A land snail is any of the numerous species of snail that live on
land, as opposed to sea snails and freshwater snails.
Land snail is
the common name for terrestrial gastropod mollusks that have shells
(those without shells are known as slugs). However, it is not always
easy to say which species are terrestrial, because some are more or
less amphibious between land and freshwater, and others are relatively
amphibious between land and saltwater.
The majority of land snails are pulmonates. That is, they have a lung
and breathe air. A minority however belong to much more ancient
lineages where their anatomy includes a gill and an operculum. Many of
these operculate land snails live in habitats or microhabitats that
are sometimes (or often) damp or wet, such as for example in moss.
Land snails have a strong muscular foot; they use mucus to enable them
to crawl over rough surfaces and in order to keep their soft bodies
from drying out. Like other mollusks, land snails have a mantle, and
they have one or two pairs of tentacles on their head. Their internal
anatomy includes a radula and a primitive brain. In terms of
reproduction, the majority of land snails are hermaphrodite (have a
full set of organs of both sexes) and most lay clutches of eggs in the
soil. 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. Most land snails have shells that are right-handed in their
A wide range of different vertebrate and invertebrate animals prey on
land snails, and they are used as food by humans in various cultures
worldwide, and are even raised on farms as food in some areas.
1.1 Physical characteristics
1.2 Internal anatomy
1.3 Growth of the shell
Hibernation and estivation
2 Snails as human food
3 See also
5 External links
"The Teeth of a Snail" from Robert Hooke's Micrographia, 1665. This
actually shows the jaw, against which the teeth on the radula act.
Sphincterochila boissieri in Hamakhtesh Hagadol, northern Negev.
Diameter is 2.1 cm.
Underside of a snail climbing a blade of grass, showing the muscular
foot and the pneumostome or respiratory pore on the animal's right
Land snails move by gliding along on their muscular foot, which is
lubricated with mucus and covered with epithelial cilia. This
motion is powered by succeeding waves of muscular contractions that
move down the ventral of the foot. This muscular action is clearly
visible when a snail is crawling on the glass of a window or
aquarium. Snails move at a proverbially low speed (1 mm/s is a
typical speed for adult Helix lucorum). Snails secrete mucus
externally to keep their soft bodies from drying out. 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. 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
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. The mantle also extends outward in
flaps which reach to the edge of the shell and in some cases can cover
the shell, and which are partially retractable. The mantle is attached
to the shell, and creates the shell and makes shell growth possible by
Most molluscs, including land snails, have a shell which is part of
their anatomy since the larval stage, and which grows with them in
size by the process of secreting calcium carbonate along the open edge
and on the inner side for extra strength. Although some land snails
create shells that are almost entirely formed from the protein
conchiolin, most land snails need a good supply of calcium in their
diet and environment to produce a strong shell. A lack of calcium, or
low pH in their surroundings, can result in thin, cracked, or
perforated shells. Usually a snail can repair damage to its shell over
time if its living conditions improve, but severe damage can be fatal.
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.
Land snails range greatly in size. The largest living species is the
Snail (Achatina achatina; Family
Achatinidae), which can measure up to 30 cm. The largest
land snails of non-tropical Eurasia are endemic Caucasian snails Helix
Helix goderdziana from the south-eastern
Black Sea area in
Georgia and Turkey; diameter of the shell of the latter may exceed
6 cm 
Most land snails bear one or two pairs of tentacles on their heads. In
most land snails the eyes are carried on the first (upper) set of
tentacles (called ommatophores or more informally 'eye stalks') which
are usually roughly 75% of the width of the eyes. The second (lower)
set of tentacles act as olfactory organs. Both sets of tentacles are
retractable in land snails.
Light micrograph of a section through a snail's eye (Helix pomatia). 1
anterior chamber, 2 lens in the posterior chamber, 3 retina, 4 optic
The anatomy of a common snail
Helix aspersa defecating
A snail breaks up its food using the radula inside its mouth. The
radula is a chitinous ribbon-like structure containing rows of
microscopic teeth. With this the snail scrapes at food, which is then
transferred to the digestive tract. In a very quiet setting, a large
land snail can be heard 'crunching' its food: the radula is tearing
away at the surface of the food that the snail is eating.
The cerebral ganglia of the snail form a primitive brain which is
divided into four sections. This structure is very much simpler than
the brains of mammals, reptiles and birds, but nonetheless, snails are
capable of associative learning.
Growth of the shell
As the snail grows, so does its calcium carbonate shell. The shell
grows additively, by the addition of new calcium carbonate, which is
secreted by glands located in the snail's mantle. The new material is
added to the edge of the shell aperture (the opening of the shell).
Therefore, the centre of the shell's spiral was made when the snail
was younger, and the outer part when the snail was older. When the
snail reaches full adult size, it may build a thickened lip around the
shell aperture. At this point the snail stops growing, and begins
A snail's shell forms a logarithmic spiral. Most snail shells are
right-handed or dextral in coiling, meaning that if the shell is held
with the apex (the tip, or the juvenile whorls) pointing towards the
observer, the spiral proceeds in a clockwise direction from the apex
to the opening.
