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{{Short description|Shelled gastropod}}
{{Other uses|Snail (disambiguation)}}
{{About||sea snails|Sea snail|land snails|Land snail|}}

{{Paraphyletic group
| name = Snails
| image = Snail.jpg
| image_caption = ''[[Helix pomatia]]'', a species of land snail
| auto = yes
| taxon = Gastropoda
}}
[[File:Epiphragma einer Weinbergschnecke.JPG|thumb|''[[Helix pomatia]]'' sealed in its shell with a [[calcareous]] [[epiphragm]]]]

A '''snail''' is a shelled [[gastropod]]. The name is most often applied to [[land snails]], [[terrestrial molluscs|terrestrial]] [[pulmonate]] [[gastropod]] [[mollusc]]s. However, the common name ''snail'' is also used for most of the members of the molluscan class [[Gastropoda]] that have a coiled [[gastropod shell|shell]] that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of [[sea snail]]s and [[freshwater snail]]s. Gastropods that naturally lack a [[gastropod shell|shell]], or have only an internal shell, are mostly called ''[[slug]]s'', and land snails that have only a very small shell (that they cannot retract into) are often called ''[[semi-slug]]s''.

Snails have considerable human relevance, including as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewelry.<ref>{{Cite web|url=https://favpng.com/png_view/snail-jewellery-brooch-earring-diamond-pin-png/Y7N2yJ0j|title=Snails used in Jewellery}}</ref> The snail has also had some cultural significance, tending to be associated with lethargy. The snail has also been used as a [[figure of speech]] in reference to slow-moving things. The snail is the same or similar shape as the [[cochlea]].<ref>{{Cite magazine|url=https://physics.aps.org/story/v17/st8|title=Why the inner ear is snail shaped|magazine=Physical Review Focus|date=3 March 2006|volume=17|last1=Monroe|first1=Don|page=8}}</ref>

==Overview==
Snails that [[respiration (physiology)|respire]] using a [[lung]] belong to the group [[Pulmonata]]. As traditionally defined, the Pulmonata were found to be [[polyphyletic]] in a molecular study per Jörger ''et al.'', dating from 2010.<ref name="Jörger 2010">{{cite journal|last=Jörger|first=Katharina M|author2=Stöger, Isabella |author3=Kano, Yasunori |author4=Fukuda, Hiroshi |author5=Knebelsberger, Thomas |author6= Schrödl, Michael |title=On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia|journal=BMC Evolutionary Biology|year=2010|volume=10|issue=1|pages=323|doi=10.1186/1471-2148-10-323|pmid=20973994|pmc=3087543 |doi-access=free }}</ref> But snails with [[gill]]s also form a [[polyphyletic]] group; in other words, snails with lungs and snails with gills form a number of [[Taxonomy (biology)|taxonomic]] groups that are not necessarily more closely related to each other than they are related to some other groups.

Both snails that have lungs and snails that have gills have diversified so widely over geological time that a few species with gills can be found on land and numerous species with lungs can be found in freshwater. Even a few marine species have lungs.

Snails can be found in a very wide range of environments, including [[ditch]]es, [[desert]]s, and the [[abyssal zone|abyssal]] depths of the sea. Although [[terrestrial ecoregion|land]] snails may be more familiar to laymen, [[marine biology|marine]] snails constitute the majority of snail species, and have much greater diversity and a greater [[biomass (ecology)|biomass]]. Numerous kinds of snail can also be found in [[freshwater snail|fresh water]].

