On January 24, 2017 earthworms were still migrating across the road here in southern Maryland. To get to the other side? Has the warm weather confused them? Should I pick them up and tuck them into my houseplants before the ground freezes? Here’s what they’re supposed to do:
Earthworms in winter, like earthworms during drought (dry soil conditions), burrow deeply. Night crawlers, the biggest of the garden worms (at least in my neck of the woods) will tunnel as much as six feet down, taking organic matter with them. There they build permanent burrows and wait for moisture.
All earthworms do more than just burrow to escape frozen ground. Once down as deep as they will go, they curl up tightly, surrounding themselves in insulating slime. In summer, during hot and dry spells, they enter a hibernation-like state known as estivation. In winter, the worms hibernate, waiting for soil to thaw before moving upward.
“…It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.” — Charles Darwin (1881)
The lowly earthworm, they’re given such short shrift. With nary a thought from us, they quietly work magic day and night, right under our very feet. We should be celebrating earthworms, as the ancient Egyptians did, because they’re the unheralded champs of soil restoration. Aristotle called them “the intestines of the earth.”
Earthworms clean up debris and recycle it as fertilizer. Their tunnels aerate the soil and erosion is almost eliminated. Their labors benefit the food we eat, the flowers we love, the trees that shade us and the wildlife who live in our yards. And, the worms themselves are food for many animals. Around the world, agricultural areas are going “no-till.” In these instances, earthworms are valued as the main force for churning crop residue into the soil and keeping it fertile.
They’re strange-looking critters, aren’t they? But they’re perfectly built for the work they do, and they’ve been doing it successfully for a long time — maybe 1.2 billion years. In 2002, Australian researchers found a fossilized trail in sandstone they believe was made by a worm-like animal that long ago. This would not only be the oldest worm evidence, but the oldest multi-celled animal.