40 Fun Facts About Earthworms

Charles Darwin's earthworms ignored a bassoon but fled when their pots were set on which instrument?

A piano sent its vibrations up through the pots, and the worms shot into their burrows the moment a note was struck. Darwin concluded they are deaf to airborne sound but feel tremors in solid objects.

What wiped out the native earthworms of most northern North American forests thousands of years ago?

Glaciers scraped much of the continent down to bedrock during the last ice age, taking the worms with them. The earthworms in those forests today mostly descend from European and Asian arrivals.

Which mammal stocks underground larders with earthworms it has left alive but unable to crawl away?

Mole larders keep earthworms alive but immobilised, so the catch stays fresh. Researchers have found stores holding hundreds of worms.

When an earthworm is cut in two, which lost part is it most likely to be able to regrow?

Its tail is the part an earthworm can most readily replace, while a lost head is hard or impossible to regrow. That is why a worm cut in half very rarely becomes two worms.

At which ancient English monument did Charles Darwin study how earthworms buried toppled megaliths?

Stonehenge was worth a special excursion to Darwin, who found some of its outer blocks partly sunk, with the turf sloping up to meet them as worms raised the soil around them.

Charles Darwin wrote that earthworms did which farm job long before humans invented a tool for it?

Plowing was the comparison: Darwin praised the plough as one of humanity's oldest inventions, then noted that worms had been turning the land over long before people existed.

In the Earthworm Jim video games, what falls from the sky and turns a worm into a superhero?

A robotic suit lands on Jim and gives him a humanlike body, though outside it he remains a vulnerable worm. He even uses his own body as a whip.

Which sound gives away Australia's giant Gippsland earthworm as it slides through its wet burrows?

Gurgling carries up through the soil when the metre-long worm moves quickly along its tunnels. The noise is how people detect a species that rarely comes to the surface.

Lacking lungs and gills, an earthworm takes in oxygen through which part of its body?

Its skin does the breathing, but only while it is moist enough for gases to dissolve and pass through. A worm whose body dries out will die.

Earthworms have no eyes, yet special cells near the front end still let them sense what?

Light registers through photoreceptor cells scattered over the body wall and packed most densely at the front end. A strong beam sends a worm straight back into its burrow.

Which blood-feeding animals are close relatives of earthworms within the phylum of segmented worms?

Leeches belong to the annelid group alongside earthworms, with soft segmented bodies that stretch and contract. Like earthworms, each one carries both male and female organs.

The old nickname angleworm records the earthworm's long service in which outdoor pastime?

Fishing with a hook and line is called angling, after an Old English word for a fish hook, and earthworms have long been threaded on as bait.

Which name do North Americans give Lumbricus terrestris, the big earthworm sold mostly from Ontario?

Nightcrawler fits a worm that comes up after sunset to feed and mate on the surface. It is the example earthworm for millions of biology students, even in places where the species does not occur.

Which children's author created Lowly Worm, the Busytown earthworm who is Huckle Cat's best friend?

Richard Scarry called Lowly his favourite character, and drew him driving a street sweeper and helping in the Busytown hospital. In his earliest cartoon appearances the worm did not speak at all.

Which oxygen-carrying pigment floats dissolved in an earthworm's blood plasma instead of inside blood cells?

Hemoglobin drifts free in an earthworm's plasma instead of being packed into cells as it is in people. It picks up the oxygen that seeps in through the worm's moist body wall.

Which word, better known from the insect world, names the capsule where earthworm eggs develop?

Cocoon is the term for the sealed, onion-shaped capsule that slips off the worm's body and is left in the soil. The young emerge as tiny worms, with no larval stage.

What are the small coiled heaps of digested soil that earthworms leave on a lawn called?

Casts hold more plant-ready nutrients than the soil around them. A lawn dotted with the heaps is a sign of healthy, biologically active soil.

Which small earthworm, also called the tiger worm or brandling, is the usual choice for worm bins?

Red wiggler worms thrive in rotting vegetation and manure, not ordinary soil, so a box of kitchen scraps is ideal for them. Handled roughly, they give off a pungent liquid, hence the species name fetida.

What name is given to the fertilizer made when earthworms break down food and garden waste?

Vermicompost holds its nutrients in a water-soluble form that plants take up easily. The worms most used to make it thrive in shallow bins, feeding on decomposing plant matter.

Which muscular organ grinds an earthworm's food, using swallowed grit in place of teeth?

Gizzard walls squeeze hard, crushing each mouthful against mineral grains the worm has swallowed. The resulting fine paste moves on to the intestine to be digested.

Annelida, the phylum of earthworms and ragworms, takes its name from a Latin word meaning what?

