The reddish-gray-colored common earthworm, often called a night crawler in the United States, is familiar to anyone with a fishing rod or a garden. They are indigenous to Europe, but are now abundant in North America and western Asia.
Typically only a few inches in length, some members of this species have been known to grow to a serpentine 14 inches. Earthworms’ bodies are made up of ring-like segments called annuli. These segments are covered in setae, or small bristles, which the worm uses to move and burrow.
Night crawlers are so named because they are usually seen feeding above ground at night. They burrow during the day—typically keeping close to the surface—capable of digging down as deep as 6.5 feet.