January Kids’ Corner
from the Gale River Cooperative Preschool
Cozy Critters
As we turn up the heat inside and bundle up to go outside, you may wonder about how animals stay warm in the winter? There are a lot of adaptations they use but one is the use of a unique habitat that only forms during snowy winters. As the snow piles up on the ground, smaller mammals and animals create tunnels underneath the snow. This area is called the subnivean zone.
The subnivean zone forms as we get some good snow accumulation. Most entrances start around the base of trees where the snow depth is lower thanks to the branches blocking it like an umbrella. Once animals get access to the space between the earth and the snow, they can start to build tunnels and rooms including a space to store food, sleep, and relieve themselves. They don’t have to dig it all out by themselves though! The earth itself helps create space through the process of sublimation. This process is when snow goes straight to a gas instead of first becoming a liquid. The warmth from the earth turns the snow into water vapor that rises and freezes again, becoming a sturdy roof for the tunnels. The best part about this hidden habitat is that it stays relatively warm! While the wind and air temperature above the snow can go far below freezing, the snowpack insulates the subnivean zone, keeping it right around 32 degrees. For the furry mammals that use this space, that’s perfect. As an added bonus, it’s hard for predators to find them!
Unfortunately, this hidden habitat is becoming less frequent as our winters warm and we have less snow or periods of thaw and rain mid-winter. If we get more snow this winter, you can try to find a subnivean tunnel system yourself by finding a tree well or air vent holes and digging down to where the snow meets the earth.
Want tips on how to explore subnivean zones this winter? Read below for ideas then head
Outside!
Searching for clues as to where a subnivean tunnel system may be is the best place to start looking for one. Most tunnel systems start around the base of a tree so look for holes in tree wells. You can also search for air vents or other holes in the snow. When you find them, dig down to see if you can find any tunnels along the earth’s surface!
Playing with the process of the changing states of water can be a great way to see how the subnivean zones are created. How can you melt snow or ice quickly vs. slowly? Try using salt on ice to see how it melts. Heat up some water to watch as it changes to a gas. Use a spray bottle on snow to see how the mist impacts the snow.
There are some wonderful books that talk about the subnivean zone. A great one is “Over and Under the Snow” by Kate Messner, illustrated by Christpher Silas Neal, which follows a young girl as she journeys around a winter forest to see who is living above and below the snow. You can read this with your children and use a blanket to have them go over or under the snow as you find where different animals live!
Try building a subnivean zone for yourself! You could use snow to build a maze and send some toy animals through. Can you build a food room, a sleeping room and a bathroom? What would go in those rooms?
