WHAT IS A GROUNDHOG?

by Whit Gibbons

February 1, 2015

So is cold weather nearly over for the year or can we expect six more weeks of winter? On February 2, known to most as Groundhog Day, Pennsylvania's Punxsutawney Phil will give his answer. Don't try to figure out why winter should continue for exactly six weeks or end more quickly, just enjoy the tradition. And certainly don't try to make any sense out of the notion that a giant rodent that lives in a hole in the ground and comes out to look for its shadow in February would be any better at predicting the weather than the weather app on your smartphone.

Though a discussion of winter weather prognostication, a centuries-old tradition, would be interesting, a look at groundhog ecology seems more suitable for an environmental column. A recently published book ("Mammals of Alabama," 2014, University of Alabama Press) by Troy L. Best and Julian L. Dusi answers the ecological questions people might ask. Because Alabama has such a high diversity of native mammals, the book covers the biology of most mammal species in the country, especially for the eastern states. A map shows the geographic range of groundhogs: from Alaska, across southern Canada and the northern states, to New England and southward to most of the Southeast.

Groundhogs, also known as woodchucks or whistle pigs, are rodents in the squirrel family. The family also includes chipmunks, tree squirrels and flying squirrels. Groundhogs are in a group known as marmots, their closest relatives being yellow-bellied marmots (rock chucks) in western states. Like other rodents, groundhogs have two upper and lower incisors in the front of the mouth but no canines. The powerful front teeth can gnaw through any type of plant material, including bark, roots and hard-shelled nuts. Their teeth grow throughout their lives. Without constant gnawing to keep them trimmed back, they would become longer and longer.

According to the book, groundhogs "are vocal animals and may squeal, chatter, bark, or give a loud, shrill whistle." If an animal feels threatened by a predator in the vicinity, the whistle presumably serves as an alarm system for other members of its immediate family. A groundhog will typically head for one of the holes leading into a burrow, which can serve as protection not only from predators but also from wildfires and inclement weather. Burrows often have 10 or more entrances on the surface.

Groundhogs are true hibernators. Prior to winter they store body fat and do not eat until they emerge in early spring. Based on their diet, they can be considered to be primarily a combination of herbivore and insectivore. They eat nuts, leaves and other vegetation and a variety of insects. They also eat snails (gastropods). Males will fight in the springtime during mating season. Although groundhogs are the biggest members of the squirrel family in the eastern United States, they have no problem climbing a tree, whether to forage or to use a high perch as a lookout post. They can swim if necessary to escape a predator.

As for the groundhog's physical appearance, most people would agree that whistle pigs, especially the roly-poly babies, would easily qualify as cute. But a wild one would undoubtedly let you know with a solid bite that it did not want to be picked up. Besides the threat from their big front teeth, another reason not to pick up groundhogs is that they can contract rabies, although I do not know of any documented case of transmission to people. A squirrel on steroids might be entertaining to have around, but vegetable-eating groundhogs are not popular with home gardeners, and groundhog burrow openings can be a problem for a horse that steps into one.

If you are unconvinced that a hibernating rodent can signal whether it's time to put away your winter coat, rest assured you are not alone. Not everyone believes Punxsutawney Phil can really predict whether winter will continue for another six weeks. You might as well rely on the Farmers' Almanac.

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