Unusually among animals, land snails produce cellulase, an enzyme that can break down cellulose, says Tony Cook. As such, it is quite common to see them feeding on paper and cardboard, which are both made from cellulose.
All land snails (and slugs) are grazers in a literal sense, rasping particles from the substrate with long, toothed tongues. In the stomach, this fine food is sorted into small digestible and larger indigestible lumps. The bigger items are voided, often as a green string, while the smaller particles pass through the digestive gland, emerging as a black string.
- Do snails and slugs have teeth? From cutting to slicing, why snails and slugs have thousands of deadly teeth
- How do slugs and snails move?
Diet, however, varies greatly, even between closely related groups. Some snails specialise in algae, lichens, detritus or carrion, while others are active carnivores, hunting and eating other snails.
Only a few species, such as the garden snail, would ever lay waste to a horticulturalist's crops.
