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by Kevin Strauss
Whenever I travel to other states and tell people that I live in Ely, Minnesota, you can see it in their eyes. They are imagining that I have to wear expedition-weight long underwear, a snowmobile suit and snow goggles from November until May. I try to explain to them that it depends on what kind of weather you are used to. While ten degrees below zero sounds frightening to someone from Illinois, it isn’t all that serious up here.
Sometimes I think that wildlife deals with winter the same way: it all depends on what you are used to, and how your body is built for the cold. It is no coincidence that northern Minnesota has no active reptiles and few active insects during the winter. The animals that can handle our cold temperatures and stay active throughout the winter, do it with the “furnace and insulation” approach to winter animal survival. This approach means that animals will try to produce as much body heat as possible by feeding on (relatively) warm winter days, and they will conserve the body heat that they produce by growing thick fur, fluffing their feathers or seeking shelter in spruce trees or fluffy snow.
Wild canines like wolves, coyotes and foxes, not to mention winter-adapted domestic canines like sled dogs, curl up in the snow to conserve body heat, often using their fluffy tails as a scarf to keep their feet and faces warm. By reducing the the surface area of their bodies that is exposed to the air, they stay warmer and make even better use of their thick winter fur.
Speaking of fur, many mammal species have two layers of fur, guard hairs and the undercoat. Guard hairs are long, thin hairs that act like a raincoat. The underfur is shorter and more curly. It is the “long underwear” layer of the fur in wolves, beavers and other northwoods mammals. It is the fluffy “underfur” that our dogs shed out in the spring, when they no longer need it.
Deer and moose carry a different kind of fur adaptation. They simply grow a new coat in the fall that consists of hollow hairs. This thick new coat sheds out in the spring, but during the winter, the hairs act like fiberglass insulation, keeping these ungulates warm.
Birds seem to stay warm by fluffing their feathers, to trap more air (and heat) close to their bodies. If that fails, then the birds just shiver. Some scientists estimate that black-capped chickadees shiver all through the winter. The muscle activity of shivering helps the body generate additional heat. But to keep shivering, a chickadee needs to feed from sunrise to sundown on below zero days to keep their furnaces stoked.
I like to think that wildlife has a lot to teach us about living in the north. So when you are enjoying the outdoors this winter, dress in multiple layers (like beavers), wear a insulating clothes that trap air (like deer and chickadees) and eat hearty meals (like chickadees) so that if all else fails, you can shiver your way back into the waiting car. |