- A more detailed account is at Gastropoda
|A grapewine snail (Helix pomatia)|
Usually, by 'snail' people mean the snails on land. Land snails usually have lungs, and are in the order Pulmonata. Aquatic snails are in other orders, and usually have gills. Close relatives of the snails are the slugs, which are basically snails without shells. Both slugs and snails are numerous and successful on land. Most land snails and slugs are herbivorous. Aquatic snails and slugs are usually omnivores or predatory carnivores.
The biggest snail is the giant African snail. It is 35 cm long. The fastest snail is the Helis aspersa. It can reach speeds up to 0.03 mph.
Snails are invertebrates, which are animals with no backbones. The shell on the snail helps protect it, and also reduces the loss of water by evaporation. Shells are many different shapes, sizes, and colours. Snails do not breathe through their mouths, instead they have a breathing hole under their shells.
A snails "foot" is a muscle which allows it to move slowly across the ground. The foot puts out ('exudes') slime, which eases the snail's movement, leaving a trail. Snails can absorb mineral nutrients through their foot by simply sitting on a rock containing it.
The head is attached to the foot. The mouth is like a cheese grater. It is called a radula. It is used for cutting food. On the radula there are little teeth. On the head there are 15 mm stalks. On the end of the stalks are snail’s eyes, though they do not see very well.
Snails are found all over the world. Generally speaking, land snails live on damp habitats. They live in caves and dark places. Snails can be found in dark places such as in a garden under plants. Some species live in cold places like the Arctic, and a few are found in warm places like beaches and deserts.
Some snails are aquatic, and live in water. They live in the sea, fish tanks, rivers and oceans. They don’t swim in the water, but stick to rocks.
Snails eat a lot of vegetables such as lettuce, cucumber, and carrots. Snails also eat fruit like apples. Snails use their radula to cut food. The radula is a hard, rough plate in the mouth. Radula teeth are like little pieces of sandpaper. They are good for cutting up plants and if the snail eats meat they are good for tearing the meat apart. Radula teeth look like little fangs.
Many animals eat snails. Fireflies, snakes, beetles, fish, insects, turtles, and people all eat snails too. To defend themselves, snails pull back into their shells.
Slugs evolved from snails which reduced, and finally lost, their shells. They live in similar habitats.
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