Winter Adaptations

 

Sunrise the other day dawned at a brisk -4F (feels like -15F).  And while we have to deal with decisions about venturing outside our process has more to do with is it just taking the dog out to go potty, at we going out for an hour to check trail cameras or is this a trip to town for a scheduled meeting or a gallon of milk or do I have to dress for a Packer game at Lambeau Field.

All of the foregoing involve different sub-decisions about how to layer-up or is the trip even necessary.  How do the resident critters that make their home around here adapt and adjust?

The short answer is that wildlife does have adaptations to the seasons and this time of year they manifest as both physical change, behavior or a combination of the two. 

Thinking of the critters that show-up most frequently on the trail cameras The resident white tails, raccoons, coyotes fox and other mammalian species all grow a thicker coat of hair and fur that absorbs sunlight, and provides camouflage properties avoid detection by predators.  Additionally, this fur coat generally consists of several layers; the softer, thicker layer adjacent to the skin traps air and retains body heat.  Next to this undercoat is an outer layer of guard hairs that repels rain, snow and wind.  

As I observe the dark-eyed juncos scratching in the snow beneath my bird feeders they look like grey on white puff balls.  They also have two layers of feathers to repel the elements and retain body heat.  This effect, related to goose bumps, is called  piloerection and animals puff up their fur or feathers to not only look larger as a defense mechanism; but also as a means of thermoregulation to conserve energy and retain heat.  

In the run-up to winter wild animals consume more calories to build-up stores of fat. This additional fat not only adds an extra layer of insulation it also is a store of energy reserves that can be metabolized during periods of food scarcity. 

Deer and rabbits modulate their circulatory systems (and evolutionary mechanism - not a parlor trick) such that blood vessels found in the ears and other extremities have reduced blood flow helping to retain core body temperature. 

Naturally, many animals (just like many of my neighbors and friends) beat it out of dodge before the Thanksgiving holiday and return with the warmer temperatures and lengthening days of springtime.  The herons, cranes, orioles and many other birds winter in warmer climes along with many of their warm season human neighbors.  

Other animals split the difference.  They don't migrate and they don't recreate; they hunker down to ride-out the winter.  The resident skunks, snakes, muskrats, salamanders, chipmunks, badgers, bears, turtles and other burrowing wildlife retire to their underground dens and enter a state of torpor or hibernation - a state of reduced metabolism where they survive on fat reserves or food caches over the winter season.  While our apex species, the whitetail deer, do not have a location or den; they do regulate their movement during the harshest winter conditions and seek bedding areas in thick conifer cover which provides browse and serves as a windbreak and thermal protection. 

Over millennia native wildlife have evolved and developed adaptations to managing all seasons and living conditions.  It is both remarkable to witness and not so remarkable to understand.  Get yourself a trail camera and situate it within view of a deer trail.  Over the course of a season you can use your citizen science skills to document the changes one animal undergoes as they go through their annual molt.