Groundhogs are rodent order, in the Sciuridae family. They are one of the largest, and most well known animal diggers in the world. They have several common names, including "whistle pig", "woodchuck", and "land beaver". They are much bigger than their relatives, such as chipmunks and squirrels. Double layers of fur keep them warm and waterproof, enabling them to cope in the cold and wick away moisture after being in the water.
Groundhogs have a wide distribution in North America, especially in the east, being found from Georgia and Alabama in the United States to Ontario and northern Quebec. In the west, they go northward to Alaska and through the Northwest Territories and southern Yukon. Groundhogs like to be in open areas like fields, open forests, clearings, and rocky slopes. They usually establish their burrows where short-growing plants such as luxuriant grasses provide food for them. They generally avoid damp, swampy areas.
Groundhogs are diurnal and solitary non-social animals. The home range of dominant males usually overlap with the ranges of 2 or more females. Subordinate males live a nomadic life. Groundhogs usually build summer and winter dens which typically have several entrances (and an escape hole) with many tunnels and chambers. Groundhogs usually eat twice a day in summer, each feeding session being no longer than 2 hours and they are often seen in the middle of the day sunning themselves. When threatened, they arch their bodies, bare their teeth, and raise their tails. They further communicate via vocalizations and scent glands. Typically, groundhogs are true hibernators, though, in the south of their range, they can remain active all through the year. For certain times of the year, groundhogs may enter torpor in the daytime.
Groundhogs are polygynous, males having multiple mates each season. Males emerge earlier from hibernation than females so that they can establish territories and dominance hierarchies, and search for mates. Mating takes place soon after hibernation in spring, with the exact time varying by latitude and usually extending from early March until mid- or late April. Captive individuals can breed all year round. Gestation is 31 to 32 days, and 1 to 9 offspring are born, the size of most litters being 3 to 5 pups. Weaning takes place around 44 days old. Very quickly pups become independent and leave their mothers around 2 months old. Groundhogs can be sexually mature at the age of 1, however maturity at the age of 2 is more usual.
Currently there are no significant threats to groundhogs.
According to IUCN, groundhog is common and widespread throughout its range but no overall population estimate is available. Currently this species is classified as Least Concern (LC) and its numbers today remain stable.
Burrows abandoned by groundhogs provide shelter for a variety of wildlife including rabbits, raccoons, foxes, weasels, skunks, and opossums. In addition, when groundhogs dig their burrows, they move large amounts of subsoil, which helps with aerating and mixing the soil.