a groundhog (otchig , or otcheck; influenced by wood). or groundhog Reddish brown or brown species (Marmota monax) of solitary marmot inhabiting fields and forest edges in Alaska, Canada, and the eastern and central U.S. Woodchucks are 17-20 in. (42-52 cm) long, have a 4-6-in. (10-15-cm) tail, and weigh 4-14 lbs (2-6 kg). They are good diggers, swimmers, and climbers. Their burrows have a main entrance and an escape tunnel. See also Groundhog Day