Signs of Spring 3: Groundhog Day

Almost two years ago (June, 2011) I wrote about the war I had fought with woodchucks over my big field garden. The woodchucks won, and I had to move my tomatoes and beans from the sunny, open field into smaller, shadier plots up close to the house where the vigilance of Kozmo (my dog) could keep the vegetable marauders at bay. Since my surrender I have had increasingly warm feelings for these resourceful rodents and can watch them running about in my field without giving in to the urge to turn Kozmo loose on them.
(Photo: D. Sillman)

I must confess, though, that the premises and rituals of the event that has gone on for the past 123 years in Punxsutawney, PA (which is only 45 miles away from my house!) are very confusing to me. Why here in Western Pennsylvania? Why groundhogs? Why early February? Some of these questions are best answered by historians (or Wikipedia), but from a biological point of view I don’t think that groundhogs are the best choice for a spring predicting animal.

Woodchucks (and there are many synonyms for “woodchuck” including groundhog, whistle pig, marmot, grass rat and earth pig) are true hibernators that spend nearly six months of every year inactive in a grass-lined, underground sleeping chamber. During hibernation a woodchuck breathes about once every six minutes and maintains a body temperature around 38 degrees F. During hibernation a female woodchuck loses just over one third of its body weight while a male loses nearly half of his (possibly due to metabolic demands of sperm production). Hibernation goes on from early November to late March or early April.

So, for real woodchucks, seeing their shadows in February is only possible in a dream (if woodchucks dream, of course).

What would be a better animal to observe to help us make the critical winter/spring prediction that mid-winter demands? The American robin would be a likely candidate. They typically return to Western Pennsylvania in mid February and are an iconic symbol of the ecological renewal of Spring. The honeybee or its native relative the bumblebee would also be good choices, although as I wrote about last week bees can make potentially disastrous, pre-Spring appearances.

For me, though, the animal that would be the best harbinger and predictor of Spring is a species that lives very close to many of us. It is a species that truly resents the cold, wet days of winter and, although they don’t hibernate, spends a great deal of the winter in a semi-active torpor mostly tucked into warm recesses of human-made shelters. These animals actually increase their body weight over the winter but only truly come alive when the warm days of Spring set in.

My new species for our early February winter/spring celebration is the house cat. On February 2, I will take my two cats (Taz and Mazie) out into the front yard (if I can pry them out of the piles of blankets on my bed) and set them down (gently and humanely, of course). If they run back into the house, then we will have six more weeks of winter. If they linger and seem at home out in the yard, then an early Spring is coming!

What will be their cue in their decision process to run or stay? I don’t know, but I am sure that it won’t be their shadows. Cats are well known to have sensory potentials that are at best mysterious to us mere mortals.