the secret lives of ice worms

Berg Lake Twilight. Photo credit: Jeff P. (2010). NB: ice worms can't live here.

Twilight in the alpine. The glacier quivers with the last remains of the day’s heat, its wide flat tongue spread languidly across broad gravel flats, like the pseudopodium of some gargantuan amoeba; gray heaps of stone and glacial slag dot the lonely moraine in conical piles. Higher up, the last light of the sun paints the peaks pink and gold; the landscape silent but for the rare croak from a raven hunched atop a wind-blasted pine. A cold blue shadow creeps up the ice, crawling toward the snow line like a shadowy army or a shroud pulled over the day’s light and life and warmth. In its wake follows a tide of squirming black worms, naked and blind, drawn upward by their hunger from secret lairs deep in the blue-veined ice. Soon thousands, millions of them writhe and wriggle on its surface—voracious, omnivorious, insatiable creatures of the night.

The scene reads like science fiction but it could just as easily be a (rather dramatic) rendering of a summer evening in the Cascades. Starting in spring, usually June, on certain glaciers on the Pacific coast of North America, droves of tiny worms emerge on the ice surface at dawn and dusk to bask in the cool night air. The ice worm, Mesenchytraeus solifugus ("solifugus" means sun averse) has long been a friend of fiction. A favorite character in Canadian ballads and tall tales of the Pacific Northwest, the ice worm first makes it into press in 1898 as a fictional monster invented by Yukon journalist, E. J. "Stroller" White, who was hard up for some real news. According to White, ice worms crawl out of the glaciers during particularly cold spells to keep the residents of Dawson City awake with their incessant chirping.

Around the same time as White's hoax, a song popular with early Klondikers, When the Ice Worms Nest Again, told a tale of high latitude romance, in which a man pins his hopes for marital happiness on the seasonal return of the worms to their nests. Its refrain:

In the land of the pale blue snow,

Where it's ninety-nine below,

And the polar bears are roaming o'er the plain,

In the shadow of the Pole

I will clasp her to my soul,

We'll be happy when the ice worms nest again

The song was recorded by cowboy crooner Wilf Carter —aka "Montana Slim"— and by Canadian folksinger Alan Mills. The latter recording was part of a collection titled “Canada’s History in Song,” made by the Smithsonian Center for Folklore and Cultural Heritage in 1960; it sat alongside songs about animals and nature, cowboy tunes, maritime ditties, heroic tales, sea chanties, mining dirges, and songs of "wit and humor." Pretty Canuck, eh?

But Canadians were not the only ones hot for ice worms. During the 1930s, a five-step partner dance called “The ice worm wiggle” was popular in bars of Juneau, Alaska. The slow fox-trot tempo was accompanied by lyrics written by Carol Beery Davis, state poet laureate from 1967-69. In her chorus, Davis sought to incorporate the local Tlingit language:

Ahk-tu-weh-yu-keh, O Cheechako! ——Yippee!

Ahk-tu-weh-yu-keh, O Cheechako!

("Cheechako" refers to untested newcomers to the northern mining districts.)

Perhaps the most famous homage to the lowly worm is Robert Service's “The Ballad of the Ice Worm Cocktail.” In this poem, the "Bard of the Yukon" recounts the hijinks of Dawson City locals when a cocky Cheechako strolls into town as if he owned the north. First frightening him with tales of six-inch-long, blue-faced, hairy, cannibalistic worms, they then cajole him into drinking an ice worm cocktail to prove he has the grit of a genuine sourdough (a name given to locals in those parts). Dawson bars still celebrate the tradition of the ice worm cocktail, though most imbibers today know the "worm" to be a strand of bloated spaghetti.

More recently, ice worms have been the inspiration for much science fiction graphic art. And perhaps also for the ice-dwelling insectoid alien that pursues the young James T. Kirk straight into care of an aged Spock, who, wielding a fiery brand, beats back the many-mouthed beast. Apparently alien ice worms don’t like heat either.

Microphotographic close ups of M. solifugus suggest a likeness between it and the alien that hunted Kirk in Star Trek: Enterprise. Image source: Alaska Public Lands Information Source.

