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Earthworm Facts & Worksheets

Earthworms are small, soil-dwelling invertebrates and are good biological indicators of soil health.

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Earthworms are small, soil-dwelling invertebrates sensitive to the pH, waterlogging, compaction, rotation, tillage, and organic matter, all of which are good biological indicators of soil health. Earthworms can be found in nearly every type of soil on the planet, as long as the moisture and organic content are adequate.

See the fact file below for more information on Earthworms, or alternatively, you can download our 22-page Earthworm worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

Amazing Earthworm Facts

  • The sun’s ultraviolet radiation is lethal to the thin-skinned earthworm, so they can only be found on the surface in dull, wet weather.
  • Earthworms are hermaphrodites, which means they possess both male and female sex organs. However, they cannot fertilize themselves. To share genetic information, they need to mate with another worm.
  • Earthworms can carry up to 20 eggs in a cocoon that can withstand adverse environmental conditions, but only one worm generally emerges.
  • When an earthworm loses one end of its body, it can grow another, but when it is cut in half, it dies. They don’t split into two new worms, contrary to what some believe.
  • Earthworms, unlike many other animals, eat the soil. They crunch it up in their muscular stomach, digest what they can (organic matter mixed with mineral fragments), and then eject the rest.
  • Earthworm poop is called ‘cast.’

Anatomy of the Earthworm

  • These are some of the internal parts that can be found in an earthworm:
  • The mouth cavity is the opening for the digestive tract that helps obtain nutrients from the soil.
  • The pharynx is the muscular throat that pushes food down into the esophagus.
  • The esophagus is the tube that connects the pharynx to the crop of an earthworm.
  • The crop is where the food is stored and softened.
  • The gizzard serves as the stomach of an earthworm.
  • The ventral nerve cord is a group of nerves in the abdomen.
  • The seminal receptacle is a pocket containing semen.
  • The nephridium serves as a kidney-like organ.
  • The dorsal blood vessel is located at the back of the body.
  • The seminal vesicles are small hollow organs that carry sperm.
  • The lateral heart is a blood-pumping system. An earthworm has five aortic arches that together function as a heart and circulate blood through its body. 
  • The ventral blood vessel is the front blood vessel.
  • The brain is in charge for sending and receiving messages to the nervous system.
  • While these are the external parts that can be seen in an Earthworm:
  • The prostomium is the anterior cephalized first body segment of an annelid worm. It is usually a tiny shelf- or lip-like extension over the dorsal side of the mouth and is located in front of the mouth.
  • Setae are also referred to as chaetae. Chitin, a horny nitrogenous organic substance, is used to make them. There are approximately 80–120 setae on each body segment.
  • Clitellum is a thickened glandular and non-segmented section of the body wall near the head that secretes a viscid sac where eggs are stored.
  • Anus is the one that’s in charge of excreting the castings.

Types of Earthworm

  • Earthworms are divided into three types based on where they live.
  • Epigeic worms, also known as surface dwellers because these worms do not dig burrows and instead live among decaying organic matter on the soil surface, among piles of leaves or in compost heaps. Their name derives from the Greek word epigeic, which means ‘on the earth.’ They’re small, ranging in length from less than an inch to seven inches.
  • Endogeic worms live below ground. Their name derives from the Greek work endogeic, which translates to ‘within the earth.’ They are small, measuring between one and twelve inches in length. They are usually very pale or translucent and colorless, and their muscles are weaker than those of Epigeic worms, so they move more slowly.
  • Anecic worms live below ground but they come above ground for food sources. Their name derives from the Greek word anecic, which means ‘out of the earth.’ These worms burrow vertically in the soil’s mineral layers, creating holes as deep as six feet below ground level. They can be as small as one inch or as large as sixty inches in length.

