laid in an earth hole dug by the snail in early summer.
The young perform all their development in their egg. A bit less than a month after egg deposition, young snails hatch that resemble fully their adult relatives. They have got a glassy translucent shells and at once crawl around to look for food. Only a little percentage of young survive until maturity, which is usually reached after the second winter. Those few snails, though, may reach many years of age. Scientific measurements in Bavaria have revealed snails with a natural age of little less than twenty years.
Allotments in a snail farm in Elgg (Switzerland). [RN]
Economy: ( More about economy)
The tasty Roman snails, called "Escargots de Bourgogne" in French, probably have been picked to be eaten since prehistoric times. Only picking them more than for personal needs but for sale, has taken the Roman snail just short of extinction. In most countries it was once abundant, the snails today are very rare.
Roman snails mostly are protected today and picking them from nature is forbidden by law. But both Helix pomatia and its relative, the brown garden snail (Cornu aspersum), are cultivated on snail farms (Hélicicultures). Next to France, also Germany and Switzerland have become a new centre for the ecological, as well as the economical, cultivation of snails.
Relatives: ( More about the Roman snail's relatives).
The next relatives of Roman snails are called helicids (Helicidae). Among them are the colourful and variable banded snails (e.g. Cepaea nemoralis), the brownish spotted copse snail (Arianta arbustorum) and the special looking lapidary snail (Helicigona lapicida).