
As humans enjoy spring’s warmer weather, we are reminded of extremophiles that can only survive in the cold. They include ice crawlers and ice worms.
Ice crawlers (Grylloblatidae), also known as icebugs, are about an inch (3 cm) long. They are nocturnal, spend the daytime under snow, and then emerge at night to forage for dead insects and plant material blown by the wind. They live under logs and deep in crevasses in warmer weather to stay cold. Ice crawlers have no wings and only diminished eyes. Their optimal living temperature is 34-39 degrees F (1-4 C). Lower or much higher temperatures can kill them. They survive on glaciers and ice sheets.
Ice-worms (Mesenchytraeus), also called glacier worms, survive in glacial ice and eat algae and bacteria that live there. They spend their entire life cycle at 32 degrees F (0 C) or lower and will die if the temperature goes above that. These tiny worms move between the ice crystals using small bristles called setae.
Birds that live in high-altitude snow and ice fields feed on ice worms and ice crawlers. Snow buntings stay in the ice fields year-round, and other birds stop there during migration in the spring and fall.
Many years ago, my daughters and I were on a snowmobile trip in Jasper Provincial Park, Canada. We gazed down into a crevasse and marveled at the beautiful blue color, free of any dirt lines. It was so pure that the ranger guiding us gave us a cup of melted glacial ice to drink. He said a biologist told the park service that the melted glacial ice was safer to drink than distilled water. I questioned that statement, but now we know that ice crawlers and worms do an incredible job of keeping the snow and ice pure. There were birds all around us during that visit, but it was years later before I learned that birds like snow buntings exist.
God’s design of every part of Earth’s biosphere has unique conditions, requiring living things to have special equipment to survive there. The more we see the Earth’s varied environments, the more we see God’s wisdom and creation around us.
— John N. Clayton © 2025
References: Wikipedia “Grylloblattidae” and “Ice Worm”