The groundhog (Marmota monax), also known as a woodchuck, or whistlepig, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. The groundhog has also been referred to as: Chuck, Wood-shock, Groundpig, Whistler, Thickwood Badger, Canada Marmot, Monax, Moonack, Weenusk, and the Red Monk.