Most snails have thousands of microscopic tooth-like structures located on a banded ribbon-like tongue called a [[radula]]. The radula works like a file, ripping food into small pieces. Many snails are [[herbivore|herbivorous]], eating plants or rasping algae from surfaces with their radulae, though a few land species and many marine species are [[omnivore]]s or [[predation|predatory]] [[carnivore]]s. Snails cannot absorb colored pigments when eating paper or cardboard so their feces are also colored.<ref>{{cite web|url=https://www.dezeen.com/2013/11/26/tiles-made-from-snail-poo-by-lieske-schreuder/|title=Floor tiles made of coloured snail poo by Lieske Schreuder - design|date=26 November 2013|access-date=29 March 2018}}</ref>

Several species of the genus ''[[Achatina]]'' and related genera are known as giant African land snails; some grow to {{Convert|15|in|cm|abbr=on}} from snout to tail, and weigh {{convert|1|kg|0|abbr=on}}.<ref name="Fredericks2010">{{cite book |last=Fredericks |first=Anthony D. |year=2010 |title=How Long Things Live & How They Live As Long As They Do |publisher=Stackpole Books |isbn=9780811736220 |page=[https://archive.org/details/howlongthingsliv0000fred/page/73 73] |url=https://archive.org/details/howlongthingsliv0000fred |url-access=registration |access-date=19 June 2012}}</ref> The largest living species of sea snail is ''[[Syrinx aruanus]]''; its shell can measure up to {{convert|90|cm|abbr=on}} in length, and the whole animal with the shell can weigh up to {{convert|18|kg|abbr=on}}. Recently, the smallest land snails, ''[[Angustopila dominikae]],'' have been discovered in China, and measure 0.86mm long.<ref>{{Cite web|last=Hogenboom|first=Melissa|date=27 July 2020|title=The world's smallest snail has been discovered.|url=http://www.bbc.com/earth/story/20150928-the-worlds-smallest-snail-discovered|website=BBC}}</ref>

The snail ''[[Lymnaea]]'' makes decisions by using only two types of neurons: one deciding whether the snail is hungry, and the other deciding whether there is food in the vicinity.<ref>{{cite journal |last1=Crossley |first1=Michael |last2=Staras |first2=Kevin |last3=Kemenes |first3=György |date=3 June 2016 |title=A two-neuron system for adaptive goal-directed decision-making in ''Lymnaea'' |journal=Nature Communications |volume=7 |doi=10.1038/ncomms11793 |pmid=27257106 |pmc=4895806 |page=11793|bibcode=2016NatCo...711793C }}</ref>

The largest known land gastropod is the African giant snail ''Achatina achatina'', the largest recorded specimen of which measured {{Convert|39.3|cm|in}} from snout to tail when fully extended, with a shell length of {{Convert|27.3|cm|in|abbr=on}} in December 1978. It weighed exactly 900 g (2 lb). Named Gee Geronimo, this snail was owned by Christopher Hudson (1955–79) of Hove, East Sussex, UK, and was collected in Sierra Leone in June 1976.<ref>{{Cite web|website=Guinness World Records|title=Largest Snail|url=http://www.guinnessworldrecords.com/explore-records/animals?page=2|access-date=17 December 2016}}</ref>

Snails are [[Protostome|protostomes]]. That means during development, in the [[gastrulation]] phase, the blastopore forms the mouth first. Cleavage in snails is spiral holoblastic patterning. In spiral holoblastic cleavage, the cleavage plane rotates each division and the cell divisions are complete. Snails do not undergo metamorphosis after hatching. Snails hatch in the form of small adults. The only additional development they will undergo is to consume calcium to strengthen their shell. Snails can be male, female, [[Hermaphrodite|hermaphroditic]], or [[Parthenogenesis|parthenogenetic]] so there are many different systems of sexual determination.

