Earthworms belong to the Phylum Annalid, along with leaches, and to the class Oligochaeta. They play an important role in improving the soil. By their burrowing habits, they allow more air and water to reach deeper into the ground. They also feed on the decaying material in and on the ground and their castings enrich the soil. They are also an important food source for many animals and birds.
The Common Earthworm grows to be about 10 inches long and about 1/2 inch in diameter, and are usually reddish in color. Their bodies are segmented and each segment has 4 stiff bristles called setae, which they use to anchor that segment when they move, so they can drag the rest of their body forward, or back as the case may be.