As bizarre as science fiction can be, reality often trumps it in this respect. During the Cold War, "ice worm" was eponymous with the code name for an American military undertaking. Project Iceworm burrowed deep below the Greenland icecap, using reinforced ice to build a nuclear-powered city made of snow tunnels: Camp Century. The ultimate aim was to thus build hidden missile launch sites, but the results of Project Iceworm were less than promising. The movement of the mighty Greenland icecap could not be stopped by military means.

Camp Century, 1958-66 Camp Century, 1969.

Photographs via Frank J. Leskovitz

Biologists know little about the real ice worm, M. solifugus. The first scientific reportage on them came from glacial geologist George Frederick Wright in 1887 during his explorations of Muir Glacier. Since then, scientists have mapped their distribution along the Pacific coast from Oregon to British Columbia, where they disappear for about 400 km, only to pick up again in the Saint Elias Range of southern Alaska before continuing northwest to the Kenai Peninsula. The populations north and south of the 400-km gap are genetically distinct “clades” and so it is surmised that they split off sometime around 0.5 million years after the start of the Pleistocene ice age (about 2.5 million years ago).

Ice worms are very particular about their temperatures. Their dark pigmentation helps protect them from the sun's radiation, but they can only survive within a narrow range +/- 7 degrees Celsius. Below -10C, they dehydrate and freeze, which is why they are not found in the harsher climes of the interior mountains or elevations higher than 1200 meters. They cannot stand the terrible cold. Yet the more striking transformation occurs on the other side of the spectrum; above 10C, ice worms die and their proteins denature causing them to lose their structure. In warm weather, ice worms, like their glacial habitat, melt.

Ice worm against fingernail. Photo credit: Southwick3 (2004).

The physiology and behavior of ice worms is largely uncharted territory. Structurally, they are segmented worms—annelids—and closely resemble the commonplace earthworm, but with several unique adaptations. Ice worms possess anti-freeze proteins that enable them to thrive in freezing temperatures, and, unlike every other organism, when the temperature drops, their metabolism spikes. Adenosine triphosphate (ATP) is the unit of currency in cell metabolism, and its levels indicate energy usage; in most organisms, ATP levels drop as temperatures lower, but in ice worms, they rise, suggesting that the worm's cells go into overdrive as its environment cools.

Biologists believe that ice worms subsist on algae—like that which causes the pink color of “watermelon snow”—and bacteria, but their diet is largely a matter for speculation. Observing the dining habits of tiny, cold-loving annelids that come out only after dark turns out to be a tricky business. Their predilection for glacial pools, where they have been found anchored to a side wall by their posterior end and dragging for microscopic goodies with their anterior end, suggests to some scientists that a distant evolutionary ancestor of the ice worm was aquatic. They have also been found clustered in glacial pools in large numbers, writhing and wriggling in what is assumed—because other segmented worms do it—to be a reproductive behavior.

Chlamydomonas nivalis, "Watermelon snow." Photo credit: Ökologix 2009.

In 2012, Canadian indie artist and omnichord enthusiast, Jenny Omnichord revived the tradition of ice worm in song. In her factually-informed version of When the Ice Worms Nest Again, the worm is not a natural rhythm serving to structure the passage of time in northern courtship rituals, but an indicator of global warming and melting glaciers. Ice worms do not migrate easily—the genetic isolation of individual populations suggest that they don’t get around much. As glacier ice melts at higher and higher elevations during the summer months, the worms are pushed upward; even if they manage to outrace the great melt, it is not certain that they will survive the colder winter temperatures up high.

Ms. Omnichord’s song, though following the line of a longer cultural lineage, tacks its own course. Her lyrics, informed by the best science of her day, are a melancholic mediation of how to relate to her northern heritage when “our cold isn’t so cold…” and “soon even night will be too warm…”

It might be cold, but one day I hope for them

To find a cold that’s cold enough

For the ice worms to nest again.

To learn more about ice worms, please click on the following links:

North Cascades Glacier Climate Project

Dial et al, "The Role of Temperature in the Distribution of the Glacier Ice Worm" (preprint)