The Oregon Giant Earthworm | The Source Weekly - Bend, Oregon

The Oregon Giant Earthworm

A rare earthworm slithers beneath the Willamette Valley

This winter, a Bureau of Land Management timber project in Oregon's Coast Range became newsworthy because of the possible presence of an extremely rare and unusual creature: the Oregon giant earthworm (Drilolerius macelfreshi). Really, such a creature exists. Two independent sightings occurred in and around the project area, but remain "unconfirmed" because as Doug Heiken, Oregon Wild's conservation and restoration coordinator, explained it, "You pretty much have to dissect the worm to figure out its identity." For an incredibly rare species that hasn't been observed in Oregon since 2008, that's a tough hill to sled.

The Oregon Giant Earthworm
Mark Wigg
A possible Oregon giant earthworm from the Coast Range foothills.

If you're like me, the mention of giant earthworms brings to mind the massive sandworms of Frank Herbert's "Dune." Over 1,000 feet long, those sandworms inhabited the planet Arrakis where their existence was closely tied to the development of mélange, an incredibly precious cinnamon-like smelling spice that was used for making clothes, food and even interstellar space travel. Perhaps the Oregon giant earthworm holds a similar mystique on our planet, minus the space travel?

The earthworm's scientific name Drilolerius refers to a lily-like scent that the worm produces, possibly as a defensive mechanism, and macelfreshi honors the person who first collected the worm near Salem in 1903: F.M. MacElfresh. It would take another 35 years or so for an invertebrate biologist to describe the earthworm and name the species for science.

Like the sandworms of Arrakis, the Oregon giant earthworm also bears a mysterious aura in the Willamette Valley and parts of the Coast Range. When asked about the connection between the earthworm and soil types found in these areas, Candace Fallon, senior endangered species conservation biologist with the Xerces Society, said, "They are such an interesting part of our biodiversity and yet we know so little about them." Once abundant in the Willamette Valley, these earthworms are now considered critically imperiled on a global scale. "I like to think of giant earthworms as the terrestrial, subterranean cousins of the giant squid—poorly understood, rarely observed and cloaked in mystery," added Fallon.

Though it would seem that an earthworm that grows up to 4 feet long and produces saliva with a lily-like scent would be easy to study, they are elusive as Bigfoot. The worms create burrows 15 feet or longer deep underground in undisturbed fine-textured soils, which makes surface sightings rare. To compound matters, other large, native earthworms in Northwest woods may be confused with this species. Who knew!?

Over 100 native worm species occur in the Pacific Northwest, but most people only know the non-native European earthworm or the Asian jumping earthworm which compete with native worms for habitat. Interestingly, worm researchers believe the last glaciation period that scraped away the topsoil is why regions in the U.S. are devoid of native earthworms.

Mark Wigg, a retired timber cruiser, recently photographed a possible Oregon giant earthworm while out mushrooming with his daughter in a timber stand close to the Gone Fishin timber project. "I was a forester for decades and cruised timber in the foothills of the valley. Occasionally, after a heavy rain, I would smell lilies in January and February. I searched for the source of that powerful fragrance, but what was blooming at that time of year?" Wigg suspected giant earthworms but never found any. His recent sighting occurred in an area abundant with chanterelles, leaving Wigg to wonder if the worms help spread the mushroom's mycelium or spores as they burrow through the soil.

But back to the timber sale. To compound matters with the BLM's Gone Fishin' timber sale west of Eugene, the agency had removed the earthworm from its list of sensitive species some time ago, thus eliminating the need to consider impacts caused by this and any other activities of the worm. The reason: lack of information about the species.

“I like to think of giant earthworms as the terrestrial, subterranean cousins of the giant squid – poorly understood, rarely observed, and cloaked in mystery.”—Candace Fallon

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Though the Oregon giant earthworm might be the Rodney Dangerfield of the invertebrate world ("I don't get no respect"), these worms may play a major role in soil development through aeration and nutrients from their droppings. I can count the number of people I know who are into oligochaetology (the study of worms) on one finger and he's been dead a long time. Charles Darwin published, "The Formation of Vegetation Mould Through the Action of Worms with Observations on their Habits," in 1881. I'd like to meet William Fender, Oregon authority and author of a paper on Northwest earthworms, whose passion, not profession, is native worms.

In the 1970s the Oregon giant earthworm garnered attention by making the U.S. Fish and Wildlife Service's candidate list for Threatened and Endangered Species. Unfortunately, earthworms aren't charismatic megafauna and it was dropped from consideration. Heiken, with Oregon Wild, also likes to point out that even though the Pacific yew was once considered a "trash tree" in the forest, the eventual discovery of a cancer-curing compound in its bark has spawned a multi-billion-dollar industry. "It's just a reminder that there are magical things out in these forests and we shouldn't lose sight of these amazing creatures just because we don't know much about them," said Heiken.

Damian Fagan

Damian Fagan is a freelance writer, outdoor enthusiast and avid birder. He is the author of several wildflower field guides including "Wildflowers of Oregon" and "Wildflowers of North America." Fagan lives in Bend with his wife, Raven, and a pollinator-friendly garden.
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