Nightcrawler Facts

Nightcrawlers are generally red, brown or gray in color. The head is generally darker than the “flat” tail of nightcrawlers. Their long bodies are covered with annuli, or round segments. Setae, or small bristles, cover the segments of the body and help the nightcrawler move and dig into the ground, reaching depths of 6 feet. Mucus covers the nightcrawler's skin and allows dissolved oxygen to enter its bloodstream.

European nightcrawlers are the smallest of the three common species. They generally only grow reach about 2 inches in length when fully grown. The Canadian and U.S. nightcrawlers grow much larger, reaching up to 14 inches. The nightcrawler’s more common size, however, is between 7 and 8 inches. The larger species are often found at the end of a fishing line, since they are the preferred feast for bass fish. Turtles and birds also like to feast on the juicy nightcrawler.

Nighcrawlers get their name from their nighttime feeding schedule. They often burrow below the surface of the ground during the day and come out at night. As they burrow into the ground the feed off of organic matter, such as leaves and dead grass, making them herbivores. At night, they grab their food from the surface and drag it underground when feeding. Where large groups live, it is common to hear them rustling leaves at night during feeding.

Nightcrawlers are hermaphrodites, meaning they have both male and female reproductive organs. Fertilization occurs outside of the worm’s body in a tiny cocoon. Since nightcrawlers are not self-fertilizing, each worm deposits sperm into the other worms' eggs when mating, creating two separate sets of fertilized eggs. The fertilized eggs are then dispersed into the cocoon. The cocoon lays dormant and, in two to four weeks, one to two baby worms break free. Each worm produces around 10 to 15 babies per year. In perfect conditions with no predators present, the worms may live between 8 and 10 years.