==Diet==
[[File:Salyangozlar (Kadıköy - Hasanpaşa).jpg|thumb| Snails that live in nature but are fed by humans. (Kadıköy, Istanbul - Turkey)]]
Snails' eating habits vary widely, with some being generalists and some being specialist feeders.<ref name="NHMLAC">{{cite web |url=https://nhm.org/stories/microscopic-look-snail-jaws|title=A Microscopic Look at Snail Jaws |last=Vendetti |first=Jann |website=nhm.org |publisher= Natural History Museum Los Angeles County |access-date=2022-01-05}}</ref> Snails feed at night.<ref name="google.co.in">{{cite book |title=Texas Bug Book: The Good, the Bad, and the Ugly - Page 144 |date = September 2005|publisher = University of Texas Press|isbn = 9780292709379| url=https://books.google.com/books?id=3V_w-6tA8hYC&dq=Snail+feeds+on&pg=PA144 }}</ref> They feed primarily on decaying organic matter.<ref name="google.co.in"/> Their diet also includes fungi, lichens, green foliage, worms, centipedes, insects, animal feces, carrion, and other slugs.<ref name="google.co.in"/> Some snails feed on other snails too.<ref name="google.co.in"/>

==Types of snails by habitat==
{{Main article|Land snail|Freshwater snail|Sea snail}}

==Slugs==
{{Main article|Slug}}
{{One source|section
| date = March 2018
}}
[[File:Slug 02.jpg|thumb|Slug]]
[[Gastropods]] that lack a conspicuous shell are commonly called [[slug]]s rather than snails.<ref>{{cite web|url=https://www.diffen.com/difference/Slug_vs_Snail|title=Slug vs Snail - Difference and Comparison - Diffen|access-date=29 March 2018}}</ref> Some species of slug have a maroon-brown shell, some have only an internal [[Vestigiality|vestige]] that serves mainly as a calcium lactate repository, and others have some to no shell at all. Other than that there is little [[Morphology (biology)|morphological]] difference between slugs and snails. There are however important differences in habitats and behavior.

A shell-less animal is much more maneuverable and compressible, so even quite large land slugs can take advantage of habitats or retreats with very little space, retreats that would be inaccessible to a similar-sized snail. Slugs squeeze themselves into confined spaces such as under loose bark on trees or under stone slabs, logs or wooden boards lying on the ground. In such retreats they are in less danger from either predators or desiccation. Those are often suitable places for laying their eggs.

Slugs as a group are far from [[Monophyly|monophyletic]]; scientifically speaking "slug" is a term of convenience with little taxonomic significance. The reduction or loss of the shell has evolved many times independently within several very different lineages of gastropods. The various taxa of land and sea gastropods with slug morphology occur within numerous higher taxonomic groups of shelled species; such independent slug taxa are not in general closely related to one another.

==Human relevance==
{{More citations needed section|date=March 2018}}
[[File:Snail-wiki-120-Zachi-Evenor.jpg|thumb|''[[Cornu aspersum]]'' – garden snail]]
Land snails are known as an agricultural and garden pest but some species are an edible delicacy and occasionally household [[pet]]s. In addition, their mucus can also be used for skin care products.<ref>{{Cite web |last=Howley |first=Elaine |date=18 July 2022 |title=Snail Mucin for Skin Care: Products and Uses |url=https://health.usnews.com/wellness/articles/snail-mucin-for-skin-care |url-status=live |archive-url=https://web.archive.org/web/20230718220458/https://health.usnews.com/wellness/articles/snail-mucin-for-skin-care |archive-date=18 July 2023 |access-date=29 July 2023 |website=U.S. News}}</ref>

===In agriculture===
There are a variety of snail-control measures that gardeners and farmers use in an attempt to reduce damage to valuable plants. Traditional pesticides are still used, as are many less toxic control options such as concentrated [[garlic]] or [[Artemisia (plant)|wormwood]] solutions. [[Copper]] metal is also a snail repellent, and thus a copper band around the trunk of a tree will prevent snails from climbing up and reaching the foliage and fruit. A layer of a dry, finely ground, and scratchy substance such as [[diatomaceous earth]] can also deter snails.<ref>Sanders, April. [http://homeguides.sfgate.com/egg-shells-stop-snails-eating-plants-87576.html "Do Egg Shells Help Stop Snails From Eating Plants?"] Home Guides | [[SF Gate]]. Accessed 01 July 2019.</ref>

The [[decollate snail]] (''Rumina decollata'') will capture and eat garden snails, and because of this it has sometimes been introduced as a [[biological pest control]] agent. However, this is not without problems, as the decollate snail is just as likely to attack and devour other gastropods that may represent a valuable part of the native fauna of the region.

