They tunnel deeper into the ground. Earthworms need moisture to survive, so they spend most of their lives underground, in the top three feet of soil. At those depths, they usually have the moisture they need as well as leaves and other dead plant material to eat. But if the soil becomes too dry, they will dig down in search of moisture. Some earthworm burrows can go as deep as six feet below the surface.
Photo by: blickwinkel/Alamy