Snail with a rightwardly spiraling shell
Sinistral (left-handed) species of snail from western India
Hibernation and estivation
Some snails hibernate during the winter (typically October through
April in the Northern Hemisphere). They may also estivate in the
summer in drought conditions. To stay moist during hibernation, a
snail seals its shell opening with a dry layer of mucus called an
The use of love darts by the land snail
Monachoides vicinus is a form
of sexual selection
Two Helicid snails make contact prior to mating.
Helix pomatia snails mating
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; they are male
and female. The age of sexual maturity is variable depending on
species of snail, ranging from as little as 6 weeks  to 5
years. Adverse environmental conditions may delay the onset of
sexual maturity in some snail species.
Prior to reproduction, most pulmonate air breathing land snails
perform courtship behaviors before mating. The courtship may last
anywhere between two and twelve hours. 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.
Prolific breeders, pulmonate land snails inseminate each other in
pairs to internally fertilize their ova via a reproductive opening on
one side of the body, near the front, through which the outer
reproductive organs are extruded so that exchange of sperm can take
place. Fertilization then occurs and the eggs develop. 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, usually 5 to 10 cm down, digging with
their foot. Egg sizes differ between species, from a 3 mm
diameter in the grove snail to a 6 mm diameter in the Giant
African Land Snail. After 2 to 4 weeks of favorable weather, these
eggs hatch and the young emerge. Snails may lay eggs as often as once
The snail's shell develops while it is still an embryo; it is,
however, very weak, and needs an immediate supply of calcium. Newly
hatched snails obtain this by eating the egg from which they hatched.
The cannibalization by baby snails of other eggs, even unhatched ones,
has been recorded. Promptly after they are finished ingesting their
egg casings, they crawl upwards through the small tunnel in order to
digest the egg. At this stage, the young are almost completely
transparent and colorless. Their shell is usually slightly smaller
than the egg they hatched from, but their length when out of their
shell is slightly greater than the egg diameter. After a few weeks,
the snails will begin to show their first tinge of color, usually
slightly blue, before they turn their adult color. Roughly three
months after they have hatched, they will look like miniature versions
of their mature kin. They will continue to grow, usually for two to
three years, until they reach adult size, although there have been
confirmed recordings of snails growing amazingly fast – becoming
even bigger than their parents in little more than a month.[citation
There have been hybridizations of snail species; although these do not
occur commonly in the wild, in captivity they can be coaxed into doing
Parthenogenesis has been reported only in one species of slug, but
many species can self-fertilise.
Most species of land snail are annual, others are known to live 2 or 3
years, but some of the larger species may live over 10 years
in the wild. For instance, 10-year old individuals of the Roman
Helix pomatia are probably not uncommon in natural
populations. Populations of some threatened species may be
dependent on a pool of such long-lived adults. In captivity, the
lifespan of snails can be much longer than in the wild, for instance
up to 25 years in H. pomatia.
In the wild, snails eat a variety of different foods. Terrestrial
snails are usually herbivorous, however some species are predatory
carnivores or omnivores, including the genus Powelliphanta, which
includes the largest carnivorous snails in the world, native to New
Zealand. The diet of most land snails can include leaves, stems,
soft bark, fruit, vegetables, fungi and algae. Some species can cause
damage to agricultural crops and garden plants, and are therefore
often regarded as pests.
The larva of a glowworm (Lampyris noctiluca) attacking and eating a
In an attempt to protect themselves against predators, land snails
retract their soft parts into their shell when they are resting; some
bury themselves. Land snails have many natural predators, including
members of all the land vertebrate groups, three examples being
thrushes, hedgehogs and
Pareas snakes. Invertebrate predators include
decollate snails, ground beetles, leeches, certain land flatworms such
as Platydemus manokwari and even the predatory caterpillar
In the case of the marsh snail Succinea putris, the snails can be
parasitized by a microscopic flatworm of the species Leucochloridium
paradoxum, which then reproduces within the snail's body. The
flatworms invade the snail's eye stalks, causing them to become
enlarged. Birds are attracted to and consume these eye stalks,
consuming the flatworms in the process and becoming the final hosts of
Human activity poses great dangers to snails in the wild. Pollution
and habitat destruction have caused the extinction of a considerable
number of snail species in recent years.
Snails as human food
Snail § As food
A snail farm in Provence
Land snails have been eaten for thousands of years, going back at
least as far as the Pleistocene. Archaeological evidence of snail
consumption is especially abundant in Capsian sites in North Africa,
but is also found throughout the Mediterranean region in
archaeological sites dating between 12,000 and 6,000 years
ago. 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
Snail eggs, sold as snail caviar, are a specialty food that is growing
in popularity in European cuisine.
Achatina fulica, the giant east African snail, is canned and sliced
and sold to consumers as escargot.
In parts of West Africa, specifically Ghana, snails are served as a
delicacy. Achatina achatina,
Ghana tiger snails, are also known as
some of the largest snails in the world.
