Marmota monax
woodchuck

Marmota monax is the most widespread North American marmot species. The southern limits of its range extend from eastern Oklahoma, northern Louisiana, Alabama, and Georgia to North Carolina. The eastern limits of its range extend from North Carolina, along the Atlantic coast, to Labrador, Canada. It's northern limits range from Labrador to southern Alaska. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kays and Wilson, 2002; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Marmota monax has a wide geographic range and inhabits many different ecosystems. It is typically found in low elevation forests, small woodlots, fields, pastures, and hedgerows. Human activities (e.g., clearing forests, building roads, and agriculture) have increased food access and abundance allowing M. monax to thrive. It constructs dens in well drained soils, and most have summer (located near food sources) and winter (located near protective cover) dens. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks are stocky in appearance and often stand up on their hind legs, making them look tall. Their pelage varies greatly in color but ranges from gray to cinnamon to dark brown. Their body is covered with white-tipped guard hairs giving them a grizzled appearance. Their paws vary in color from a typical black to dark brown in most subspecies. However, one subspecies has paws that appear pink. Their short bushy tail is often black to dark brown and is 20 to 25% their total body length. They weigh from 2 to 6 kg, range from 415 to 675 mm in total length, and have tails that range from 100 to 160 mm in length. Although males and females are the same color, males are larger than females. Woodchucks have white teeth, which is uncharacteristic of rodents, and a dental formula of 1/1, 0/0, 2/1, 3/3, for a total of 22 teeth. They have rounded ears that can cover the external auditory canal which prevents dirt from entering the ear canal while burrowing. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kays and Wilson, 2002; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks live 4 to 6 years in the wild but, due to predation and disease, often do not live past age 3. Woodchucks may live up to 10 years in captivity. (Forsyth, 1985; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks are diurnal, solitary animals. Dominant males have home ranges of approximately 10,000 m^2, which usually overlaps with those of at least 2 other females. Subordinate males are nomadic. Females have a home range of about 2,500 m^2 in the spring, which expands to greater than 10,000 m^2 after giving birth. Woodchucks are burrowing mammals and generally construct summer and winter dens. These dens generally have several entrances (including an escape hole) and many chambers and tunnels. Woodchucks usually feed twice daily during the summer, with each feeding session lasting no more than 2 hours. They are often found sunning themselves in the middle of the day during summer. Although usually asocial, woodchucks will sometimes greet each other nose to nose. Woodchucks threatened by conspecifics respond by arching their bodies, baring their teeth, and raising their tail. They also communicate via scent glands and vocalizations. Generally, woodchucks are true hibernators; however, in the southern part of their range, they have been known to stay active throughout the year. Woodchucks mate soon after emerging from hibernation. During certain parts of the year, they may enter torpor during the day. (Andromeda Oxford and Ltd, 2001; Encyclopaedia Britannica and Inc., 2007; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998; Yahner, 2001)

Home Range

Woodchuck home ranges vary throughout their geographic range. However, evidence suggests that home ranges are approximately 10,000 m^2 for males and 2,500 m^2 for females, prior to parturition. (Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks are territorial and non-social. Sight, smell, and sound are important for communication among conspecifics. Secretions from facial and anal glands are used to demarcate territorial boundaries. They also hiss, growl, shriek, whistle, teeth-chatter, and bark. Woodchucks use their sight to detect predators and to make visual threats to other conspecifics. Vocal threats, visual threats, and fighting are used to establish social rank. (Forsyth, 1985; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks are diurnal and their feeding activity is highest during morning and afternoon. Foraging bouts last less than 2 hours. Preferred forage includes alfalfa (Medicago sativa), clover (Genus: Trifolium), and dandelion (Taraxacum officinale). Other foods include bark, leaves, insects, and bird eggs. All woodchucks store fat for winter hibernation. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks avoid predators by climbing trees and looking up periodically while feeding. Their large body size may deters some predators. They often use their teeth to defend themselves and produce a shrill whistle when threatened. Whistles also serve as a warning call to conspecifics, especially juveniles. Young woodchucks hide in and around the den for protection from potential predators. Known predators include gray wolves (Canis lupus), coyotes (Canis latrans), domestic dogs (Canis familiaris), red foxes (Vulpes vulpes), gray foxes (Urocyon cinereoargenteus), black bears (Ursus americanus), lynx (Lynx canadensis), bobcats (Lynx rufus), hawks (Accipitridae), and snakes (Serpentes). (Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Abandoned woodchuck dens are used by a number of different species, including rabbits, skunks, raccoons, opossums, foxes, weasels, ground squirrels, river otters, chipmunks, meadow voles, short-tailed shrews, house mice, pine voles, white-footed mice, lizards, snakes, and arthropods. They are also host to a number of different parasite species, including botflies, nematodes, protozoa, tularemia, rabies, chiggers, mites, ticks, fleas, and lice. Woodchucks are also prey for many predators species. (Kwiencinski, 1998; Whitaker et al., 1998)

Marmota monax is known to destroy gardens, pastures, and agricultural crops. Their burrows have been known to injure livestock and damage farm equipment and building foundations. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998)

Woodchucks have been used in biomedical research investigating hepatitis B, metabolic function, obesity, energy balance, the endocrine system, reproduction, neurology, cardiovascular disease, cerebrovascular disease, and neoplastic disease. Additionally, they are often targeted as game by hunters. (Grzimek, 2003; Kwiencinski, 1998; Whitaker et al., 1998)

Due to their abundance and broad geographic range, woodchucks are listed as a species of least concern on the IUCN Red List of Threatened Species.

Woodchucks have numerous common names, including ground hog, and whistle pig. The word "woodchuck" is a misinterpretation of their Native American name "wuchak", which roughly translates as "the digger". Groundhog Day occurs when Punxsutawney Phil, a captive woodchuck held in rural Pennsylvania, is awakened from hibernation in order to determine if he will see his shadow. According to the legend, if he sees his shadow there will be 6 additional weeks of winter. If he does not see his shadow, legend predicts an early spring. The legend of Groundhog Day is likely due to the fact that woodchucks often re-enter hibernation after emerging from their dens prematurely. (Encyclopaedia Britannica and Inc., 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker et al., 1998; Yahner, 2001)