===As food===
{{Main article|Heliciculture}}

[[File:Cooked snails.JPG|thumb|right|[[Escargot|French cooked snails]]]]
In [[French cuisine]], edible snails are served for instance in ''[[Escargot]] à la [[Burgundy|Bourguignonne]]''. The practice of rearing snails for food is known as [[heliciculture]]. For purposes of cultivation, the snails are kept in a dark place in a wired cage with dry straw or dry wood. [[Coppiced]] wine-grape vines are often used for this purpose. During the rainy period, the snails come out of [[Land snail#Hibernation and estivation|hibernation]] and release most of their mucus onto the dry wood/straw. The snails are then prepared for cooking. Their texture when cooked is slightly chewy and tender.

As well as being relished as gourmet food, several species of land snails provide an easily harvested source of [[Protein (nutrient)|protein]] to many people in poor communities around the world. Many land snails are valuable because they can feed on a wide range of agricultural wastes, such as shed leaves in [[banana plantations]]. In some countries, [[giant African land snail]]s are produced commercially for food.

Land snails, freshwater snails and sea snails are all eaten in many countries. In certain parts of the world snails are fried. For example, in [[Indonesia]], they are fried as [[satay]], a dish known as ''[[sate kakul]]''. The eggs of certain snail species are eaten in a fashion similar to the way [[caviar]] is eaten.<ref>{{cite news | url=https://www.reuters.com/article/us-france-snails-idUSL2055417620071220 | title=The height of slow-food, France serves snail caviar | newspaper=Reuters | date=20 December 2007 }}</ref>

In [[Bulgaria]], snails are traditionally cooked in an oven with rice or fried in a pan with vegetable oil and red paprika powder. Before they are used for those dishes, however, they are thoroughly boiled in hot water (for up to 90 minutes) and manually extracted from their shells. The two species most commonly used for food in the country are ''[[Helix lucorum]]'' and ''[[Helix pomatia]]''.{{citation needed|date=January 2020}}

====Famine food====
Snails and slug species that are not normally eaten in certain areas have occasionally been used as [[famine food]] in historical times. A history of Scotland written in the 1800s recounts a description of various snails and their use as food items in times of plague.<ref>{{cite book |last=Chambers |first=Robert |author-link=Robert Chambers (publisher born 1802) |year=1858|title=Domestic annals of Scotland, from the reformation to the revolution |publisher=[[Chambers Harrap|W. & R. Chambers]] |url=https://archive.org/details/domesticannalsof02chamiala}} (Also quoted [http://www.electricscotland.com/history/domestic/vol2ch2c.htm here].</ref>

==Parasitic diseases==
Snails can also be associated with parasitic diseases such as [[schistosomiasis]], [[angiostrongyliasis]], [[fasciolopsiasis]], [[opisthorchiasis]], [[fascioliasis]], [[paragonimiasis]] and [[clonorchiasis]], which can be transmitted to humans.

==Cultural depictions==
[[File:Mochesnail.jpg|thumb|Land snails (''[[Scutalus]]'' sp.) on a [[Moche (culture)|Moche]] pot, 200 AD, [[Larco Museum|Larco Museum Collection]], Lima, Peru]]

