Illinois’s 1,473 groundhog records come from every corner of the state, and the calendar behind them tells its own story: reports nearly vanish from November through February, then flood back in March and crest in May.
A true hibernator
That winter silence is genuine. The groundhog is one of the few true hibernators among Illinois mammals, retreating to a plugged burrow chamber where its body temperature and heart rate collapse for months at a stretch. It fuels that fast with a layer of fat built up through late summer grazing, and its reappearance in early spring, when little green food is yet available, is one of the more demanding seasons of its year.
Fields, fencerows, and embankments
The rest of the year, the groundhog is a grazing animal of open ground near cover, feeding on clover, grasses, and garden crops within a short dash of its burrow. It needs deep, workable soil for that burrow, often set into a slope or bank, and Illinois’s farm country supplies the combination generously: Champaign County leads the record, and clusters turn up from Fox Ridge State Park and Cahokia Mounds to the wooded margins of Shawnee National Forest.
Status in Illinois
NatureServe ranks the groundhog S5, Secure, in Illinois, and the species is native across the state. USGS NAS does not list it as nonindigenous here.