In Cameroon, snails, usually called 'nyamangoro' and 'slow boys' are a
delicacy especially to natives of the South West region of Cameroon.
The snails are either eaten cooked and spiced or with a favourite dish
In North Morocco, small snails are eaten as snacks in spicy soup. The
recipe is identical to this prepared in
Andalusia (South Spain),
showing the close cultural relationship between both kinds of cuisine.
Snails are eaten in several European countries, as they were in the
past in the Roman Empire. Mainly three species, all from the family
Helicidae, are ordinarily eaten:
Helix pomatia, or edible snail, generally prepared in its shell, with
parsley butter (size: 40 to 55 mm for an adult weight of 25 to
45 g.; typically found in Burgundy, France; known as l'Escargot
Helix lucorum, found throughout the
Eastern Mediterranean region are
commonly eaten in
Greece and in some rural communities (ethnic Greeks
and Georgian Catholics) in Georgia.
Cornu aspersum, synonym Helix aspersa:
Cornu aspersum, better known as the European brown snail, is cooked in
many different ways, according to different local traditions (size: 28
to 35 mm for an adult weight of 7 to 15 g.; typically found
in the Mediterranean countries of
North Africa and the
French Atlantic coast;
Helix aspersa aspersa known as le Petit-gris).
Cornu aspersum maxima (size 40 to 45 mm for an average weight of
20 to 30 g.; typically found in North Africa).
Snails are a delicacy in French cuisine, where they are called
escargots. 191 farms produced Escargots in
France as of 2014. In
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). Before preparing snails
to eat, the snails should be fasting for three days with only water
available. After three days of fasting, the snails should be fed flour
and offered water for at least a week. This process is thought to
cleanse the snails.
Portuguese caracóis snack, species Theba pisana.
Snails are also popular in
Portuguese cuisine where they are called in
Portuguese caracóis, and served in cheap snack houses and taverns,
usually stewed (with different mixtures of white wine, garlic, piri
piri, oregano, coriander or parsley, and sometimes chouriço). 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. Overall,
about 4,000 tonnes of snails each year.
Cooked French escargots, species Helix pomatia
Cooked Spanish "caracoles a la madrileña", species Helix aspersa
Spanish cuisine also uses snails ("caracoles" in Spanish;
"caragols" or "cargols" in Catalan), consuming several species such as
Helix aspersa, Otala lactea,
Otala punctata or
Theba pisana among
others. Snails are very popular in Andalusia, Valencia and Catalonia.
There are even snails celebration, as the "L’Aplec del Caragol",
which takes place in
Lleida each May and draws more than 200,000
visitors from abroad.
Small to medium-size varieties are usually cooked in several spicy
sauces or even in soups and eaten as appetizer. The bigger ones may be
reserved for other more elaborated 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 from western Andalusia) or 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).
In Greece, snails are especially popular in the island of Crete, but
are also eaten in many parts of the country and can even be found in
supermarkets, sometimes placed alive near partly refrigerated
vegetables. In this regard, snails are one of the few live organisms
sold at supermarkets as food. They are eaten either boiled with
vinegar added, or sometimes cooked alive in a casserole with tomato,
potatoes and squashes. Limpets and sea snails also find their way to
the Greek table around the country. Another snail cooking method is
the Kohli Bourbouristi (κοχλιοί
μπου(ρ)μπουριστοί) a traditional Cretan dish, which
consists of fried snails in olive oil with salt, vinegar and rosemary.
They feature often in
Cyprus taverna menus, at mezes' section
under the name karaoloi (καράολοι).
In Sicily, snails (or babbaluci as they are commonly called in
Sicilian) are a very popular dish as well. They are usually boiled
with salt first, then served with tomato sauce or bare with oil,
garlic and parsley. Snails are similarly appreciated in other Italian
regions, such as Sardinia.
Snails (or bebbux as they are called in Maltese) are a dish on the
Mediterranean island of Malta, generally prepared and served in the
Germany there is a regional specialty of soup with
snails and herbs, called "Black Forest
Snail Chowder" (Badener
Heliciculture is the farming of snails. Some species such as the Roman
Snail are protected in the wild in several European countries and must
not be collected, but the Roman
Snail and the Garden
aspersum) are cultivated on snail farms.
Although there is not usually considered to be a tradition of snail
eating in Britain, common garden snails
Helix aspersa were eaten in
the Southwick area of Sunderland in North East England. 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. Gibson writes that this tradition
was introduced in the 19th century by French immigrant glass
Snail suppers" were a feature of local pubs and
Southwick working men were collecting and eating snails as late as the
1970s, though the tradition may now have died out.
Bulime cooked in garlic butter in Ile des Pins, New Caledonia, species
In New Caledonia,
Placostylus fibratus (French: bulime) is considered
a highly prized delicacy and is locally farmed to ensure supplies.
It is often served by restaurants prepared in the French style with
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Recipes for snails
Predatory snails on the UF / IFAS Featured Creatures Web site.