A land snail is any of the numerous species of snail that live on land, as opposed to the 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 fresh water, and others are relatively amphibious between land and salt water.
76-485: Mandarina is a genus of air-breathing land snail , a terrestrial pulmonate gastropod mollusk in the family Camaenidae , subfamily Bradybaeninae . Mandarina have been traditionally placed within Camaenidae . Phylogenic study by Chiba (1999) have found, that Mandarina is closely related to Euhadra (family Bradybaenidae) and that Mandarina have probably evolved from Euhadra . The genus Mandarina
152-436: 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 secretion. Most molluscs, including land snails, have
228-428: A shell which is part of their anatomy since the larval stage. 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. Although some land snails create shells that are almost entirely formed from
304-646: A butter sauce, but other dishes also exist such as feijoada de caracóis . Overall, Portugal consumes about 4,000 tonnes of snails each year. Traditional Spanish cuisine also uses snails ("caracoles" in Spanish; "caragols" or "cargols" in Catalan), consuming several species such as Cornu aspersum , Otala lactea , Otala punctata and Theba pisana . Snails are very popular in Andalusia , Valencia and Catalonia . There are even snail celebrations, such as
380-494: A coiled shell, the whorls spiral. The central axis passes through the columella, the central pillar of the shell. Among proposed roles invoked for the variability of shells during evolution include mechanical stability, defense against predators and climatic selection. The shells of some gastropods have been reduced or partly reduced during their evolution . This reduction can be seen in all slugs , in semi-slugs and in various other marine and non-marine gastropods. Sometimes
456-532: A delicacy in French cuisine , where they are called escargots . 191 farms produced escargots in France as of 2014. In an English-language menu, escargot is generally reserved 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,
532-654: A delicacy. Achatina achatina , Ghana tiger snails, are also known as some of the largest snails in the world. Snail, called "igbin" in Yoruba language is a delicacy, widely eaten in Nigeria, especially among the Yorubas and Igbos. 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
608-580: A door-like anatomical structure called an operculum . Land snails range greatly in size. The largest living species is the Giant African Snail or Ghana Tiger 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 buchi and Helix goderdziana from the south-eastern Black Sea area in Georgia and Turkey ; diameter of
684-750: 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. The age of sexual maturity varies depending on species of snail, ranging from as little as 6 weeks to 5 years. Adverse environmental conditions may delay sexual maturity in some snail species. Most pulmonate air-breathing land snails perform courtship behaviors before mating. The courtship may last anywhere between two and twelve hours. In
760-492: A favourite dish called 'eru'. 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: Snails are
836-555: 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 coiling. A wide range of different vertebrate and invertebrate animals prey on land snails. They are used as food by humans in various cultures worldwide, and are raised on farms in some areas for use as food. Land snails move by gliding along on their muscular foot , which
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#1732772528702912-405: 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 . Since snails in
988-443: 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. Pulmonate land snails are prolific breeders and 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 sperm can be exchanged. Fertilization then occurs and
1064-669: A popular dish. 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 Piedmont where in Cherasco there is the Italian National Institute of Heliculture. Snails (or bebbux as they are called in Maltese ) are a dish on the Mediterranean island of Malta , generally prepared and served in
1140-465: A rare or abnormal sinistral one. Sinistrality arose independently 19 times among marine gastropods since the start of the Cenozoic . This left-handedness seems to be more common in freshwater and land pulmonates. But still the dextral living species in gastropods seem to account for 99% of the total number. The chirality in gastropods appears in early cleavage ( spiral cleavage ) and the gene NODAL
1216-509: A remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it ( semi-slug ). Some snails also possess an operculum that seals the opening of the shell, known as the aperture , which provides further protection. The study of mollusc shells is known as conchology . The biological study of gastropods, and other molluscs in general, is malacology . Shell morphology terms vary by species group. The gastropod shell has three major layers secreted by
