Fern Glen Essays
While you were sleeping
by Judy Sullivan

I love a good argument. Unfailingly romantic, my husband and I are never closer than when debating the etymology and correct usage of specific terms. We nearly kill each other in a race to seize the nearest reference work. Unfortunately, my best efforts couldn't spark any response from him to the word "hibernation," a term over which I've been musing for several days. Ergo, I turn to you.

It should come as no surprise that the word "hibernation," like so many English words, comes from Latin. "Hibernus" means "of winter." I asked my prepubescent neighbor to name an animal that hibernates and his confident response was "a bear." I asked him to name another and, scratching around the blue and green spikes on his head, he shrugged. The problem with this scenario was not the coif, (which in the day between posing the question and writing this sentence has changed to a tasteful shaved skull dyed in a checkerboard motif) but the definition of hibernation. Brace yourself for the shocking news; bears aren't true hibernators.

In order to be classified as a "true" or "deep" hibernator, there needs must be a drastic reduction in metabolism, heart rate and respiration, combined with a body temperature that plummets to just a few degrees above freezing. Our own black bears come close, but don't quite make the hibernation grade. Their metabolism slows significantly and their digestion shuts down to the point where they reabsorb and reuse the limited amount of urine that they do produce. They also form a handy little suppository of feces, hair, and bedding material that blocks the sphincter and keeps them from soiling their sheets (Parents take note of the possible applications here...). However, neither a bear's temperature nor respiration drops by much; and you may find it prudent to recall that they wake easily. I've been regaled with several suspenseful tales of researchers and presumably sleeping bears.

Raccoons, skunks, and opossum bunk in for much of the winter, waking periodically and venturing outside. They, like bears and others, rely on generous deposits of brown fat, criss-crossed with blood vessels, that generates extra heat for kick starting the waking process. The next time that you're out strolling on a chilly day and encounter doting parents pushing a pram containing a mountain of blankets covering a molehill of baby, you can reassure them that their offspring has extra deposits of brown fat around his chest and neck to protect him from the cold. Like many mammals, Junior will lose this extra insulation as he grows.

Chipmunks, of course, have industriously spent the clement months stocking their pantries. Without the benefits of a Rubinesque form to supply their nutritional needs, they wake to nibble and go back to bed. If the larder is running low, they conserve energy and avoid boredom by sleeping. (I would, too.) Hibernation is not so much as a reaction to cold weather as it is avoidance of famine during a time when meals are in short supply.

The author is rudely awakened from torpor by a nosy researcher, only to discover an empty larder. Fortunately, she's stored sufficient fat reserves to last through the winter.

So, just who are the real hibernators? Not bears, apparently. Not frogs or turtles, either, although they bury themselves in mud for the winter. Our great, true hibernators are the common woodchucks. Following closely are bats, which in our area are most often little brown bats. Even deep hibernators wake during the winter. One would just assume that they're simply tired of sleeping (only in my dreams...). Researchers once believed that hibernators needed to wake to obtain nourishment, to "fix" things that had gone wrong in the brain during torpor (sort of like restarting a computer), or that the brain needed to be "exercised." However, all of these are only partially true. The most important reason that hibernators wake up during hibernation is because they're sleep deprived. Would I convey an untruth? Tune in next week for a real eye-opener.

Questions, comments, or other feedback to Judy Sullivan.