Although many species migrate to warmer climes during our frigid months, other familiar species remain for the duration, utilizing a variety of strategies for survival.
Amphibians in particular, cold-blooded animals that take on the ambient temperature, have some ingenious methods of lasting out the cold. Some frogs and toads hibernate in the mud at the bottoms of lakes or inside logs or under leaf litter (a good reason for leaving some leaves in the fall). Some toads bury themselves deep in the earth to brumate, i.e., to slow down bodily functions.
Researchers report that our wood frogs spend the winter frozen for up to eight months! The spaces between organs become ice crystals, while the vital organs are filled with a sugary, syrupy fluid created by the liver, which acts as an antifreeze. There is no muscle movement, no heartbeat, no breathing. “It becomes a frozen stone seemingly carved in the shape of a frog.” Actually, it is in a state of suspended animation. In spring, it thaws from the inside out. The heart begins to beat, the brain functions, and the legs move. Once fully thawed, it heads right to the nearest evanescent vernal pool or other body of water, to begin the breeding process.
We humans could learn from these creatures, as they are able to sustain so much sugar in their systems, unlike diabetics. Learning to freeze organs would assist in transporting organs for transplants, and thawing them without damage. And it would be useful to know how blood begins to flow without creating dangerous clots, especially for heart attack and stroke patients.
Once I had the good fortune to be at a vernal pool on the exact right day when the amphibians were in a mating frenzy. The males puffed out large throat pouches, to sing deafening calls to attract females. Apparently, in their heightened state, some males jump on other males, until the beleaguered frog utters a loud cry and escapes. Groups of males may jump on a lone female, waiting to see which will fertilize the long stream of thousands of eggs which she lays in the water.
Bernd Heinrich, renowned nature researcher, has described a variety of cold weather coping strategies. Grouse bury themselves in the snow. Many birds eat protein-rich foods in breeding season but now seek seeds which are high in oils and fats for warmth. Feathers fluff out to trap air between them. Chickadees go into torpor at night. They are well adapted to survive, as their feet remain at 30 degrees, but the body temperature remains at a necessary 105 degrees. Others utilize tree holes, or, like bluebirds, huddle together for warmth, sometimes switching places so each bird has an equal opportunity for warmth.
With our extremes of weather, from -12 to 60 degrees, we are happy to get out into this nearby wildness in the city, which we crave. Ice formations crackle at the edges of coves and rivers, and there are bands of ice and areas of open water made wavy by wind. Seagulls fly up, backlit wings aglow, reminiscent of Jonathan Livingston Seagull. An exquisite, alive sight, a delight to behold.
At the edge of a cove, sparrows are fluffed to the max, fly hither and yon in a stand of trees, pecking at the bark for seeds. Very much alive, after surviving that Arctic chill, probably huddled together on a bushy evergreen. This miracle brings to mind the Biblical psalm, as well as the 1906 hymn based on it. “His eye is on the sparrow”: even the tiniest of creatures is protected, not overlooked.
A wind picks up out of nowhere, oak leaves fluttering and flying across the road, like birds, dipping and twirling. Out on the river, in the live water, a male swan patrols his territory in threat mode, wings lifted elegantly, the female lackadaisically foraging among dozens of geese.
In a cove, two swans act as one, close together, dipping heads in the live water on this warm day, in perfect synchrony. They separate, and he moves on top of her for a brief interlude, as she sinks down! Mating in February! They proceed to face one another, bill to bill, their necks forming a perfect heart shape, a romantic end to this encounter on the eve of Valentine’s Day.