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.

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range extends from central Alaska eastward across Canada south of treeline to Labrador, and south in eastern North America to Georgia, Alabama, Louisiana, and Arkansas; in the west the species is absent from the Great Plains and ranges southward only to northern Idaho (Kwiecinski 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.

Range mass: 2 to 6 kg.

Range length: 415 to 675 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Average basal metabolic rate: 3.696 W.

Length: 82 cm

Weight: 6400 grams

Short tail, 20-25% of body length (25% or greater in other marmots); head without white markings, except around nose, that are present in other marmots; sides of neck are concolorous with upperparts (buffy in M. FLAVIVENTRIS); forelegs overlaid with deep reddish brown hairs; feet blackish brown; upper tooth rows are parallel (diverging in other marmots) (Kwiecinski 1998).

• Terrestrial

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.

Range elevation: low elevation (low) m.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: savanna or grassland ; forest

Other Habitat Features: suburban ; agricultural ; riparian

Comments: Woodchucks live in open habitats (meadows, pastures, old fields, orchards) that often border wooded areas, which may be used for hibernation (Caire et al. 1989, Kwiecinski 1998). In Connecticut, burrow systems were often along woodland edges and brushy fence rows (Swihart 1992). Young are born in a den in an extensive burrow system.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Connecticut, post-breeding-season adults occupying home ranges used an average of 8 burrow systems; home range averaged about 4 ha in males, 2 ha in females (Swihart 1992). In Quebec and Iowa, home range was 7.8 ha and 4.1 ha, respectively, for males, smaller in females (see Swihart 1992). Females in Ohio had small home ranges (0.25 ha) after emergence from hibernation, but expanded them (to an average 1.35 ha) following after birth of young (Meier 1992). All juveniles disperse, but some remain in natal home range for one year (Kwiecinski 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.

Animal Foods: eggs; insects; mollusks

Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; flowers

Primary Diet: herbivore (Folivore )

Comments: Consumes a wide variety of herbs, grasses, and the leaves of shrubs; also invertebrates (Hamilton 1934, Arsenault and Romig 1985, Kwiecinski 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.

Ecosystem Impact: disperses seeds; creates habitat; soil aeration

Commensal/Parasitic Species:

• botfly (Oestridae)
• nematodes (Nematoda)
• protozoa (Protista)
• tularemia (Francisella tularensis)
• rabies (Lyssavirus)
• chiggers and mites (Trombiculidae)
• ticks (Acarina)
• fleas (Siphonaptera)
• lice (Phthiraptera)

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).

Known Predators:

• gray wolf (Canis lupus)
• coyote (Canis latrans)
• domestic dog (Canis familiaris)
• red fox (Vulpes vulpes)
• gray fox (Urocyon cinereoargenteus)
• black bear (Ursus americanus)
• lynx (Lynx canadensis)
• bobcat (Lynx rufus)
• hawks (Accipitridae)
• snakes (Serpentes)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

10,000 to >1,000,000 individuals

Densities are highly variable, ranging from 0.1/hectare in Quebec to 3.3./hectare in Ohio (Kwiecinski 1998).

Primarily solitary, except during breeding, though limited social interaction may occur at other times.

Abandoned burrows are widely used as den sites by other animals (Kwiecinski 1998).

Woodchucks lose about 33-40% of their body mass during hibernation. Most of the loss occurs when they arouse and warm up every week or two.

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.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Comments: Woodchucks emerge from hibernation in winter or early spring, depending on location. The earliest emergence occurs in the southern part of the range; in the north, woodchucks generally emerge much later than "groundhog day" (February 2)..

Daily activity may vary seasonally. Most activity occurs in early morning and late afternoon; sometimes woodchucks are active at night (Koprowski 1987).

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.

Range lifespan

Status: wild: 2 to 6 years.

Range lifespan

Status: captivity: 10 (high) years.

Typical lifespan

Status: wild: 4 to 6 years.

Average lifespan

Status: captivity: 14 years.

Woodchucks are polygynous, with males having multiple mates per season. Male woodchucks emerge from hibernation earlier than females in order to establish territories, dominance hierarchies, and to search for mates. Older, more dominant males hold territories whereas younger males are nomadic. With the exception of mating season, woodchucks are non-social, and during breeding season, male-female interactions are limited to copulation. Females are monoestrous and mating occurs only during the spring.

Mating System: polygynous

Breeding occurs shortly after emergence from hibernation in the spring, although the exact time varies by latitude. Female woodchucks give birth to 1 to 9 offspring, with most litters ranging between 3 and 5 pups. Pups weigh between 26 and 27 grams upon birth. Gestation lasts from 31 to 32 days and weaning occurs around 44 days old. Pups become independent very quickly and leave the mother around age 2 months old. Some woodchucks become sexually mature at 1 year old, however, they often have a lower pregnancy rate than others. Typically, woodchucks become sexually mature by age 2. Breeding in captive individuals can occur year round.

Breeding interval: Woodchucks breed once yearly

Breeding season: Mating occurs between February and May depending on latitude

Range number of offspring: 1 to 9.

Range gestation period: 31 to 32 days.

Range birth mass: 26 to 27 g.

Average weaning age: 44 days.

Average time to independence: 2 months.

Range age at sexual or reproductive maturity (female): 1 to 2 years.

Range age at sexual or reproductive maturity (male): 1 to 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); induced ovulation ; fertilization ; viviparous

Average number of offspring: 4.5.

Following birth, females provide all of the care for woodchuck pups. Pups nurse for approximately 44 days and become independent at around 2 months of age. Occasionally, females inherit their mothers den. Pups use the den for protection while the mother is away.

Parental Investment: altricial ; female parental care ; pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); inherits maternal/paternal territory

Mating takes place right after emergence from hibernation, often early March to mid-April. Gestation lasts 31-32 days. Young are born from April to mid-May. Juveniles, about a month old, emerge from burrows in spring, and activity ends in fall, the exact timing varying with location (shorter active season in the north than in the south). Reproductive females produce a single litter of 2-6 (average 4) each year. Individuals become sexually mature in one year.

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.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Distributed across much of northern and eastern North America.

Management Requirements: Dolbeer et al. (1991) tested the efficacy of gas cartridges to kill woodchucks in burrows and found them to be effective; however, overall reduction of a population may be difficult due to enhanced survival and reproduction of remaining woodchucks and rapid recolonization from surrounding areas. The cartridges are available from: U.S. Department of Agriculture, Idaho Supply Depot, Pocatello, Idaho. See Swihart and Conover (1991) for information on the effectiveness of various chemical repellents on garden plants.

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.

Negative Impacts: crop pest

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.

Positive Impacts: research and education

Comments: Sometimes regarded as a pest when causing damage to crops, gardens, landscaping, or structures.