Although some earthworms can grow up to 30 centimetres long, most are between 10 and 15 centimetres, with a long, cylindrical body composed of numerous segments. They are violet-pink in colour, with an orange-red saddle between the 32nd and 37th segments.
The earthworm inhabits wet soils rich in humus (organic substances) and is found in most of Europe.
The earthworm lives in the soil, coming to the surface only during the night or heavy rain because of the lack of oxygen (it breathes mostly through its skin). In dry conditions it either goes deeper into the soil or joins a number of other worms who gather together to preserve the moisture they need. It feeds on leaves, grass, and semi-rotten plant waste collected on the surface. It swallows soil as well as food and consumes the organic substances in it. The burrows of earthworms play a major role in aerating and draining the soil.