Naturalist Corner: A Mouse’s Winter Journey

Beneath the Snow: A Mouse’s Winter Journey

Above me, the snowdrifts tower high, their icy edges cutting into the sky. The wind howls above, but it is muffled down here, beneath the thick blanket of snow. In the Subnivean Zone, the world is a different place between the warmth of the earth and the sheltering snow above.

As the first layer of snow falls each year, hardy plants, woody debris, and rocks create natural umbrellas for small creatures like me. I am thankful for the fallen timber and vegetation that suspends the snow from the ground and creates my winter refuge. These layers of snow act as our roof—thick enough to keep us warm and sturdy enough so we can move freely beneath.

I scurry along the tunnel I’ve dug, the earth and snow around me forming a sturdy, insulated shell. The tunnels crisscross through the snow like veins in a living creature. Each tunnel leads to a different room: my sleeping quarters, food cache, and latrine. The air down here stays fresh because I’ve left tiny shafts open to circulate air from the surface. My system of tunnels and rooms is all connected in a perfect maze for survival.

I am dreaming about the Spongy Moth larvae I will consume come spring. Right now, if I’m lucky, I’ll find pockets of fresh greenery or other caterpillar eggs to eat. The snowpack is my defense, making it harder for predators like owls or foxes to reach me. The predators that hunt us above can still hear the slightest movements beneath. Owls can track us from thirty yards away with their keen sense of hearing. A sharp dive, and they’re through the snow, snatching us up before we can react. Foxes and coyotes use their sharp sense of smell to locate us before pouncing through the snow to grab us. And then there’s the ermine—a white weasel that slides effortlessly down our air shafts, bold and silent. It comes without warning, filling up on our kind and sometimes making our tunnels its own.

The shrews, small and ferocious, prowl these same tunnels, always hungry. They don’t really care for seeds or roots like I do; they mainly hunt insects, larvae, and even small mice like me if we’re unlucky. Their appetite is insatiable—they need to eat the equivalent of their body weight every day to stay alive. We don’t cross paths often, but when we do, we are wary. The shrews are small, but they are swift, and their sharp teeth can tear through flesh in an instant. I keep to my tunnels, hoping they fill up on insects or voles instead.