=== Symbolism ===
Because of its slowness, the snail has traditionally been seen as a symbol of laziness. In Christian culture, it has been used as a symbol of the [[Seven deadly sins|deadly sin]] of [[Sloth (deadly sin)|sloth]].<ref name="deVries76">{{cite book |last=de Vries |first=Ad |year=1976 |title=Dictionary of Symbols and Imagery |publisher=North-Holland Publishing Company |location=Amsterdam |isbn=978-0-7204-8021-4 |page=[https://archive.org/details/dictionaryofsymb0000vrie/page/430 430] |url=https://archive.org/details/dictionaryofsymb0000vrie/page/430 }}</ref><ref>{{cite book |last=Tresidder |first=Jack |year=2006 |title=Symbols and Their Meanings |publisher=Barnes & Noble |location=New York |isbn=978-0-7607-8164-7 |page=41 |url=https://books.google.com/books?id=tlVsHBc443gC&q=The+snail+was+also+a+Christian+emblem+of+sloth.+...}}</ref> [[Psalms]] {{bibleverse-nb||Psalms|58:8|!}} uses [[snail slime]] as a [[metaphor]]ical punishment. In [[Mayan mythology]], the snail is associated with sexual desire, being [[personification|personified]] by the god [[Uayeb]].<ref>Susan Milbrath, Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars, University of Texas Press, 01/01/2010</ref>

=== Divination and other religious uses ===

Snails were widely noted and used in [[divination]].<ref name="deVries76"/> The [[Greeks|Greek]] poet [[Hesiod]] wrote that snails signified the time to harvest by climbing the stalks, while the [[Aztec mythology|Aztec]] moon god [[Tecciztecatl]] bore a snail shell on his back. This symbolised rebirth; the snail's penchant for appearing and disappearing was analogised with the [[moon]].<ref name="Cooper92">{{cite book |last=Cooper |first=J. C. |year=1992 |title=Symbolic and Mythological Animals |publisher=Aquarian Press |location=London |isbn=978-1-85538-118-6 |page=213}}</ref>

=== Love darts and Cupid ===
[[File:Monachoides vicinus dart lateral.jpg|thumb|240px|The use of [[love dart]]s by the land snail ''[[Monachoides vicinus]]'' is a form of [[sexual selection]]]]

Professor Ronald Chase of [[McGill University]] in [[Montreal]] has suggested the ancient myth of [[Cupid]]'s arrows might be based on early observations of the [[love dart]] behavior of the land snail species ''Cornu aspersum''.<ref>{{cite web |last=Mayell |first=Hillary |date=February 13, 2004 |title=Lovebirds and Love Darts: The Wild World of Mating |website=news.national-geographic.com |publisher=[[National Geographic Society]] |url=http://news.nationalgeographic.com/news/2004/02/0212_040213_lovebirds_2.html |access-date=2010-02-21}}</ref>

=== Metaphor ===
In contemporary speech, the expression "a snail's pace" is often used to describe a slow, inefficient process. The phrase "[[snail mail]]" is used to mean regular postal service delivery of paper messages as opposed to the delivery of [[email]], which can be virtually instantaneous.

In medieval and Renaissance manuscripts snails are depicted as a comic relief due to the similarity between the armour of knights and the shell of snails.<ref>Monge-Nájera, J. (2019). Pulmonate snails as marginalia in medieval and Renaissance manuscripts: a review of hypotheses. Darwin In Memoriam: History of Science. BLOG RPT.https://revistas.ucr.ac.cr/index.php/rbt/article/view/38872</ref>

=== In Indonesian mythology ===
{{main article|Keong Emas}}
[[File:Dewi Sekartaji Keong Emas.JPG|thumb|Dewi Sekartaji as Keong Emas]]

'''Keong Emas''' ([[Javanese language|Javanese]] and [[Indonesian language|Indonesian]] for '''Golden Snail''') is a popular [[Javanese culture|Javanese]] [[folklore]] about a princess magically transformed and contained in a [[Pomacea canaliculata|golden snail]] shell. The folklore is a part of popular Javanese [[Panji (prince)|Panji cycle]] telling the stories about the prince Panji Asmoro Bangun (also known as Raden Inu Kertapati) and his consort, princess Dewi Sekartaji (also known as Dewi Chandra Kirana).

