They’ll boil up from the soil as you dig in the garden; they’ll appear in country stores in little tubs in the refrigerator case—sometimes upsettingly near the cream cheese. Even if you don’t fish or dig in the dirt, you’re sure to see them on sidewalks and streets after a hard rain.
Earthworms are as sure a sign of spring as the robins who eat them. Yet the birds always get top billing. And that really isn’t fair. True, earthworms may not be the world’s handsomest animals. (Aristotle referred to them inelegantly as “earth’s guts”—but he also thought earthworms formed by parthenogenesis and eventually became eels.) But no less an expert than Darwin championed earthworms: “It may be doubted whether there are many other animals which have played so important a part in the history of the world,” he wrote in his book on the creatures in 1892.
Without earthworms’ tunnels to oxygenate the soil and their feces, or castings, to enrich it, much of the Earth would be hard, cold, and sterile. And earthworms have many other amiable qualities as well. I like them,” says Samuel James, “because they’re toothless, nonviolent, and easygoing.” In fact, the Iowa professor likes them so much that he’s made a career of studying these companionable, though slimy, invertebrates.
Earthworms make fine gardening partners, good pets for young children (they can live up to six years), and entertaining guests in the home or school terrarium (where they will also eat your garbage and turn it into top-grade compost). Earthworms are far more interesting, important, complex, and mysterious than their pink, squashed forms on rainy sidewalks might suggest.
Few creatures are at their best after they’ve been stepped on (and alas, earthworms “have been getting stepped on ever since there were vertebrates to step on them,” James says). But even dead, they’re underestimated. “People think they’re just mush inside, but they’re not,“ says Ardis Johnston, an invertebrate zoologist at Harvard’s Museum of Comparative Zoology. It’s not as if earthworms have nothing between their ears. Actually they don’t have ears, but they do have brains—and hearts with valves, and blood, and many of the organs that we do.
To really appreciate earthworms, you need to encounter them alive and well in their natural element—like in your garden. Earthworms spend the day literally eating their way through the organic matter of the soil. Their meals aren’t random. They avoid eating their own castings, the world’s best plant food. Sometimes they drag choice morsels, such as fallen leaves, into their burrows for later snacking. (Occasionally you’ll even find a bird feather in there.)
Earthworms often construct their burrows under small rocks. (This is why flagstone footpaths tend to sink: worms are working beneath, moving the earth from below and piling it on the surface.) They line their tunnels with slime, which is one reason they can slip down them like greased lightning—so fast sometimes it’s hard to keep up with them with a shovel. Once James hacked away at the earth for half an hour during a titanic struggle with a previously undescribed Puerto Rican species. (He estimates that, amazingly, perhaps more than a hundred species of American earthworms are still undescribed! About seventy are known so far.) The scientist eventually won, and got out the thirty-nine-inch-long animal, albeit in three pieces.
Contrary to popular belief, cutting up a worm into pieces doesn’t create extra worms. Many earthworms—especially darker species who live near the surface—can regenerate their tail ends, but their tails can’t grow new heads. The Austrian ethologist Konrad Lorenz observed that most worm-eating creatures seem to select the worm’s tail end, but this may in fact reflect the worm’s preference instead.
If you have hold of one end of a fleeing earthworm, you’ll marvel at its strength as it pulls down into its burrow. Earthworms use tiny hairs called setae and two kinds of muscles to move. “Like the claws of a cat,” as Mary Appelhof puts it in her book Worms Eat My Garbage, these hairs can extend or retract and act as brakes. The stiff setae push against a surface to keep that portion of the worm from moving while the muscles contract. Short muscles circling the worm’s body tighten to make the worm long and thin. Lengthwise muscles pull the segments of the worm closer together, causing the worm to shorten and swell. It’s in this position that worms are most easily picked up—but you need to be quick at it, because they’re soon off and tunneling again.
Earthworms know that strong light and being touched are bad signs, usually indicating something is coming to eat them. Even though they don’t have eyes, they can detect light with special cells located all over their bodies. Though they don’t have noses or tongues, they have thousands of chemical receptors—as many as seven hundred per square millimeter of worm.
Oddly, if a worm is near the surface, its response to danger is to come up to escape. In Florida, bait collectors—“worm grunters” as they are sometimes referred to—“call up” worms by pounding a wooden stake into the ground and then rubbing a coarse piece of wood across it; in Missouri, professional grunters use gas-powered soil tampers.
You may not need to dig or grunt to find worms in the spring. If you walk softly, you’ll see some species of worms—nightcrawlers—out of their burrows on your lawn in the early morning or evening. This time of year, they emerge from the earth at night and make love in the wet, green grass.
Earthworms copulate as we do—sort of. They mate belly to belly, but (literally) with a twist: head to tail. (How can you tell? The band of swollen tissue on a mature worm, the clitellum, is located more toward the front half.) Because earthworms are hermaphrodites, what both partners are doing is swapping sperm. They’ll be at it for up to three hours, joined by two bands of slime emitted by each partner’s clitellum. A few days later, each worm will lay its eggs in a cocoon constructed of hardening slime. You’ll encounter these lemon-shaped, yellowish cocoons as you garden.
Unfortunately, most folks’ longest looks at earthworms happen on sidewalks and streets when spring rains flood the worms’ burrows. Most of these poor creatures are about to be drowned, fried, or smooshed. (The ultraviolet rays of the sun are worms’ worst enemies, according to James: “They need SPF thirty or forty just to stay alive,” he says.)
“These exposed, pink, hustling worms are truly needy,” writes Doris Gove in an essay titled “Something You Can Do if You Don’t Have Time to Patch the Ozone Hole.” So what can one person do? “Help them,” exhorts the essayist. If this is a mass evacuation, suggests James, you might want to lift them (not stab them) with a plastic fork. Place each worm three to four feet back from the pavement, so they won’t wander out again. And if people stare, Gove has two suggestions: a) invite them to help, or b) talk to the worm as you pick it up.