It's cold out. Winter's icy grip on the northland, full on, isn't showing signs of release anytime soon.
Cracking trees deep in the forest, popping like rifle shots in the still-night air, along with the sounds of groaning and expanding ice across all of the north country's lakes, are reminders to we mortal humans that furnaces and fireplaces must not fail, and that resident fish and wildlife must call upon stored reserves and a host of other mechanisms in order to survive.
That wildlife can survive at all in such harsh conditions is testament to any living creature, be they swimming beneath sheets of ice, huddled together inside a woodpecker hole high in a maple tree at nighttime, or within the confines of a cozy burrow below the frost-line in deep states of hibernation.
Indeed, wildlife have adapted to Minnesota's extremes in ways that astonish and defy comprehension.
How is it, then, that the American black bear, an extremely active mammal throughout half of Minnesota's calendar year, becomes almost completely immobile and lethargic the other half of the year? Mother Nature, the ultimate driver, guides the bear through instinct, physiology, natural selection, and evolution.
With her guidance the species persists, survives, reproduces and continues its own existence, and that, in order to survive, eating as much throughout the season-of-plenty and living off stored fat reserves in a physiological shut-down of torpor, hibernation became the mechanism and key to survival.
Hibernation and torpor is a physiological and perhaps not completely understood marvel employed by a number of creatures in the natural world.
I'm mystified that birds as diminutive as black-capped chickadees seem to relish winter the way they do. How is it that such a seemingly fragile bird is able to withstand the coldest of winter days, let alone the much colder nights?
Have you ever had a chickadee land on the naked palm of your hand and felt their frigid feet and feeble weightlessness? If you have, then you must have wondered how such creatures can withstand Old Man Winter's onslaught.
They, like the black bear, are able to enter states of torpor, whereby metabolic needs and heart rates decrease, which of course is physiological. Meanwhile, behaviorally speaking, these tiny titans often seek shelter inside tree cavities, either alone or with several other like-minded chickadees, in order to take advantage of neighborly body heat in small fluffy huddles of feathered friends.
Ruffed grouse, and prairie grouse such as prairie chickens and sharp-tailed grouse, have a few tricks up their feathered sleeves, too.
These birds, especially ruffed grouse, have somehow learned through their species' evolutionary journeys to burrow into snow for thwarting the coldest of nights and the harshest of storms. Called snow roosts, these burrows beneath the snow are accomplished by flying headlong into snowdrifts and snowpack to escape the cold.
During the coldest of days and nights, the temperature within a blanket of overhead snow can be as much as 50 degrees warmer than the ambient air temp. Coupled with a grouse's perfectly plumaged bodies, a grouse is never in danger of dying from hypothermia if the right snow conditions exist.
Deer, too, are survivalists of the extreme. These amazing animals, though unable to hibernate or make shelters of their own, use an array of strategies to survive winter. Energetic needs are diminished in the wintertime, which is a good thing since food is limited. A deer's metabolic rate decreases, too, thereby requiring less energy (food).
Fat reserves also help provide needed nourishment during lean times. Their winter coat, a miracle in its own right, is an entirely different coat in the winter from that of a summertime coat. The hairs are thick and hollow and trap air for added insulation. Very little body heat escapes a deer's coat, which becomes evident if one has ever seen a bedded deer with freshly fallen snow laying across its back like a blanket. You will note that the snow doesn't melt. The deer is warm, dry, and comfortable. And likely completely content while chewing its cud.
Wildlife everywhere throughout Minnesota are engaged in a battle of survival that only the strong will see through. Driven by forces that they might be unaware of, northern latitude species are without a doubt creatures to appreciate, as we get out and enjoy the great outdoors.