Our Privacy/Cookie Policy contains detailed information about the types of cookies & related technology on our site, and some ways to opt out. By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use.


Nightcrawler Facts

i Creatas/Creatas/Getty Images

If you fish, there is no doubt you have handled a slimy nightcrawler worm. There are several species of nightcrawlers, such as the Canadian and European nightcrawlers. In the United States, the common earthworm is often called a nightcrawler. One main difference, however, is that true nightcrawlers generally live deeper in the ground.

Nightcrawler Characteristics

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.

Different Species

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.

Dinner Time

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.

Male or Female?

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.