Note: This Embedded video resides on the official Alaska National Park YouTube channel 

cartoon drawing of an iceworm
Cartoon depiction of an ice worm

Contrary to what many people say, iceworms do exist! However, they do not give the glacier ice its blue color, nor do they grow to lengths of 50 feet (both of these false statements were made popular by poet Robert Service and the annual Cordova Ice Worm Festival).

A member of the segmented worms, the annelids, iceworms are related to common earthworms and leeches. The iceworm (Mesenchytraeus solifugus) is a small, slim worm, one to three centimeters long, and dark brown or black in color. It resembles a miniature earthworm.

Surprising as it seems, iceworms live quite successfully in glaciers and adjacent perennial snowfields all year. Populations of iceworms can survive and thrive at temperatures around 32 degrees Fahrenheit, zero degrees Celsius. This might seem impossible, but actually the tissue in animal cells does not freeze at the same temperature as water. Most animals would die long before reaching this temperature. The iceworm has adapted to cold temperatures and functions best at zero degrees Celsius. The summer temperature of the glacier ice and slush usually stays at about zero Celsius. In winter, due to some unique physical properties of water and the snow's insulating qualities, the glacier temperature below the surface never falls below 32 degrees Fahrenheit. Therefore, the iceworm may never be confronted with freezing to death because he penetrates deep into the glacier's depth. On the other hand, higher temperatures are harmful to iceworms. When heated to about 40 degrees Fahrenheit, the worms melt and die.

The Latin name given to the iceworm species is reflective of its behavior. Solifugus, or "sun-avoider" appropriately describes this worm. It hides deep in the ice and snow during bright sunny days, emerging as dusk progresses. This is their feeding time. Scientists believe that iceworms feed on snow algae, pollen grains, ice and snow. In turn, iceworms are preyed upon by snow buntings and other birds. Though commonly found in the more porous snow and "solid ice", the iceworms seem to move with ease. It has been theorized that they crawl around the ice crystals that make up the glacier.

Information courtesy of Chugach National Forest

photo of ice worms and a penny to show scale
Ice worm with penny
to show size



Ice Worms are just one of the species that take advantage of the ice for food and habitat. They survive by eating the algae and pollen that grow and fall in the glacier. In the winter, they move down into the glacier and eat the nutrients that have been trapped by forming layers in the ice over several years.

These creatures are unique because they can move between densely packed ice crystals with ease. They use small bristles on the outside of their body, called setae, to grip the ice and pull themselves along. They have been measured moving at 10 feet per hour on the surface of a glacier!