1292-399: A ridge or shelf next to the suture ( Clavilithes ). An outer (lateral) emargination or notch, sometimes prolonged into a slit occurs in certain types (Pleurotomidae, Pleurotomaridae, Bellerophontidae, etc.), and the progressive closing of this slit may give rise to a definitely marked slit band. In some cases the slit is abandoned and left as a hole ( Fissurellidae ), or by periodic renewal as
1368-411: A simple Mendelian recessive. In photographs or illustrations, a gastropod shell can be shown oriented in a number of standard ways: The shell begins with the larval shell, the (usually) minute embryonic whorls known as the protoconch , which is often quite distinct from the rest of the shell and has no growth lines. From the protoconch, which forms the apex of the spire , the coils or whorls of
1444-399: A small minority of species and genera are virtually always sinistral (left-handed), and a very few species (for example Amphidromus perversus ) show a mixture of dextral and sinistral individuals. There occur also aberrantly sinistral forms of dextral species and some of these are highly sought by shell collectors. If a coiled gastropod shell is held with the spire pointing upwards and
1520-468: A strong muscular foot; they use mucus to enable them to crawl over rough surfaces and 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, many caenogastropod land snails (e.g., diplommatinids ) are dioecious , but pulmonate land snails are hermaphrodites (they have
1596-403: A succession of holes ( Haliotis ). The outer emargination is often only indicated by the reflected course of the lines of growth on the shell. On the inside of the outer lip, various ridges or plications called lirae are sometimes found, and these occasionally may be strong and tooth-like ( Nerinea ). Similar ridges or columellar plicae or folds are more often found on the inner lip, next to
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#17327725287021672-459: Is endemic to Ogasawara Islands . The shell is solid. The width of the shell is 15–80 mm. Species within the genus Mandarina include: Mandarina live in various habitats including arboreal , semi-arboreal, ground habitats, wet habitats and dry habitats. 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
1748-510: Is involved. A more recent study (2013) correlates the asymmetric coiling of the shell by the left-right asymmetric expression of the decapentaplegic gene in the mantle. In a few cases, both left- and right-handed coiling are found in the same population. Sinistral mutants of normally dextral species and dextral mutants of normally sinistral species are rare but well documented occurrences among land snails in general. Populations or species with normally mixed coiling are much rarer, and, so far as
1824-555: Is known, are confined, with one exception, to a few genera of arboreal tropical snails. Besides Amphidromus , the Cuban Liguus vittatus (Swainson), Haitian Liguus virgineus (Linnaeus) (family Orthalicidae ), some Hawaiian Partulina and many Hawaiian Achatinella (family Achatinellidae ), as well as several species of Pacific islands Partula (family Partulidae ), are known to have mixed dextral-sinistral populations. A possible exception may concern some of
1900-491: Is layered upon the periostracum as the snail grows. Upper image: Dorsal view, showing whorls and apex Central image: Lateral view showing the profile of the shell Lower image: Basal view showing umbilicus in the centre. Gastropod shell morphology is usually quite constant among individuals of a species. Controlling variables are: Some of these factors can be modelled mathematically and programs exist to generate extremely realistic images. Early work by David Raup on
1976-489: 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
2052-592: Is not usually considered to be a tradition of snail eating in Great Britain , common garden snails Cornu aspersum 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
2128-430: Is secreted by, and attached to, the upper surface of the posterior part of the foot. The operculum is of very variable form in the different groups of snails that possess one. The terminology used to describe the shells of gastropods includes: The overall shape of the shell varies. For example, three groups can be distinguished based on the height – width ratio: The following are the principal modifications of form in
2204-451: Is strong evidence for selfing ( self-fertilization ) in the easternmost snail populations as indicated by microsatellite data. Compared to western populations, in the eastern population mucous gland structures employed in sexual reproduction are highly variable and deformed suggesting that in selfing organisms these structures have reduced function. Most species of land snail are annual, others are known to live 2 or 3 years, but some of
2280-410: Is the maximum measurement of the shell at right angles to the central axis. Both terms are only related to the description of the shell and not to the orientation of the shell on the living animal. The largest height of any shell is found in the marine snail species Syrinx aruanus , which can be up to 91 cm. The central axis is an imaginary axis along the length of a shell, around which, in