Species of Earthworm

  • The Oligochaeta subclass of terrestrial worms has over 1,800 species worldwide. Lumbricus terrestris is the most common earthworm species found in the environment.
  • According to the species name database, there are currently over 6,000 terrestrial earthworm species, with only about 150 of them being widely distributed worldwide. These are peregrine or cosmopolitan earthworms. The list below consists of a few common earthworm species around the world. 

Redhead Earthworm

  • This worm originated in Western Europe, but it has spread throughout North and South America. It has been discovered living in the top layers of soil or among piles of decaying leaves. The common name, ‘Redhead worm’ comes from the fact that this worm has red-purple pigmentation on one end. It grows to be about four to five inches long when fully grown. It can be distinguished by the way its tail flattens out to form a paddle shape.

Common Earthworm

  • This species, also known as the dew worm or lobworm, is native to Western Europe. It is an invasive species that feeds on leaf piles and the soil’s top layers. They have powerful muscles that allow them to flee from predators like foxes, shrews, and birds. They have a reddish-brown pigmentation on one end. They are most visible during wet weather and may dig holes in the top layers of soil during dry seasons to avoid both heat and predators.

Green Worm

  • The green worm gets its name because some of these worms have bilin pigment, which gives them their green color. However, because most of these worms are pink morphs, you are more likely to come across a green worm that is pink. The genuinely green variations are more common in grasslands, though scientists aren’t sure why. The pink morphs have a slightly yellow-colored ring near their top end, and three sucker-like discs can be seen on the underside of the saddle, if you look closely. These worms grow to be about two inches long when adults.

European Nightcrawler

  • This worm is also known as the Greenhouse worm or the Compost worm due to its growing popularity in compost production. They have tails that are paler than the rest of them and are heavily banded with stripes. They prefer moist or damp environments, such as compost heaps, piles of decaying leaves, or organic garden waste.

Brandling Worm

  • The brandling worm, also known as the Tiger worm or Trout worm is a European native introduced to every continent except Antarctica. It has bristly hair-like structures on each segment that can cling to surfaces and help the worm move forward or backward by pushing or pulling it.

Giant Gippsland Earthworm

  • This worm is native to Australia and is one of the world’s most enormous worms, measuring 30–40 inches in length. The head is dark purple, and the rest of the body is pink-gray. It thrives in moist, deep soils near rivers and streams. They dig complex burrows of two feet on average but can dig as deep as five feet. They eat roots and other organic matter in the soil, but they will occasionally poke their heads above ground in search of food. The population of this worm is known to be declining, and it is threatened by soil cultivation and modern farming practices. The worm’s slow growth and low reproduction rate make it difficult to increase its population.

Washington Giant Earthworm

  • This rare worm was discovered near Washington in 1897, but by the 1980s, it was thought to be extinct due to a lack of sightings. Despite environmental organizations petitioning for it to be recognized as an endangered species, the worm is now considered vulnerable to conservation. It has been known to burrow to depths of around 15 feet, with the deepest level occurring during the summer to avoid drought. This worm is thought to be able to grow more than three feet long, but recent discoveries reveal that it is only half that length. It is colorless and can appear white, pale pink, or translucent. 

Gray Worm

  • This worm lives in the top layers of soil in non-permanent burrows in the United Kingdom. It is usually two to three inches long and has a distinct color pattern. The front end is divided into three segments, pink, gray, and brown.

African Nightcrawler

  • This worm is native to West Africa, but it has spread throughout tropical and warm regions, with temperatures averaging 75 °F – 85 °F. It’s easy to spot this worm because it’s dark purple and shiny. It has a thin point at the back. This worm is well-known for speeding up the decomposition of composting materials.

Composting Worm

  • This is a tropical worm that originated in the Himalayan mountains. This worm is now mass-produced for composting. It’s known for producing worm castings quickly, which aid in the quick decomposition of compost, and it’s recently gained popularity in the North American market as the popularity of home composting has grown. It thrives in wet environments.

