Posted by Janet Harriett on Feb.03, 2010

Photo Credit: Wikimedia Commons User R6MaY89

Yesterday, the groundhogs woke up to tell us whether we get to expect six weeks of winter or an early thaw. Staten Island Chuck, Wiarton Willie and Punxsutawney Phil each offered their weather forecasts for the coming spring, with Chuck coming out for an early spring, without biting the mayor of New York this year, and Willie and Phil both predicting more winter to come.

Groundhogs, (Marmota monax, also known as woodchucks or whistle pigs), are a common rodent that ranges from Alaska south through Canada and the eastern United States. At about a foot and a half to two feet long and weighing up to 9 pounds, they’re about the size of an average house cat, though they have much shorter legs and a broader body than a cat. They’re one of the largest common relatives of the squirrel. Captive groundhogs, like Punxstawney Phil and Staten Island Chuck, and groundhogs that have a large foraging area to themselves, grow somewhat larger than wild woodchucks who face competition for food sources; Phil’s keepers put him at 12 pounds.

Groundhogs live at the edge of woodlands where they have plenty of shelter and burrow space, but can still have plenty of grass forage. They eat primarily succulent plants like grass and clover, though as many gardeners living with groundhogs can attest, a groundhog’s definition of “succulent” often includes many common garden vegetables and orchard fruits.

Much of the garden destruction that groundhogs wreak for backyard veggie patches comes from their late-summer bingeing. From about August through October, just as tomatoes and other garden veggies are hitting their peaks, groundhogs start packing on the pounds to prepare for winter. Groundhogs are one of the few animals that truly hibernate through winter, and they must build up energy reserves to keep them going during the months where the don’t emerge from their burrows or eat anything.

As true hibernators, groundhogs retreat to a burrow excavated below the frost line (usually at least four feet down) and curl up in a ball to wait out the winter. Hibernation is often compared to sleeping, but in hibernation, body functions slow down dramatically and the animal’s body temperature and metabolic rate drops dramatically. Unlike a sleeping animal or one in torpor (“light” hibernation, like with bears), when a groundhog is hibernating, it won’t wake up in response to external stimuli like noises or physical contact. Groundhog hibernation generally starts in October. By the time groundhogs rouse in March or April in response to environmental cues, they have lost about half their pre-hibernating body weight.

Groundhog Day Origins

So how did we get Groundhog Day in February when groundhogs are hibernating through their own holiday?

On a solar calendar, February 2 is a cross-quarter day, about halfway between an equinox and a solstice. Many cultures that originally reckoned seasons by the sun and day length developed traditions and folklore around these cross-quarter days. Weather and the coming spring have been a particular theme around the February 2 cross-quarter day, at least since the Ancient Romans, who had a tradition similar to Groundhog Day using hedgehogs.

One specific bit of cross-quarter weather folklore came from germanic people in the middle ages, who held that if the sun shines on Candlemas (February 2), casting a shadow, winter will hang on for another six weeks. Badgers were the original animal of choice for adjudicating the presence of a shadow. When germanic immigrants settled in Pennsylvania, outside the natural range of North American badgers, the traditional role of the badger got passed to groundhogs, which are similar in size and general shape to badgers, though groundhogs are rodents and badgers are members of the weasel family.

Next week: A look at Groundhog Family Life and Groundhog Trivia

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Posted under Living, Nature and Environment.