Groundhogs: Illinois’s Largest Squirrel

Groundhogs (Marmota monax), also knowns as woodchucks and whistle pigs, are the largest member of the squirrel family in Illinois. While they can climb trees like their cousins the gray and fox squirrels, groundhogs spend almost all their life at or below ground level. They live in burrows they excavate which generally have multiple entrances, easily identified by the large mounds of earth that are piled up near the entrances. Generally, there will be at least one entrance that does not have the telltale mound of dirt. Excavated from the inside out, this entrance serves as a “bolt hole” and generally is used only in emergencies. Inside of these burrows there will be at least one nesting chamber and a latrine chamber.

Groundhogs are true hibernators, with drastic reductions in levels of physical activity and bodily functions. Leaving their summer burrows in October and November they move to winter burrows to hibernate. These burrows differ by not having the telltale mounds of dirt at the entrance and usually are located in more secluded spots. Beginning in late February and March, depending on the weather, groundhogs will begin coming out of hibernation. This is not so they can predict the weather, as folklore would suggest, but rather to find food as they will have lost a large portion of their body weight during hibernation, and to find a mate for the year. The breeding season is the only time two adult groundhogs will occupy the same burrow. Generally solitary animals, groundhogs prefer to live alone in their own home territory. Groundhogs usually have one litter per year that averages four or five young born in April.

When a groundhog dies or moves to another territory their abandoned burrows do not go to waste. They provide shelter and homes for a variety of wildlife, including rabbits, skunks, foxes and coyotes. Their excavations also aerate the soil.

Groundhogs get the name whistle pig from the shrill whistle that they sometimes make to warn of danger.

Groundhogs occupy a variety of habitats within Illinois but rarely are found living in the floodplain. Most can be found in crop fields, pastures with woody edges, fencerows, and road right of ways. Groundhogs are herbivores and have been scorned by generations of farmers for eating crops and garden vegetables. With the changes in Illinois agriculture, primarily the creation of large tracts of single crop fields and removal of fencerows and pastures, groundhogs usually can be found living in proximity of human development. They burrow under sheds and buildings which can cause structural issues and have been labeled by some as a nuisance animal in suburban and urban areas.

Groundhogs are listed as a game species in Illinois. Consult with the annual Illinois Digest of Hunting and Trapping Regulations for season dates and legal methods of harvesting groundhogs. Groundhogs are one of a few species that can be trapped or hunted. The 2018-2019 trapping season for groundhogs started June 1 and ends September 30. Hunting season for groundhogs starts June 1 and runs through March 31 (closed during firearm deer seasons) and there is no limit.

Many consider the groundhog to be a culinary delight, especially those animals that have fed almost exclusively on garden vegetables. Online resources describe how to prepare a groundhog for cooking and offer a variety of recipes.

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Ben Funk is a Hunter Heritage/District Wildlife Biologist for the Illinois Department of Natural Resources and is stationed at Horseshoe Lake State Park in Granite City.