Woodchuck, ground squirrel or ground hog.

The groundhog, also known as a woodchuck, whistle-pig, or land-beaver in some areas, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. Other marmots, such as the yellow-bellied and hoary marmots, live in rocky and mountainous areas, but the groundhog is a lowland creature.