Surviving the Deep Freeze

Surviving the Deep Freeze
January 25 & January 27

One of the several slide show/Power Point presentations that I enjoy showing to interested groups in the Quinte area, and beyond, is one titled, “Preparing for the Big Freeze.” Other than a presentation I continue to show on a Rideau Canal kayak trip I took three years ago, it is probably one of my favourite presentations since it is a delight to present and was a lot of fun to put together.
One of the pleasures derived from creating a new presentation, is the process of learning new information, and sharing that with audiences. Repeating some of this trivia on guided hikes tends to lock it forever in memory, where it can be recalled when needed.
Surviving the big freeze. Beyond the commonly known bird migration and animal hibernation, are some incredibly ingenious methods that have evolved over time. How insects actually manufacture a sort of antifreeze to prevent vital organs from succumbing to the cold, and the eggs of one insect in particular cleverly encased in a capsule that looks like, and functions, like Styrofoam.
We learn in the presentation, for example, that not as many mammals hibernate as we might think. Not even bears, who do become active occasionally in the winter, but slumber some of the winter away in a bit of torpor when the internal body temperature doesn’t really drop that much. Compare that to one of the hibernators, the chipmunk, whose heartbeat drops from 350 beats per minute, to just four, barely enough to keep it alive, and its body temperature plummets from 37 degrees to just three degrees. That’s true hibernation. A chipmunk can spend the entire winter in this death-like trance, but may awaken every two weeks or so to nibble on its cache of nuts and seeds collected in the fall. It also takes this opportunity to do its toilet, before pulling the covers up around it again for another two weeks.
For other mammals, it’s business as usual. The occasional smell of skunk in the winter verifies that these mammals are out and about. Similarly, raccoons, foxes and a host of others. But they do prepare, to some extent. Deer, for example shed their short summer hair in the fall and grow longer hair. But it’s more complex than that. The hair of deer in the winter are hollow and filled with air that acts as insulation. They also shiver, like us, causing this hair to stand upright, trapping even more insulating air.
Foxes and coyotes that are busy looking for prey, develop extra hair around the feet to assist them in deep snow, but also insulating them as well. In addition to adaptation, camouflage plays an important role in a mammal’s ability to survive. The snowshoe hares that we find every winter at the Frink Centre at Plainfield, change their colour to white once winter arrives, making it more difficult for predators to locate them. They must also learn to change their diet, from one of leaves and herbaceous plants, to that of tender twigs and the bark of saplings. Deer, too, change colour, somewhat, to a greyish winter coat, allowing them to blend in with the dull winter background.
Small meadow voles (field mice to most of us) who burn energy quickly, tend to stay beneath the snow, their intricate labyrinths quite visible after a fresh snowfall, as they feed on grasses and seeds they find ahead of them. Any voles that don’t survive, are eagerly consumed by shrews that follow along behind. It’s a dog eat dog world out there, and a life of adapt or die. Winter is Nature’s time to purge the population of the old, the sick, the weak, the deformed and the less intelligent, leaving only the fittest and most educated to reproduce in the spring.
However, among these mammals who remain more or less active in the winter, are those that do truly hibernate. The woodchuck or groundhog is our best known, but bats also go into a deep sleep, seeking out caves, buildings and, yes, attics, to spend the winter. And they manage to survive, living off their fat reserves, until warm weather brings them out of their hibernation. It is only when a well meaning person finds one tucked in behind a loose board somewhere, and attempts to relocate it, that the bat is doomed, for once disturbed, valuable fat reserves are used up that would otherwise take it through the winter.
Unlike meadow voles who have evolved short extremities to prevent heat loss, jumping mice with their long tails and long hind legs cannot afford the luxury of losing heat through remaining active all winter, so they, too, hibernate. Of course, squirrels we know about, especially those of us who maintain feeding stations. They remain quite active, but do make a few changes in their lifestyle, leaving their airy and leafy tree nests, and seeking refuge in hollow trees or under stumps, out of the weather. During the day they eat peanuts and sunflower seed at our feeders.
Winter survival is a fascinating routine that all species at this latitude have manage to perfect over the centuries. We don’t usually give it much thought; we just know that in most winters, it seems to work.