February 2nd marks Groundhog Day, an annual tradition in which we rouse a sleepy, burrowing rodent to give us winter-weary humans the forecast for spring. Although Punxsutawney Phil does his best as an ambassador for his species, revelers in Gobbler’s Knob and elsewhere likely know little about the true life of a wild groundhog beyond its penchant for vegetable gardens and large burrow entrances. In celebration of the only mammal to have its own holiday, I share with you eight lesser-known facts about groundhogs.
1. Groundhogs, whistlepigs, woodchucks, all names for the same animal. Depending on where you live, you might have heard all three of these names; however, woodchuck is the scientifically accepted common name for the species, Marmota monax. As the first word suggests, the woodchuck is a marmot, a genus comprised of 15 species of medium-sized, ground-dwelling squirrels. Although woodchucks are generally solitary and live in lowland areas, most marmot species live in social groups in mountainous parts of Europe, Asia, and North America.
2. How much wood would a woodchuck chuck? As a biologist who studies woodchucks, this is the number one question I am asked about my study species. To set the record straight, woodchucks do not actually chuck wood! In fact, the name “woodchuck” is actually thought to derive from the Native American word for the animal, not because of the species’ association with wood. Although they may chew or scent mark on woody debris near their burrows, they do not cut down trees (unlike their cousin, the American beaver, Castor canadensis).
3. Woodchucks are the widest-ranging marmot, and are able to adjust to a variety of habitats and climates to survive. Woodchucks are found in wooded edges, agricultural fields, residential gardens, and suburban office parks as far north as Alaska, eastward throughout Canada, and as far south as Alabama and Georgia. The weather extremes of these areas range from subzero winters to scorching summers, thus woodchucks must employ unique physiological strategies to survive. Woodchucks are considered urban-adapters because of their ability to live around humans by taking advantage of anthropogenic food sources such as garden landscaping and managed vegetation.
![Groun[d]hog Day from Gobbler's Knob in Punxsutawney, Pennsylvania." Photo by Anthony Quintano. CC by 2.0 via Wikimedia Commons.](http://blogoup.electricstudiolt.netdna-cdn.com/wp-content/uploads/2015/01/Groundhog_Day_Punxsutawney_2013-2.jpg)
4. Woodchucks are considered the largest true-hibernators. As herbivores, woodchucks have very little to eat during the winter months when most vegetation has died. To save energy during the winter, woodchucks hibernate. The timing of this slowdown is thought to depend partly on photoperiod, which varies by latitude. They generally seek hibernacula under structures or in wooded areas protected from wind. Prior to hibernating, a woodchuck will go in and out of the burrow for a few days to a few weeks, foraging to build up fat stores until entering one last time to plug the burrow entrance behind them with leaves and debris. As a true hibernator, the body temperature of a woodchuck can drop to just a few degrees above that of the burrow, their breathing decreases, and their heart rate slows to around 10 beats per minute. Although they rarely exit the burrow, hibernating woodchucks awake every 10 days or so, hang out in their burrows, and then go back sleep after a few days. The length of the hibernation season can range from just 75 days, to over 175 days, depending on their location. They emerge in early spring, and generally breed soon after.
5. Woodchucks dig complex underground burrow systems, in which they rest, rear young, and escape from predators. If you are a homeowner who has had a woodchuck on your property, you are probably familiar with the large and numerous holes that woodchucks dig in the ground. These many entrances are used as “escape hatches” for a woodchuck to quickly go underground at the first sign of a threat. As escape is their best line of defense, rarely will a woodchuck forage more than 20 meters from a burrow entrance. Underground, burrow systems are comprised of multiple tunnels, some up to 13 meters in length and over 2 meters deep, that lead to multiple chambers, including bedroom chambers, and even a latrine burrow (woodchucks rarely defecate above ground to avoid attracting predators). Based on our research, woodchucks can use up to 25 different burrow systems, likely moving around to avoid predators, look for mates, and find new foraging spots.
6. Woodchucks can swim and climb trees. Although their portly body shape does not suggest agility, woodchucks can move quickly when they really need to. To avoid predators, woodchucks are able to swim short distances across creeks and drainage ditches, and are able to climb trees. They have even been spotted on rooftops and on high branches of mulberry trees, foraging on berries.
7. Woodchucks vocalize. The origin of the name “whistle pig” comes from the high-pitched, loud whistle woodchucks emit when threatened, likely to warn offspring or other adults of an approaching predator. In addition to the whistle, woodchucks will chatter their large incisors as a threatening reminder of the strength of their bite.
8. Woodchucks are easy to observe. My favorite characteristic about woodchucks is that their size (about the size of a house cat) and daytime activity patterns make them easy to observe. Unlike most mammals, you can easily spot them foraging in open fields and roadsides and they generally will tolerate the presence of humans at a distance. If you live in the woodchuck’s native range, keep your eyes peeled for these large squirrels, grab your binoculars, and take a minute to watch them forage and vigilantly observe their environment. It’s a fun way for kids and adults alike to test their skills as a wildlife biologist!
Image Credit: “Groundhog.” Photo by Matt MacGillivray. CC by 2.0 via Flickr.
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