===Textiles===
Certain varieties of snails, notably the family [[Muricidae]], produce a secretion that is a color-fast [[natural dye]]. The ancient [[Tyrian purple]] was made in this way as were other purple and blue dyes.<ref>{{cite journal |last=Ziderman |first=I. I. |year=1986 |title=Purple dye made from shellfish in antiquity |journal=Review of Progress in Coloration |issn=1472-3581 |volume=16 |pages=46–52|doi=10.1111/j.1478-4408.1986.tb03743.x }}</ref><ref>{{cite journal |title=Whelks and purple dye in Anglo-Saxon England |last=Biggam |first=Carole P. |journal=The Archeo+Malacology Group Newsletter |issue=9 |date=March 2006 |url=http://triton.anu.edu.au/MalacGp09.pdf }}</ref><ref>{{cite book |last=Moorey |first=Peter |year=1999 |title=Ancient Mesopotamian Materials and Industries: The Archaeological Evidence |url=https://archive.org/details/ancientmesopotam00moor |url-access=limited |publisher=Eisenbrauns |location=[[Winona Lake, Indiana]] |isbn=978-1-57506-042-2 |page=[https://archive.org/details/ancientmesopotam00moor/page/n81 138]}}</ref> The extreme expense of extracting this secretion is sufficient quantities limited its use to the very wealthy. It is such dyes as these that led to certain shades of purple and blue being associated with royalty and wealth.<ref name="Tyrian Purple">{{cite book |last=Nuttall |first=Zelia |author-link=Zelia Nuttall |editor1-last=Boas |editor1-first=Franz |year=1909 |chapter=A Curious Survival in Mexico of the Use of the Purpura Shell-fish for Dyeing |title=Putnam Anniversary Volume |volume=Anthropological Essays Presented to Fredrick Ward Putnam in Honor of his Seventieth Birthday, by his Friends and Associates |publisher=G. E. Stechert & Co. |location=New York |lccn=10011191 |pages=368–384 |chapter-url=https://archive.org/details/cu31924029880774}}</ref>

== As pets ==
Throughout history, snails have been kept as pets. There are many famous snails such as [[Jeremy (snail)|Lefty]] (Born Jeremy) and within fiction, [[Gary Snail|Gary]] and [[Brian the Snail|Brian the snail]].<ref>{{Cite web|url=https://www.bbc.co.uk/programmes/articles/J1y1vyNcTlCsfp7CmQTz03/seven-of-the-worlds-most-famous-snails|title=BBC Radio 3 – Slow Radio – Seven of the world's most famous snails|website=BBC|language=en-GB|access-date=2020-02-14}}</ref>

==See also==
* [[Gastropod shell]]
* [[Pasilalinic-sympathetic compass]]
* [[Jeremy (snail)]]
* [[Land snail]]
* [[Freshwater snail]]
* [[Sea snail]]

==References==
{{Reflist}}

==Gallery==
<gallery>
File:The snail 1 నత్త.jpg|A snail
File:Snail climbing stone slabs.png|Snail climbing stone slabs at [[Servia, Greece]]. The shell is so heavy that its bottom side becomes visible.
File:SeaSnails.ogv|Snails feeding on the sea floor (50 sec)
File:Snail Melc melc codobelc.ogv|Video of snail after rain (31 sec)
File:Snail moving on ground.webm|Snail moving on a wet ground
File:Snail moving across leaves.webm|Snail moving across leaves.
File:Lumache nei monti Iblei - Pantalica.jpg|Snails in the [[Hyblaean Mountains]].
</gallery>

==External links==

* [http://www.snail-world.com/ Introduction to Snails], Infoqis Publishing, Co.

{{Edible molluscs}}
{{Authority control}}

[[Category:Articles containing video clips]]
[[Category:Mollusc common names]]
[[Category:Gastropods|*]]
[[Category:Paraphyletic groups]]

Snail - Revision history

Ajay Kumar: Created a new article