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Meet the giant Palouse earthworm, a rare American original

The giant Palouse is considered by experts to be the “Holy Grail” of North American earthworms.University of Idaho

Found only in a critically endangered ecosystem known as the Palouse prairie, a storied giant was long thought to be extinct. Only a handful of sightings have been reported since the 1970s. Today, there are only 10 of these animals in captivity in the world. Seeing a rare species is one of the highlights of a naturalist’s life — and earlier this month, in Moscow, Idaho, I was thrilled to have the opportunity to see one.

In the second-floor laboratory at the University of Idaho’s College of Agricultural and Life Sciences, PhD candidate Chris Baugher did the honors. From a plastic Tupperware container the size of a shoebox, and onto some moistened white filter paper, he dumped out several cups of black dirt. And there it was: a worm.


Not just any worm, mind you. This was a giant Palouse earthworm — portrayed in the media as a “spineless, subterranean Bigfoot,” described as “Moby Worm,” and considered by worm experts to be the “Holy Grail” of North American earthworms. I had read it was white, grew to more than a yard long, and spat saliva that smells like lilies.

The worm before us was none of the above. It wasn’t white at all — mostly reddish-purple with a handsome, peach-colored forward section. It was only about 8 inches long. And Baugher and soil scientist Dr. Jodi Johnson-Maynard, considered the world’s top experts on the animal, admit they’ve never been able to detect its scent.

To my untrained eye, it looked a lot like the common nightcrawlers they sell at the Hancock Market here in New Hampshire, to bait angler’s hooks.

But nightcrawlers — the reddish-gray species you find on sidewalks after a rain — are, like most earthworms now found in the US, an invasive species. They came to the United States in ballast to steady early ships from Europe. “Of the 6,000 species of earthworms,” explained Baugher, “very few are native. It may be that the giant Palouse earthworm has been here for a very long time.”


Shockingly little is known about any of our native earthworms. There is only one working earthworm taxonomist in America. International earthworm experts gather at a symposium only once every four years. The giant Palouse earthworm illustrates just how mysterious are the lives of the little creatures who live under our feet — animals to whom we give little thought.

But Johnson-Maynard reminds us that earthworms have profound effects on our lives. “To many people the soil is just a black box we walk on,” she says. But it’s the foundation of our food chain, and, she points out, importantly regulates gas exchange with the atmosphere. Soil sequesters three times as much carbon as the atmosphere, adds Baugher. And earthworms are soil’s stewards.

It’s difficult to learn about animals who live underground. Baugher and Johnson-Maynard have made plaster casts of their burrows. They have tried digging up the worms, but that’s a good way to accidentally cut them in half — not a good thing to do to a rare species. Genetic expert Dr. Lisette Waits is working on ways to identify their worms’ burrows by DNA gathered from swabbing mucus (which they secrete to speed their passage) from burrow walls.

“To cultivate the giant Palouse earthworm is a real chore,” said Johnson-Maynard. Nobody is sure what type of soil it prefers, how wet to keep it, or even what it eats. Nightcrawlers come to the surface at night and carry leaf litter down to their burrows to feed. Maybe the giant Palouse does the same; maybe not. “We’re just trying to keep them alive.” (That’s why the worm I saw was dumped out of its container; the researchers need to make sure their animals are still alive.)


Most of the specimens in captivity were brought in by one man, Cass Davis. He’s a self-described “liberal redneck,” an Earth First! environmentalist who feeds himself by hunting and fishing. “I’m quite familiar with worms,” he told me. “I’ve put a lot of worms on hooks.” He used to swallow nightcrawlers on a dare, to earn chewing tobacco as a teen.

Now 52, he found his first GPE in 2012 on a rut in a road. It had been run over, but even in this condition, it didn’t look like a nightcrawler. He brought it in to the university lab — and sure enough, it was the storied worm. He has a photo of it — and all the others he’s found — on his cellphone. “They have beautiful lips!” he told me as he displayed the picture.

Davis is one of many citizens of this corner of Idaho, including a number of farmers who have collaborated with the university scientists, who are proud to share the home of the giant Palouse earthworm. (Though some farmers — ironically, the very recipients of the worms’ hard work aerating the soil! — fear that if conservationists get the worm endangered status, it could restrict use of their land.) “Citizen scientists have been very important to the project,” says Johnson-
Maynard. Folks bring animals in to the lab all the time, hoping they’ve found the elusive worm. One person brought them a very small snake; another brought in a leech; another sent a photo of a long white thing that turned
out to be the intestine of a large mammal.


Still, Baugher and Johnson-Maynard are grateful to them all. They love it that the giant Palouse gets people excited about earthworms. “It’s unique to this region. It draws them in,” says Johnson-Maynard. “And it really is a beautiful animal.”

Sy Montgomery is the author of many books on animals, including “The Soul of an Octopus.” Send questions to syandlizletters@gmail.com.