Have you ever been on a glacier in western North America and noticed worms coming out from the top of the glacial ice? Have you ever wondered how worms are able to survive in such an extreme environment? Have you ever considered what worms might eat on such seemingly barren terrain? Have you ever imagined why such worms might require a cold icy home rather than a warm environment? If you answered “yes” to any of those questions, then this article might be suited for you.
Yes, as illogical and improbable as it might appear, there are species of segmented worms that live their entire lives on and in glacial ice. They are appropriately named ice worms, small organisms that are more abundant in western North America than most people probably realize. But despite their tiny sizes, ice worms are important to glacial ecology.
In many respects the life of an ice worm is similar to that of its more-common segmented relative, the earthworm. Similar to how an earthworm makes its home in dirt (earth), an ice worm makes its home in ice. Similar to how an earthworm consumes organic material, so does an ice worm. Similar to how an earthworm provides a valuable food source for other animals, so does an ice worm. Similar to how an earthworm is sensitive to acidity levels within its environment, an ice worm is sensitive to changes in heat levels.
Ice worms were officially discovered during 1887 by geologist George Frederick Wright on the Muir Glacier in southeastern Alaska. Since then, similar ice worms have been discovered on many other glaciers in the states of Alaska, Washington, and Oregon, as well as the Canadian provinces of British Columbia and Yukon Territory. It is unknown how or why the worms evolved to thrive in such a seemingly harsh environment. However, it would not be outside of the realm of possibility if the original adaptation occurred during one of the last major Ice Ages while glacial ice sheets covered western North America from the North Pole to California.
All ice worms are species of the genus Mesenchytraeus. The most common species of ice worm is Mesenchytraeus solifugus, a scientific name first chosen by Italian entomologist Carlo Emery during 1898. The species name of solifugus means “sun-avoiding” in Latin. This name was given to the species because of its natural tendencies to retreat back under glacial ice surfaces before dawn. Other species of ice worm include M. harrimani, M. kuril, M. maculatus and M. obscurus. A sample micrograph of a glacier ice worm is shown at this link.
It was English poet Robert William Service who helped give widespread fame to ice worms. He only lived in Canada for seven years, at the turn of the 20th Century, but during that short time period he became aware of the existence of ice worms… or at least tales of them. One of the most famous examples of this occurred in a short poem written within his 1910 novel “The Trail of ‘98”:
Another example, and one which took Robert Service’s recognition of ice worms to a whole new (and quite jovial) level, is his bar-room poem titled “The Ballad of the Ice-Worm Cocktail”:
The poem seems to imply that Robert Service knew of the existence of ice worms, despite their official discovery no more than 15-20 years earlier. The poem definitely gave rise to the awareness of ice worms to a wider audience, worldwide. Unfortunately, the poem was also occasionally taken too literally by some readers and ice worms were misunderstood as a result.
Robert Service’s poetry certainly spread awareness of ice worms worldwide. However, ice worms were also misrepresented in his literary works. In example, in “The Ballad of the Ice-Worm Cocktail” he wrote “Since ice-worms are peculiar to the Mountain of Blue Snow.” Unfortunately, some readers interpreted that as ice worms being responsible for giving glacial ice a blueish coloration, for which they have no influence. In another example of misrepresentation in the same poem, he wrote “Yet on this stern and Spartan fare so-rapidly they grow, That some attain six inches by the melting of the snow.” Unfortunately, some readers interpreted that as ice worms growing to massive sizes (at least in comparison to most common worms), which was also false.
Outside of Robert Service’s works, other myths have been present in regards to ice worms. As one example, contrary to popular belief true ice worms only exist naturally on glaciers in North America. Other types of worms commonly resemble ice worms in appearance and/or behavior, both in North America and on other continents, which can cause confusion for identification purposes. As an example, young earthworms will occasionally roam atop snowfields and snowbanks during periods of pre-dawn darkness, similar to how ice worms do on glacial ice.
Such misrepresentations and presumptions should not be too surprising. Throughout years of human history, many creatures have been misrepresented which were not yet fully understood. Whether it is the lack of intelligence of the now-extinct dodo, or the presumed extinction of the ancient Coelacanth fish, or the ability of using tools being a human-only trait in the Animal Kingdom, or the enormous size of the ice worm, misrepresentations have existed in many circumstances for which humans have not yet discovered or understood to the contrary.
