Snail
From Freepedia
- Snail also refers to a chess engine; see Snail (chess) as well as a power source for a rotary snowplow.
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Image:Achatina fulica Thailand.jpg
The name snail applies to most members of the molluscan class Gastropoda that have coiled shells. Other gastropods, which lack a conspicuous shell, are commonly called slugs, and are scattered throughout groups that primarily include snails. Snails are found in freshwater, marine, and terrestrial environments. While most people are familiar with only terrestrial snails, the majority of snails are not terrestrial. Snails with lungs belong to the group Pulmonata, while those with gills belong to the Paraphyletic group.
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Physical Characteristics
Image:European brown snail.JPG Image:Gardensnail.jpg Snails move like worms by alternating body contractions with stretching, with a proverbially low speed. They produce mucus in order to aid locomotion by reducing friction. The mucus also reduces the snail's risk of injury and helps keep away potentially dangerous insects like ants. When retracted into their shells, snails cover the entrance with a 'trapdoor' like structure called an operculum.
Snails come in a range of different sizes. The largest land snail is the Giant African Snail (Achatina achatina; Family Achatinidae), which can measure up to 30 cm. Pomacea maculata (Family Ampullariidae), or Giant Apple Snail is the largest freshwater snail, with its size reaching 15 cm diameter and over 600 g weight. The biggest of all snails is Syrinx aruanus, a marine species living in Australia. Shell lengths up to 1 m have been reported.
Habitat
As one of the largest classes of animals, snails can be found throughout the world. They are found in freshwater, marine, and terrestrial environments. The majority of the world's snails live in the oceans and new species are being discovered regularly. Terrestrial snails prefer damp areas around vegetation which they can use for cover during the day.
Diet
A snail's diet varies by species. Terrestrial snails such as garden snails generally eat young plant shoots or bark, or decaying vegetative matter. Carnivorous snails, such as the Decollate Snail feed on other snails. Snails eat by using their radula, or scraping tongue, to shear their food.
Reproduction
Some snails are hermaphrodites, producing both spermatozoa and ova. Others, such as Apple Snails, are either male or female. Prolific breeders, snails in pairs inseminate each other to internally fertilize their ova. 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. After 2 to 4 weeks of favorable weather, these eggs hatch and the young emerge. Snails may lay eggs as often as once a month.
Predators
Snails have many natural predators, including ground beetles, snakes, toads, turtles, and birds like chickens, ducks and geese, and even a predatory caterpillar.
Snails are widely used as human food (often known as escargots) in Europe, Asia and [Africa]]. Two species commonly eaten in Europe are the Burgundy snail (Helix pomatia) and the brown garden snail (Helix aspersa) also known as the European brown snail.
Lifespan
The lifespan of snails varies from species to species. In the wild, Achatinidae snails live around 5 to 7 years and Helix snails live about 2 to 3 years. Aquatic Apple Snails live only a year or so. Most deaths are due to predators or parasites.
Trivia
In addition to being a common metaphor for a slow person, the snail is traditionally considered in many countries to predict the weather with its behaviour. In Finland this has led to a rhyme, where the snail is asked to show his tentacles. If the snail wear his "horns" high, tomorrow will be fine weather.
Snail is also the name of the Ultimate Frisbee team for the State University of New York College at Geneseo.
A Snail can withstand the force of air at over 75Mph whilst still being able to move accross the bonnet of the moving vehicle at the same time.
External links
- Snail eating
- Brown garden snail
- Molluscs
- Kiddyhouse.com page on snails
- Snails as pets
- The trail of the snail
- [1]
- Snail Obsession
- world of snails
