Groundhog    Marmota monax

The groundhog is also commonly called the woodchuck.  The “celebration” of Groundhog Day, February 2, is actually Woodchuck Day!  Tradition has it that if a woodchuck arouses from hibernation, comes above ground and sees its shadow, it will go back into hibernation for 6 more weeks.  If no shadow is seen, it represents that the weather is rainy or cloudy, and that spring cannot be far behind.  This is certainly not an accurate way to predict the weather, but a good story nonetheless. 
  
Woodchucks utilize a variety of habitats for food and shelter including shrubby or weedy areas, woodland edges, fencerows, railroad embankments, drainage culverts, and agricultural fields.  Woodchucks are rodents, like mice and squirrels, and are driven by the necessity to gnaw and chew on hard objects like shed-off deer antlers and tree bark to keep their teeth in top shape.

Woodchucks live primarily underground in dens, but have winter and summer living arrangements.  A winter den, typically in a wooded area, has a single entrance and a sleeping chamber.  A summer den, however, may have 2 to 5 entrances, several sleeping chambers, hidden entrances, turnaround spots, and blind passages.  Typically the sleeping chambers are at a higher level than the rest of the tunnels, to prevent flooding.

Woodchucks normally feed and are active during daylight hours, but even during their most active time of the year, they are above ground only 1 to 2 hours a day.  They remain very close to the den entrance, only travelling short distances to forage for food along established paths.

Woodchucks are true hibernators, and during the winter months, their body processes almost completely shut down.  In their underground den, their breathing and heart rate slow down, body temperature drops significantly, and even teeth and claws stop growing.