About Nightcrawlers

Nightcrawlers, another name for the common earthworm, most often can be found on a fishing hook or crawling through the soil on a rainy day. More than 1,000 different types of earthworms exist worldwide, some growing to 3 feet long. However most common earthworms, including those found in North America, are just a few inches in length.

History

According to the Fairfax County Public Schools ecology study, European settlers brought nightcrawlers to North America (See Reference 1). Native earthworms disappeared long ago, it is believed. Nightcrawlers claim the title of largest of the North American earthworms and may grow to 8 inches long.

Geography

Nightcrawlers live in soil where they dig long tunnels while swallowing and digesting dead organic material. Common nightcrawler predators include frogs, turtles and birds. You can easily find nightcrawlers along moist river and stream banks, in private lawns and in public gardens and parks. Nightcrawler burrows may be 6 to 8 feet deep. According to the Florida State University website, up to 70 nightcrawlers may be present in a square meter of soil (See Reference 2).

Features

Nightcrawlers may live up to 6 years, according to the Florida State University science website (See Reference 2). They produce an average of 38 cocoons annually, inside of which is one egg. Nightcrawlers live in large colonies that may rapidly grow by several meters a year.

Benefits

Nightcrawlers perform beneficial tasks such as decomposition and aeration of the soil. They break down and assist in the decay of dead plant material that helps to improve the topsoil. As they move through the soil, they mix nutrients and achieve many tunnels through which air, water and nutrients may travel. In addition, as they move through the layers of soil, from deeper soil toward the topsoil they bring minerals and nutrients from the richer bottom soil to the topsoil.

Considerations

Though very simple creatures, nightcrawlers share some interesting features. Nightcrawlers can regenerate a body part that is cut off. They breathe through their skin, so they must constantly attempt to stay moist, which aides breathing. When nightcrawlers come out on rainy days, they seek new homes and extra moisture rather than the assumed flooding out of their tunnels. According to the Montana State University site, nightcrawlers can create up to 1200 tunnels per square yard of soil (See Reference 3).