Slugs are similar to snails but have only a tiny internal shell. Slugs and snails are gastropods, meaning foot-eaters. They have rasps on their mouths which rub against the food that they are crawling over. As a result, they eat a long trail, leaving a kind of slot in a leaf to show where they have been.

Slugs and snails have two pairs of feelers on their head. The upper pair is light sensing and has eyespots at the ends, while the lower pair gives the sense of smell. Both pairs are retractable, and can be regrown if lost.

A snail moves by squeezing its muscular foot in a kind of wave. At the same time, it gives out a layer of mucus that it travels on. This is designed to prevent damage to the foot tissues which contain the mouth.

Snails' bodies are made up mostly of water, and their soft tissues easily dry out. This is why land snail hide away during warm, sunny days inside their shells, and come out to feed in the evening, especially after rain or when there is dew. Sea snails hide away for the same reason - but they have to do this twice a day, each time the tide goes out.

We often think of snails as pests, but in a natural environment snails play an important role by eating decaying plant material and fungi. Most snails feed on leaves from living plants, lichens, mushrooms, and even dead animals.

Snails are food for reptiles, birds, mammals, frogs and toads. Mammals that eat snails, include foxes, badgers and hedgehogs.