2356-892: 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. Snail eggs, sold as snail caviar , are a specialty food that is growing in popularity in European cuisine. Snails contain many nutrients . They are rich in calcium and also contain vitamin B 1 and E . They contain various essential amino acids , and are low in calories and fat . However, wild-caught land snails which are prepared for
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2432-441: The mantle . The calcareous central layer, ostracum, is typically made of calcium carbonate (CaCO 3 ) precipitated into an organic matrix known as conchiolin . The outermost layer is the periostracum which is resistant to abrasion and provides most shell coloration. The body of the snail contacts the innermost smooth layer that may be composed of mother-of-pearl or shell nacre, a dense horizontally packed form of conchiolin, which
2508-593: The olive and Terebra , are smooth, elongated, and lack elaborate sculpture, in order to decrease resistance when moving through sand. On land, high-spired forms are often associated with vertical surfaces, whereas flat-shelled snails tend to live on the ground. A few gastropods, for instance the Vermetidae , cement the shell to, and grow along, solid surfaces such as rocks, or other shells. Most gastropod shells are spirally coiled. The majority (over 90%) of gastropod species have dextral (right-handed) shells, but
2584-461: The " L'Aplec del Caragol ", which takes place in Lleida each May and draws more than 200,000 visitors from abroad. Small to medium-sized varieties are usually cooked in one of several spicy sauces or even in soups, and eaten as an appetizer. 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
2660-526: The European clausiliids of the subfamily Alopiinae . They are obligatory calciphiles living in isolated colonies on limestone outcrops. Several sets of species differ only in the direction of coiling, but the evidence is inconclusive as to whether left- and right-handed shells live together. Soos (1928, pp. 372–385) summarized previous discussions of the problem and concluded that the right- and left-handed populations were distinct species. Others have stated that these populations were not distinct, and
2736-629: The French style with garlic butter. Metaldehyde and iron phosphate can be used to exterminate snails. Since copper generates electric shocks that make it difficult for snails to move, it makes a great barrier material for them. Gastropod shell The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton , which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less ( slugs ) but may have
2812-678: The Sicilian manner. In southwestern Germany there is a regional specialty of soup with snails and herbs, called "Black Forest Snail Chowder" ( Badener Schneckensuepple ). 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 Snail ( Cornu aspersum ) are cultivated on snail farms. Although there
2888-548: The analog computer also revealed many possible combinations that were never adopted by any actual gastropod. Some shell shapes are found more often in certain environments, though there are many exceptions. Wave-washed high-energy environments, such as the rocky intertidal zone, are usually inhabited by snails whose shells have a wide aperture, a relatively low surface area, and a high growth rate per revolution. High-spired and highly sculptured forms become more common in quiet water environments. The shell of burrowing forms, such as
2964-412: The aperture more or less facing the observer, a dextral shell will have the aperture on the right-hand side, and a sinistral shell will have the aperture on the left-hand side. This chirality of gastropods is sometimes overlooked when photographs of coiled gastropods are "flipped" by a non-expert prior to being used in a publication. This image "flipping" results in a normal dextral gastropod appearing to be
3040-468: The breakdown of the polysaccharide cellulose into simple sugars. Some species can cause damage to agricultural crops and garden plants, and are therefore often regarded as pests . Many predators, both specialist and generalist, feed on snails. 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. Other predators, such as some species of frogs , circumvent
3116-418: The columella or central spiral twist. These may be oblique or normal to the axis of coiling (horizontal), few or numerous, readily seen, or far within the shell so as to be invisible except in broken shells. When the axis of coiling is hollow (perforate spire) the opening at the base constitutes the umbilicus . The umbilicus varies greatly in size, and may be wholly or in part covered by an expansion or callus of
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3192-458: 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
3268-530: 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 often feature on Cyprus taverna menus, in the meze section, under the name karaoloi ( καράολοι ). In Sicily , snails (or babbaluci as they are commonly called in Sicilian ) are
