The reddish-brown body of the earthworm is built like two tubes, one inside the other. The inner one is the digestive tube and the outer one is the body wall. Earthworms do not have eyes or ears, but they have a mouth and are sensitive to heat, light, and touch. A worm crawls by lengthening its front part and pushing through the soil, then pulling the hind part up. A worm's body wall has two kinds of muscles that it uses to crawl.
Circular muscles surround the worm's body and can make the body shrink or spread out.
Longitudinal muscles run the length of the body and can shorten or lengthen the worm. The earthworm has no lungs or gills. It breathes through its thin skin, which is in contact with the air between the particles of soil. If the weather becomes too dry and warm, a worm will die. Earthworms feed on dead plant material that is found in the soil.