In reality, ice worms have some interesting qualities. Depending on species, ice worms can be different colors. Most ice worms encountered are colored black or dark brown, but some have been known to appear to be colored red, blue, or white.
Unlike the false presumptions implied by Robert Service’s writings, ice worms do not grow to massive sizes or “attain six inches by the melting of the snow.” In fact, ice worms never come close to growing six inches in length. In contrast, ice worms are tiny organisms, only reaching a maximum of 1/2”-1” (approximately 1-3 cm) in length and 1/32” (nearly 1 mm) in width during their lifetimes.
Despite their small stature and harsh environment, ice worm populations actually tend to thrive on North American glaciers. During evenings and pre-dawn mornings, ice worms can commonly be seen atop glaciers in western North America, usually having the appearance of small strands of thread. Some glaciers have larger ice worm population densities than other glaciers.
To give one example, during year 2002, the North Cascades Glacier Climate Project (NCGCP) was doing research on the Suiattle Glacier of Glacier Peak, in the north-central Cascade Mountains of Washington. They estimated a mean density of ice worms on the glacier at 2600 ice worms per square meter. With an overall glacial area of 2.7 square kilometers, that meant the Suiattle Glacier had an estimated population of over seven billion ice worms. As concluded on the NCGCP website: “This is more than the earth's entire human population on just one glacier.”
External temperature is a very important aspect for an ice worm population. Ice worms have evolved and adapted to a very specific type of environment: glacial ice. Although glacier surfaces can commonly have sub-freezing temperatures, especially during Winter seasons, insulating properties of glacial ice allow temperatures below the ice surface to remain at or near freezing. As such, ice worms prefer living at near-freezing temperatures (32 Degrees Fahrenheit / 0 Degree Celsius). Each ice worm has anti-freeze proteins which prevent the body from freezing despite an external temperature at or near freezing levels. However, those anti-freeze proteins only help to protect ice worms at near-freezing temperatures. Ice worms will freeze if exposed to temperatures below 20 Degrees Fahrenheit (-6.8 Degrees Celsius).
Furthermore, perhaps the strangest aspect of ice worms occurs when temperatures rise above freezing. Once temperatures approach 40 Degrees Fahrenheit (nearly 5 Degrees Celsius), ice worms exposed to those temperatures have been known to gradually start to liquify. Yes, you read that correctly. If the external temperature is further increased towards 50 Degrees Fahrenheit (10 Degrees Celsius) or higher, then the virtual “melting” of the ice worms accelerates. At such temperatures above freezing, especially if sustained, ice worm death is imminent. This phenomenon occurs because heat causes enzymes within an ice worm to begin breaking down, a process known as autolysis.
Despite living on a seemingly barren type of environment, ice worms are able to find ample consumption on glaciers to thrive. Ice worms are believed to eat snow algae (also known as “watermelon snow”) and wind-deposited pollen grains. It is also possible that ice worms consume varying amounts of snow, ice, fungi, and bacteria. During cold Winter seasons, scientists have speculated that ice worms consume nutrient deposits trapped within glacial ice rather than spend much time (if any) on the surface of a glacier.
Similar to organic material providing consumption for ice worms on glaciers, ice worms provide consumption for other organisms on glaciers. Small birds and invertebrates are the major predators of ice worms. Some small birds commonly pull out and digest partially exposed ice worms during pre-dawn light, very similarly to how a robin might pull out and digest a partially exposed earthworm from dirt.
By both consuming organic material and acting as a food source for other organisms, ice worms are integral components for many glacial ecological cycles in western North America. Without glaciers, there would not be any food sources for ice worms. Without ice worms, there would not be valuable food sources for some types of larger organisms. Without larger organisms, there would not be ample supplies of fresh nutrients created to provide food sources for future ice worm consumption. Glacial ecology is an ongoing cycle.
Ice worms follow general daily routines. During Winter seasons, when surface temperatures are commonly below freezing, ice worms typically remain below the surface of glacial ice each day. However, during Spring, Summer, and Autumn seasons, when surface temperatures are more commonly at or above freezing, ice worms tend to follow a diurnal pattern. Ice worms retreat beneath glacial surfaces as daylight begins to hit the glaciers in the morning, and then ice worms return to glacial surfaces within several hours of sunset. Even if surrounding temperatures off a glacier are similar to those on a glacier, ice worms will continue to only live on and in glacial ice.