Earthworm Life Cycle

  • Like many other life cycles, the earthworm begins with an egg. A young earthworm develops inside the egg until it is ready to hatch. The egg is encased in a cocoon, which is an egg casing.
  • Cocoons are typically shaped like a lemon, but the exact shape varies by species. The time it takes for them to hatch is also highly variable, varying by species and by environmental conditions.
  • Hatchlings resemble mini-earthworms, only smaller and paler. As the hatchling grows and feeds, its color will resemble that of an adult earthworm.
  • Juvenile earthworms look like an adult earthworm, but the clitellum is absent.
  • Adult earthworms are hermaphrodites, meaning they have both male and female reproductive organs.
  • Sexual reproduction happens when two earthworms, known as simultaneous hermaphrodites, are involved in the reproductive process. Earthworms produce a slime tube and use the tubercula pubertatis to grip each other during sexual reproduction (located on the saddle). The slime tube creates the ideal environment for the worms to exchange sperm, with each earthworm storing its partner’s sperm for later use.
  • A mucus sheath forms around the clitellum and follows the earthworm until it reaches the head end. It collects the earthworm’s egg(s) and sperm along the way. The cocoon is formed by this mucus sheath, and the egg is fertilized within it.

The Benefits of Earthworms

  • Worms are not very attractive or well-liked by humans, yet they play an essential role in our environment from which we, as humans, benefit directly.
  • Earthworms enhance soil nourishment. Earthworms eat organic materials that have decomposed, such as leaves, dead plant roots, and manure. These nutrients are concentrated in the worm’s digestive system before being released into the soil via the expelled earthworm’s cast. These casts are high in nutrients, particularly nitrogen and phosphorus, and are frequently left in wormholes. This means that nutrients are readily available to plant roots in burrows beneath the soil’s surface.
  • Earthworms help to decompose organic matter. Worms are an important part of the soil, as they help break down organic matter and provide food for bacteria and fungi that aid the decomposition process. A worm-cast-rich soil is likely to have 1,000 times more beneficial bacteria than soil without worms. Bacteria and fungi thrive on the nutrients released by earthworms, and they are an essential food source for other soil-dwelling creatures. 
  • These microbes play an important role in compost decomposition and are an important part of our ecosystem.
  • Earthworms help in improving the soil structure. Earthworms have been shown to improve soil structure by digging holes and opening up spaces within the soil. Water and soluble nutrients can travel down to the plant roots more easily as a result of this physical change. As a result, worm-inhabited soil is less likely to experience flash flooding than non-worm-inhabited soil.
  • Earthworms as a source of food. While earthworms are beneficial to our soil and plants to keep their populations alive, we must remember that earthworms are an important food source for many predators, such as birds, frogs and moles. Some animals, such as endangered land snails, would become extinct if they didn’t have earthworm populations to feed on.

Earthworm Worksheets

This is a fantastic bundle that includes everything you need to know about Earthworms across 22 in-depth pages. These are ready-to-use worksheets that are perfect for teaching kids about Earthworms, which are small, soil-dwelling invertebrates and are good biological indicators of soil health.

Complete List of Included Worksheets

Below is a list of all the worksheets included in this document.

  • Earthworm Facts 
  • Unscramble Me!
  • Internal Worm
  • External Worm
  • Hole of Truth
  • Worm Benefits
  • Worm Link
  • Crossworm
  • Wormy Sketch!
  • Earthworm Life Cycle
  • Decoding Worms

Frequently Asked Questions

Are earthworms harmful or useful?

Earthworms are extremely useful and beneficial to the environment. They are important indicators of the health of the soil. Earthworms are important for aerating the soil and converting dead plant material into minerals and nutrients for living plants to use.

How long do earthworms live?

Different species of earthworms live for different lengths of time. It’s typical for an earthworm to live between one and two years – if it doesn’t get eaten by a bird! But some can live for as long as eight years!

What do earthworms eat?

Earthworms are detritivores, which means they are decomposers that eat dead, organic material. Earthworms will munch through the soil and digest any dead plant material in it.

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Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

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