8 Fun Facts About Groundhogs

groundhog surrounded by dry leaves and small plants

Mary Ann McDonald / Getty Images

Groundhogs, or woodchucks, are rodents that are closely related to squirrels. These vegetarian burrow-dwellers have thick fur and can reach a weight of up to 13 pounds and a length of 27 inches. They build complex underground structures where they hibernate after a compulsory feast.

Other animals sometimes reside with the groundhog, or after the impressive burrow has been vacated. Though perhaps best known as the animal that predicts the remaining time before spring, there are many interesting things to learn about these four-legged mammals. From their agile climbing skills to their ability to pack away a pound of food in a sitting, discover the most fascinating facts about groundhogs.

1. Groundhogs Have Many Aliases

Closely related to squirrels, groundhogs are also known as woodchucks, whistle-pigs, forest marmots, and land beavers. The groundhog (Marmota monax) is one of 14 species of marmots, and while most marmots are gregarious and love company, groundhogs are loners.

Groundhogs are the most widespread of all marmots found in North America — their range includes the southeastern U.S. through northern Canada, with some found as far north as southern Alaska.

2. They Are True Hibernators

Groundhog hibernation can last for as long as five months. During this period, groundhogs go into a dormant state — they lose a quarter of their body weight, their body temperature decreases by 60 degrees Fahrenheit, and their heart rate slows to only five or 10 beats per minute. Not all groundhogs experience such a long hibernation, and those that live in the southernmost regions may stay active year-round.

After their months-long hibernation, groundhogs emerge just in time for mating season.

3. They Feast To Survive Winter 

A brown groundhog standing in a grassy field
Shenandoah National Park / Wikimedia Commons / Public Domain

In order to prepare for hibernation, these diurnal feeders feast all summer long on plants. They’re particularly fond of the plants and vegetables found in gardens, and are often considered to be pests. 

During their summer feast, groundhogs eat as much as one pound of food at a time. Along with vegetation, they also eat grubs, grasshoppers, insects, snails, other small animals, and bird eggs.

4. They’re Impressive Builders

Groundhog emerging from snow covered den
BrianEKushner / Getty Images

A groundhog’s burrow can extend up to 50 feet long, with multiple levels, exits, and rooms. They even have separate bathrooms. Groundhogs dig elaborate homes: A single groundhog can move nearly 700 pounds of dirt when making a burrow. They also know how to prevent heat loss — they sometimes block the entrances to their burrows using vegetation. 

Their burrows aren’t good for everyone. Groundhogs sometimes construct their burrows under building foundations, and they can cause damage to farm equipment that inadvertently crosses paths with a burrow.

5. Their Vacant Dens Are Reused 

The elaborate dens built by groundhogs are important for other animals too; red foxes, gray foxes, coyotes, river otters, chipmunks, and weasels often take up residence in homes built by groundhogs.

Sometimes the other animals don’t have to wait until the burrow is vacant. Opossums, raccoons, cottontail rabbits, and skunks sometimes occupy portions of a borrow while the groundhog is hibernating.

6. They Can Climb Trees

groundhog walking along branches in a tree
S.M. Kriebel / Flickr / CC-BY-SA 2.0

While they may not appear particularly agile, groundhogs actually have impressive climbing skills and are quite active. If they can’t get to their burrow quickly enough, their sharp claws come in handy as they are able to climb trees to evade predators.

If they are being pursued and the need arises, groundhogs can also swim to safety, jumping in the water to avoid danger.

7. Their Burrow Led to an Important Discovery

In 1955 the founder of Meadowcroft Rockshelter, Albert Miller, discovered artifacts in a groundhog burrow. An unlikely find, Miller dug further, and kept his discovery under wraps for several years until he obtained the help of archeologist Dr. Jim Adovasio.

After excavating the site and sending materials to the Smithsonian, radiocarbon dating revealed that the artifacts were evidence that the site was inhabited by humans, most likely as a campsite, 19,000 years ago, making it North America’s oldest known location of human habitation.

8. They Have Their Own Holiday 

The shadow of Punxsutawney Phil, the most famous rodent prognosticator, has been considered an informal predictor of weather since 1887. According to the NOAA National Centers for Environmental Information, Phil’s predictions about extended winter or early spring have been accurate 40% of the time between 2010 and 2019.

As much as we’d like to believe that the reason groundhogs reveal themselves on February 2 is to predict the weather, there is actually a very different reason they emerge. Groundhogs exit their winter slumber for mating purposes. Male groundhogs, who want to get a head start on choosing a mate, are the first to exit the burrow. Timing is everything — groundhogs need to reproduce at the right time to give their offspring the best chance of survival.