Despite a mostly diurnal routine, it is possible to occasionally witness ice worms on glaciers in broad daylight. During many such occurrences, ice worms can be found gathering in small glacial-melt streams and glacial ponds. Some scientists speculate that the near-freezing water provides a suitable survival temperature for ice worms, and the water itself prevents some potentially harmful sun wavelengths from passing through. It is possible that some ice worms use this type of situation as an optimum breeding opportunity, as the normally solitary worms are commonly found grouped in much closer proximity of each other when within glacial water.
Ice worms appear to have fairly smooth bodies, but they actually have tiny external bristles called setae. The setae allow ice worms to move through and along ice without slippage or difficulty. The setae are very effective for ice worm mobilization; some ice worms have been measured moving at a rate of 10’ (3 meters) per hour atop glacial ice.
Nobody knows with certainty how long ice worms live in their natural habitats. Some scientists speculate that the lifespan of an individual might last as much as 5-10 years. But one thing is certain: ice worms have developed an ability to withstand somewhat extreme conditions and circumstances. In example, ice worms kept in laboratory freezers have been known to survive more than one year without eating.
In addition to the poetry of Robert Service mentioned earlier, ice worms have been mentioned or represented in other areas, too. Another literary example is the song “When The Ice Worms Nest Again,” an old Canadian song which even Robert Service later used as inspiration for a poem (of the same name) written for his “Twenty Bath-Tub Ballads” which was published during 1938. Although the exact origins and author of the song are not known, “When The Ice Worms Nest Again” may have been present as far back as the Klondike gold rush of 1898, and during the early-to-mid 1900s became a popular song amongst prospectors and fur-trappers throughout Canada.
Different variants of the song have existed, with perhaps the most famous version being Wilf Carter’s rendition (with lyrics listed below):
Fascination with ice worms has not stopped with poems and ballads. The city of Cordova, Alaska, has an annual celebration dedicated to ice worms. Each year, Cordova hosts the appropriately named “Ice Worm Festival” during the first full weekend of February. The festival started in 1961 as a fun way to spend time during the otherwise uneventful Winter season. The city created a legend that ice worms hibernating in the nearby Cordova Glacier started to emerge from the glacial ice in early February. The highlight of the festival is a 50'-150' long (15-45 meters long) ice worm leading a parade, similar to a Chinese New Year dragon dance.
Science-fiction has also taken notice of ice worms. At least partially (if not mostly), ice worms appear to have helped inspire creatures in the novel “Fallen Dragon” by Peter F. Hamilton as well as the short story “Glacial” by Alastair Reynolds. Another example of ice worm influence within the science-fiction genre occurred during 1993, when the science-fiction television series "The X-Files" aired an episode titled "Ice" about parasitic (and possibly extraterrestrial) ice worms infecting people in Alaska.
With these examples in mind, and considering the imagination and creativity that people can achieve, it would not be surprising if other people use ice worms as inspiration for future literary works and other projects.
Some people reading this article might find the topic interesting, and some might not. But if nothing else, the author of this article hopes its readers understand the following:
-> Ice worms require glaciers to survive.
-> As glaciers continually disappear, so do ice worms.
-> Take any opportunity to see both while you still can.
To help with the creation of this article, some information was compiled from the following website resources. Anyone interested in finding out more about the subject material covered in this article is definitely encouraged to visit these websites.
North Cascades Glacier Ice Worm Research
This website was created by the NCGCP, and contains research compiled by some of the foremost observers of glacier ice worms.
Alaska Public Lands Information Centers
This website is linked directly to a section regarding ice worms.
World Glacier Biology Program
This website contains an assortment of ice worm facts and history.
Website Dedicated To The Life And Works Of Robert William Service
This website provided text of several poems used in this article.
When The Ice Worms Nest Again
This website provided text and history for the song in this article.
Ice Worm Festival
This website provided basic information regarding the Cordova Ice Worm Festival. For further information, contact the Cordova Chamber of Commerce.
Any photo used in this article that did not originate from the author has been allowed with permission by the original photographer.
TO THE READERS: If any person has a photo of ice worms that he/she would like to have included as part of this article, please feel free to contact me with the request.
If you enjoyed reading this article, and/or found it interesting, perhaps you might also like to read the other articles in my "Exploring The Mystery Of" series:
Exploring The Mystery Of Watermelon Snow
Exploring The Mystery Of Summit Ladybugs