3344-494: 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
3420-412: The first primary, which generally becomes the shoulder angle if angulation occurs. Secondary spirals may appear by intercalation between the primary ones, and generally are absent in the young shell, except in some highly accelerated types. Tertiary spirals are intercalated between the preceding groups in more specialized species. Ribs are regular transverse foldings of the shell, which generally extend from
3496-733: The flatworms in the process and becoming the final hosts of the flatworm. 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 easily suffer moisture loss. Snails are most active at night and after rainfall . During unfavourable conditions, a snail remains inside its shell, usually under rocks or other hiding places, to avoid being discovered by predators . In dry climates, snails naturally congregate near water sources, including artificial sources such as wastewater outlets of air conditioners . Land snails have been eaten for thousands of years, going back at least as far as
3572-444: 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 crawled. Snails (like all molluscs) also have
3648-407: The gastropod shell is the anterior end, nearest to the head of the animal; the apex of the spire is often the posterior end or at least is the dorsal side. Most authors figure the shells with the apex of the spire uppermost. In life, when the soft parts of these snail are retracted, in some groups the aperture of the shell is closed by using a horny or calcareous operculum , a door-like structure which
3724-429: The gastropod shell. Detailed distinction of the shape can be: The most frequently used measurements of a gastropod shell are: the height of the shell, the width of the shell, the height of the aperture and the width of the aperture. The number of whorls is also often used. In this context, the height (or the length) of a shell is its maximum measurement along the central axis. The width (or breadth, or diameter)
3800-529: The genus Polymita , and the indigenous snails of Hawaii . 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
3876-401: The genus Helix are terrestrial rather than freshwater or marine, they have developed a simple lung for respiration. (Most other snails and gastropods have gills , instead.) Oxygen is carried by the blood pigment hemocyanin . Both oxygen and carbon dioxide diffuse in and out of blood through the capillaries . A muscular valve regulates the process of opening and closing the entrance of
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#17327725287023952-414: The inner lip ( Natica ). Many Recent shells, when the animal is alive or the shell is freshly empty, have an uppermost shell layer of horny, smooth, or hairy epidermis or periostracum , a proteinaceous layer which sometimes is thick enough to hide the color markings of the surface of the shell. The periostracum, as well as the coloration, is only rarely preserved in fossil shells. The apertural end of
4028-456: 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). In Greece , snails are popular in the island of Crete , but are also eaten in many parts of
4104-452: The larger species may live over 10 years in the wild. For instance, 10-year old individuals of the Roman snail 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
4180-419: The later ones. When an angulation occurs, the space between it and the suture above it constitutes the area known as the "shoulder" of the shell. The shoulder angle may be smooth or keeled, and may sometimes have nodes or spines. The most simple form of sculpture of the gastropod shell consists of longitudinal ridges, and/or transverse ridges. Primary spirals may appear in regular succession on either side of
4256-425: The lung. When the valve opens, the air can either enter or leave the lung. The valve plays an important role in reducing water loss and preventing drowning. 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
4332-461: The need to break snail shells by simply swallowing the snail whole, shell and all. Some carnivorous species of snails, such as the decollate snail and the rosy wolf snail , also prey on other land snails. Such carnivorous snails are commercially grown and sold to combat pest snail species. Many of these also escape into the wild, where they prey on indigenous snails, such as the Cuban land snails of
4408-401: The predatory caterpillar Hyposmocoma molluscivora . 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
4484-498: The previous condition of an uncoiled limpet -like shell. In large enough quantities, gastropod shells can have enough of an impact on environmental conditions to affect the ability of organic remains in the local environment to fossilize. For example, in the Dinosaur Park Formation , fossil hadrosaur eggshell is rare. This is because the breakdown of tannins from local coniferous vegetation would have caused
4560-490: 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