Little ring is the meaning of the Latin anellus, a nod to the bands that mark off each body segment. The phylum holds more than 22,000 species.

Which tiny bristles on almost every segment let an earthworm grip the soil as it crawls?

Setae anchor one part of the body while the rest stretches forward. Special ones on the belly even hold two worms together while they mate.

Which saddle-like band near an adult earthworm's front end shows that it is ready to breed?

Clitellum is the name of the swollen band, which appears only once a worm is sexually mature. It later secretes the sleeve that slides off the body to hold the eggs.

When two earthworms pair up on the surface to mate, what does each one pass to the other?

Sperm travels in both directions because every earthworm is a hermaphrodite, carrying male and female organs at once. Each partner stores what it receives and later uses it to fertilise its own eggs.

What fills the body cavity of a boneless earthworm, acting as the skeleton its muscles push against?

Fluid held under pressure in a chamber called the coelom gives the worm its firmness, an arrangement known as a hydrostatic skeleton. Squeezing it is how the animal alters its shape.

Which five paired structures near an earthworm's front end pump blood and are often called hearts?

Aortic arches loop around the gut in segments seven to eleven, squeezing blood down to the vessel that runs along the belly. Blood returns forward through a vessel along the back.

Unlike a human spinal cord, an earthworm's main nerve cord runs along which part of its body?

The underside carries the nerve cord, which swells into a small knot of nerve cells in almost every segment. A two-lobed brain sits above the gut near the front.

An earthworm stretches longer and thinner when which set of muscles in its body wall contracts?

Circular muscles squeeze a segment the way a hand squeezes a tube of toothpaste, forcing it to lengthen. The longitudinal set then shortens and fattens the segment, pulling the rest of the body along.

Which muscular part of an earthworm's gut works as a suction pump to draw food into the mouth?

Pharynx walls are thick with muscle that draws food in, while glands there coat each mouthful in mucus. The food then moves on down the gut to be crushed and digested.

Which fleshy lobe overhangs an earthworm's mouth and helps it feel and taste its surroundings?

Prostomium means before the mouth in Greek, and the lobe seals the opening when the worm rests. Some species use it like a finger to grab leaves and drag them into the burrow.

Which paired tubes, found in most earthworm segments, filter waste from the body like tiny kidneys?

Nephridia draw waste out of the liquid in the body cavity and expel it through pores on the worm's sides. Most segments carry a pair of them.

Which internal fold runs along an earthworm's intestine, adding surface area to absorb nutrients?

Typhlosole is the name of the fold, which hangs from the roof of the gut like a tube within a tube. A mammal gets the extra surface by coiling its intestine instead.

The yellow chloragogen cells around an earthworm's gut do a job like which organ in vertebrates?

Liver work is the closest match: the cells store glycogen and fat, break down proteins and neutralise toxins. They also collect nitrogen waste for the worm to get rid of.

Which term describes earthworms that dig permanent vertical burrows and come to the surface to feed?

Anecic worms are the deep burrowers, coming up to gather fallen leaves and pull them underground. The other two groups keep to the litter layer or tunnel sideways through the topsoil.

Which English county hosts the World Worm Charming Championships, held in the village of Willaston?

Cheshire has staged the contest since 1980, when a farmer's son reportedly charmed 511 worms in half an hour. Digging is banned, so competitors twang garden forks to bring earthworms up.

Which accidental import from New Zealand has left Europe's common earthworm locally endangered?

A flatworm from New Zealand hunts earthworms beneath the soil and can last long spells without food, so it outlasts its prey. Where it spreads, the soil loses the mixing and airing that worms provide.

Some earthworms, such as Asian jumping worms, produce young without a mate through which process?

Parthenogenesis means each worm can produce young alone, with embryos developing unfertilised. That lets jumping worm populations expand quickly.

The rare giant Palouse earthworm of the US Northwest was long said to smell like which flower?

Lily scent is built into the worm's scientific name, Driloleirus, which means lily-like worm. Thought extinct in the 1980s, it has since turned up alive, though specimens caught in 2010 had no such smell.

Invasive Asian jumping worms leave droppings in the topsoil that look like which kitchen waste?

Coffee grounds are the telltale look of soil that jumping worms have worked over. The worms keep near the surface and strip the leaf litter, leaving plants shallow-rooted and easily washed away.

Which bird, nicknamed the timberdoodle, probes soft soil with its long bill mainly for earthworms?

Woodcock bills have a tip the bird can open and close while it is sunk in the soil, so a worm can be gripped out of sight. Its slow rocking walk may also coax earthworms closer to the surface.