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Marmota monaxwoodchuck

By Clinton Tobias

Geographic Range

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kays and Wilson, 2002; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

Habitat

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

  • Range elevation
    low elevation (low) m
    (low) ft

Physical Description

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kays and Wilson, 2002; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

  • Sexual Dimorphism
  • male larger
  • Range mass
    2 to 6 kg
    4.41 to 13.22 lb
  • Range length
    415 to 675 mm
    16.34 to 26.57 in
  • Average basal metabolic rate
    3.696 W
    AnAge

Reproduction

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998)

  • Breeding interval
    Woodchucks breed once yearly
  • Breeding season
    Mating occurs between February and May depending on latitude
  • Range number of offspring
    1 to 9
  • Average number of offspring
    4.5
    AnAge
  • Range gestation period
    31 to 32 days
  • 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

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

  • Parental Investment
  • altricial
  • female parental care
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • inherits maternal/paternal territory

Lifespan/Longevity

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, Jr. and Hamilton, Jr., 1998)

  • 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
    AnAge

Behavior

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. ("The Roots of Marmot Sociality", 2001; "Woodchuck", 2007; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998; Yahner, 2001)

  • Range territory size
    2,500 to >10,000 m^2

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, Jr. and Hamilton, Jr., 1998)

Communication and Perception

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, Jr. and Hamilton, Jr., 1998)

Food Habits

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

  • Animal Foods
  • eggs
  • insects
  • mollusks
  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • flowers

Predation

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, Jr. and Hamilton, Jr., 1998)

Ecosystem Roles

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, Jr. and Hamilton, Jr., 1998)

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

Economic Importance for Humans: Positive

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, Jr. and Hamilton, Jr., 1998)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998)

  • Negative Impacts
  • crop pest

Conservation Status

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.

Other Comments

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. ("Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Yahner, 2001; "Woodchuck", 2007; Forsyth, 1985; Grzimek, 2003; Kurta, 1995; Kwiencinski, 1998; Whitaker, Jr. and Hamilton, Jr., 1998; Yahner, 2001)

Contributors

Clinton Tobias (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), University of Michigan-Ann Arbor, John Berini (editor), Animal Diversity Web Staff, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

herbivore

An animal that eats mainly plants or parts of plants.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

induced ovulation

ovulation is stimulated by the act of copulation (does not occur spontaneously)

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

polygynous

having more than one female as a mate at one time

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Andromeda Oxford, Ltd. 2001. The Roots of Marmot Sociality. Pp. 612-613 in D Macdonald, ed. The Encylopedia of Mammals, Vol. 3, 2 Edition. New York, NY: Facts On File, Inc..

Encyclopaedia Britannica, Inc. 2007. Woodchuck. Pp. 741 in The New Encyclopaedia Britannica, Vol. 12, 15 Edition. Chicago, IL: Encyclopaedia Britannica, Inc..

Forsyth, A. 1985. Mammals of the Canadian Wild. Camden East, Ontario: Camden House.

Grzimek, B. 2003. Woodchuck. Pp. 152-153 in M McDade, ed. Grzimek's Animal Life Encyclopedia, Vol. 16/5, 2 Edition. Farmington Hills, MI: Gale Group.

Kays, R., D. Wilson. 2002. The Mammals of North America. Princeton, NJ: Princeton University Press.

Kurta, A. 1995. Mammals of the Great Lakes Region. Ann Arbor, MI: University of Michigan Press.

Kwiencinski, G. 1998. Marmota monax. Mammalian Species, 591: 1-8.

Whitaker, Jr., J., W. Hamilton, Jr.. 1998. Mammals of the Eastern United States. Ithaca, NY: Cornell University Press.

Yahner, R. 2001. Fascinating Mammals: conservation and ecology in the mid-eastern states. Pittsburgh, Pa: University of Pittsburgh Press.

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