4636-482: The question is far from settled. The Peruvian clausiliid, Nenia callistoglypta Pilsbry (1949, pp. 216–217), also has been described as being an amphidromine species. The genetics of reverse coiling in a rare dextral mutant of another clausiliid, Alinda biplicata (Montagu), has been studied by Degner (1952). The mechanism is the same as in Radix peregra (Müller), with the direction of coiling determined by
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#17327725287024712-411: The reduction of the shell is associated with a predatory way of feeding. Some taxa lost the coiling of their shell during evolution. According to Dollo's law , it is not possible to regain the coiling of the shell after it is lost. Despite that, there are few genera in the family Calyptraeidae that changed their developmental timing ( heterochrony ) and gained back ( re-evolution ) a coiled shell from
4788-499: The shell gradually increase in size. Normally the whorls are circular or elliptical in section. The spire can be high or low, broad or slender, according to the way the coils of the shell are arranged, and the apical angle of the shell varies accordingly. The whorls sometimes rest loosely upon one another (as in Epitonium scalare ). They also can overlap the earlier whorls such that the earlier whorls may be largely or wholly covered by
4864-485: 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. 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
4940-410: The shell may be simple or variously modified. An outer and an inner (columellar) lip are generally recognized. These may be continuous with each other, or may be divided by an anterior notch. This, in some types ( Fusinus , etc.) it is drawn out into an anterior siphonal canal , of greater or lesser length. An upper or posterior notch is present in certain taxa, and this may result in the formation of
5016-408: The shell of the latter may exceed 6 cm. At the other end of the size spectrum is Angustopila psammion , a species with shell diameter of 0.60-0.68 mm. 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
5092-420: 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 reproducing. A snail's shell forms a logarithmic spiral . Most snail shells are right-handed or dextral in coiling, meaning that if
5168-573: The snails should be fed flour and offered water for at least a week. This process is thought to cleanse the snails. 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
5244-467: The surface of the shell (see Platyceras ). When a row of spines is formed at the edge or outer lip of the shell during a resting period, this feature sometimes remains behind as a varix as in ( Murex ) and many of the Ranellidae . Varices may also be formed by simple expansion of the outer lip, and a subsequent resumption of growth from the base of the expansion. The aperture or peristome of
5320-455: The suture to suture. They are usually spaced uniformly and crossed by the spirals. In specialized types, when a shoulder angle is formed, they become concentrated as nodes upon this angle, disappearing from the shoulder above and the body below. Spines may replace the nodes in later stages. They form as notches in the margin of the shell and are subsequently abandoned, often remaining open in front. Irregular spines may also arise on various parts of
5396-472: The table but are not thoroughly cooked, can harbor a parasite ( Angiostrongylus cantonensis ) that can cause a rare kind of meningitis . The process of snail farming is called heliciculture . The establishment of snail farms outside of Europe has introduced several species to North America, South America, and Africa, where some escapees have established themselves as invasive species . In parts of West Africa , specifically Ghana , snails are served as
5472-410: The width of the eyes. The second (lower) set of tentacles act as olfactory organs. Both sets of tentacles are retractable in land snails . 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,
5548-480: 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 . They may have a specialized crop of symbiotic bacteria that aid in digestion, especially with
5624-463: The young emerge. Snails may lay eggs as often as once a month. There have been hybridizations of snail species; although these do not occur commonly in the wild, in captivity they can be coaxed into doing so. Parthenogenesis has been reported only in one species of slug, but many species can self-fertilise. C. obtusus is a prominent endemic snail species of the Eastern Alps . There
5700-437: Was introduced in the 19th century by French immigrant glass workers. "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. 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
5776-593: Was marine). The majority of land snails are pulmonates that have a lung and breathe air. Most of the non-pulmonate land snails belong to lineages in the Caenogastropoda , and tend to have a gill and an operculum . The largest clade of land snails is the Cyclophoroidea , with more than 7,000 species. Many of these operculate land snails live in habitats or microhabitats that are sometimes (or often) damp or wet, such as in moss . Land snails have
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