A snail is a mollusc, that is, an animal with a soft body usually covered with a coiled shell. It creeps along the ground using a strong, muscular organ called a foot. In fact, snails and slugs are known as gastropods, which means ‘stomach foot’. This describes the way in which the body and internal organs of slugs and snails has been twisted back so that the stomach lies above the large fleshy foot of these animals. The head is at one end of this foot.
All gastropods have a well-developed head with eyes and 1-2 pairs of tentacles on their head. There are around 80,000 different kinds of snails and they are found everywhere on earth, on land, in the sea and in freshwater. Depending on the species, snails can live 5 – 25 years.
Land snails are found in damp, shady places, near ponds and rivers and in forests. Though they usually live on the ground, in the tropics, land snails are found on trees. They use lungs to breathe.
There are 5000 kinds of freshwater snails which inhabit rivers, ponds, lakes and hot springs. Some have lungs, while others have gills. One species is so adaptable that it has been found in mountain lakes at a height of 5000 metres in the Himalayas!
Marine or sea snails form the largest group, with 55,000 kinds. Some live along the seashore, some on the deep ocean floor. Collectors prize the shells of sea snails and the tropical tree snails of Hawaii. They come in iridescent colours, intricate designs and unusual shapes. Sea snails are also harvested for the luminescent mother-of-pearl that coats the inside of their shells.
Snails move, well, at a snail’s pace! Common garden snails (Helix aspersa) have a top speed of 45 metres (50 yards) per hour, making the snail one of the slowest creatures on Earth. As they move, they leave a trail of sticky, silvery slime. This not only serves to attract mates, but also to protect the snail. The slime is so effective, that a snail moving along a razor’s edge will not cut itself! In dry weather, the snail seals itself inside the shell and plugs the opening with dried slime. It remains this way till the rains come. It is a kind of summer hibernation, called aestivation.
Like earthworms, snails are hermaphrodites — they are both male and female. When two snails do happen to meet in the mating season, they go through a measured ‘dance’. Among banded snails, each snail harpoons the other with a small ‘love dart’ made of calcium to stimulate the other to produce sperm. Then, after fertilisation, each goes its own way to lay eggs!
One of the most venomous, and coveted, sea animals in the world is the cone shell snail. The snail has sharp teeth that inject a paralysing poison. It is so toxic that a man can die within a few hours. But its shell is covered with such beautiful markings that collectors are willing to pay more than £500 for a single good specimen!
The common garden snail is regarded as an agricultural and garden pest as it eats the leaves and stems of crops. The snail is a delicacy in French cuisine and is called escargot. It is also fried and eaten in many other countries across the world.
This species is considered an agricultural and garden pest as it eats the leaves and stems of crops. Being herbivorous, it consumes many types of plant matter. It finds its food in fruit trees, herbs, cereals, flowers and the bark of trees, but occasionally eats decomposing organic matter, either vegetable or animal. Garden snails are a food source for some animals like lizards, frogs, and worms. Predatory insects and other species of snails will also eat garden snails. Some birds too, especially ducks gobble them up.
Did you know?
The eggs of the common garden snail contain a chemical that is used to determine blood groups.
Normally, this chemical is extracted from human blood, but it takes blood from five donors to provide as much as is contained in a single snail’s egg!
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