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Species Profile

Groundhog (Woodchuck)

Marmota monax

Dig deep. Sleep deeper.
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Groundhog (Woodchuck) Distribution

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groundhog coming out of burrow

At a Glance

Wild Species
Also Known As whistle-pig, whistlepig, whistler, land beaver, chuck
Diet Omnivore
Activity Diurnal+
Lifespan 3 years
Weight 6.3 lbs
Status Least Concern
Did You Know?

An adult groundhog is typically 41-68 cm long, with a 9-18 cm tail, and weighs about 2-6.3 kg (seasonal and regional variation).

Scientific Classification

The groundhog (also called the woodchuck) is a large ground-dwelling squirrel (a marmot) known for burrowing, seasonal hibernation, and folklore such as Groundhog Day.

Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Rodentia
Family
Sciuridae
Genus
Marmota
Species
monax

Distinguishing Features

  • Stout-bodied marmot with short ears and a bushy, flattened tail
  • Strong digging claws; lives in complex burrow systems
  • Coarse brown to grizzled fur; adults typically much larger than most squirrels
  • True hibernator with marked seasonal fattening and long winter torpor

Physical Measurements

Males and females differ in size

Length
1 ft 10 in (1 ft 4 in – 2 ft 3 in)
1 ft 9 in (1 ft 4 in – 2 ft)
Weight
9 lbs (4 lbs – 20 lbs)
7 lbs (4 lbs – 11 lbs)
Tail Length
6 in (4 in – 7 in)
5 in (4 in – 7 in)
Top Speed
10 mph
About 16 km/h

Appearance

Primary Colors
Secondary Colors
Skin Type Dense mammalian fur (coarse guard hairs over a thick underfur); seasonally molted with a heavier late-summer/fall coat supporting prolonged hibernation.
Distinctive Features
  • Large, robust ground-dwelling sciurid (marmot) with short legs, heavy body, and a short, bushy tail; adapted for digging with strong forelimbs and long, curved claws.
  • Adult size (typical ranges reported): head-body length 41-67 cm; tail length 9-15 cm (Animal Diversity Web: Marmota monax).
  • Body mass commonly ~2-6.3 kg, with individuals in late summer/fall reaching substantially higher pre-hibernation masses (values up to ~9 kg are reported in field references; ADW notes strong seasonal mass gain).
  • Small, rounded ears that do not project far beyond the fur; eyes laterally placed; muzzle blunt.
  • Incisors large and chisel-like (rodent dentition) used for cutting vegetation and for gnawing; cheek pouches are absent (distinguishing from some other rodent groups).
  • Burrow specialization: typically constructs multi-entrance burrow systems with a nest chamber and dedicated latrine areas; entrances often have a soil mound from excavation.
  • True hibernator: Marmota monax can drop body temperature to about 2–5 °C and slow heart rate to single digits (around 4–10 beats per minute). Used as a hibernation study model.
  • Range context (appearance-relevant): widespread across eastern and central North America; pelage tone can vary regionally (more rufous vs. more gray-grizzled) while maintaining the same grizzled/agouti pattern.

Sexual Dimorphism

Sexual dimorphism is modest. Males average slightly larger/heavier than females in many populations, but there is extensive overlap; both sexes share the same overall grizzled/agouti coloration and general morphology (field accounts summarized in species references such as ADW).

  • Slightly greater average body mass and linear dimensions in many populations; adult males often appear more thick-necked/large-headed, especially pre-breeding.
  • Males commonly show earlier seasonal emergence and wider ranging during the brief breeding period (behavioral dimorphism rather than coloration).
  • Slightly smaller average body size; mammary development becomes evident during lactation (seasonal, not a permanent external trait).
  • Pelage coloration/pattern generally indistinguishable from males outside reproductive condition.

Did You Know?

An adult groundhog is typically 41-68 cm long, with a 9-18 cm tail, and weighs about 2-6.3 kg (seasonal and regional variation).

It is a "true hibernator": body temperature can drop from ~37°C to ~5°C during hibernation, with heart rate falling from ~80 bpm to ~4-10 bpm in deep torpor.

Burrow systems commonly have 2-5 entrances and can include ~6-20 m of tunnels with separate nesting and "toilet" chambers.

Breeding usually occurs soon after spring emergence; gestation is about 31-32 days and litters are commonly 2-6 pups (often 3-5).

Wild lifespan is often only 2-3 years (predation, vehicles, hunting), but individuals can reach ~6 years in the wild and up to ~14 years in captivity.

Despite the name, "woodchuck" doesn't refer to chucking wood; it comes from an Algonquian term (often glossed as meaning "fisher") that European settlers adapted into the modern English name.

Groundhogs are in the squirrel family (Sciuridae): they're marmots (genus *Marmota*), close relatives of western North American marmots and Eurasian marmots.

Unique Adaptations

  • Extreme hibernation physiology (major reductions in body temperature, heart rate, and metabolism) enabling survival through prolonged winter food scarcity.
  • Robust digging toolkit: strong forelimbs, curved claws, and a low, muscular build adapted for moving large volumes of soil.
  • Continuously growing incisors (rodent trait) suited for cutting tough vegetation and occasionally gnawing woody stems and roots.
  • Dense fur and substantial subcutaneous fat that provide insulation and energy reserves for long torpor bouts.
  • Wide-set eyes and upright "lookout" posture that improve predator detection in open edges, fields, and suburban habitats.

Interesting Behaviors

  • Intensive burrow engineering: excavates soil with powerful foreclaws and teeth, creating multi-chamber burrows for nesting, refuge, and latrines.
  • Seasonal rhythm: hyperphagia in late summer/fall to build fat reserves, followed by months-long hibernation underground.
  • Vigilance and alarm calling: often stands upright ("periscoping") to scan; gives a sharp whistle when threatened.
  • Burrow "management": uses different entrances for escape routes and may plug openings with soil during winter to stabilize the hibernaculum.
  • Thermoregulatory basking: spends time sunning near burrow mouths to warm up after cold nights or after spring emergence.
  • Mostly solitary living: adults typically maintain separate burrows and tolerate others mainly during the breeding season and when females rear young.

Cultural Significance

Groundhog (woodchuck) (Marmota monax) is common in eastern and central North America, living at forest edges, farms, and suburbs. Its burrows shape soil and shelter other animals. People know it for Groundhog Day (Feb 2) and a famous tongue-twister.

Myths & Legends

Groundhog Day comes from a Pennsylvania Dutch tradition on February 2 (Candlemas): if a groundhog (woodchuck, Marmota monax) sees its shadow, six more weeks of winter follow; if not, spring comes early.

European Candlemas weather-forecasting used other animals (notably the hedgehog and badger in German areas). German-speaking settlers in Pennsylvania switched the custom to the local groundhog (woodchuck, Marmota monax).

In Punxsutawney, Pennsylvania, the Phil legend says the same weather-telling groundhog lives across generations. Festival folklore claims a special 'Groundhog Punch' drink given each year keeps him alive.

Name and language folklore: 'woodchuck' is often said to come from an Algonquian word (often said to mean 'fisher'), a tale told in local histories about Native and colonial words mixing into English.

Tongue-twister tradition: the popular rhyme "How much wood would a woodchuck chuck..." functions as a piece of modern folk culture, turning the animal into a playful figure associated with impossible feats of work and chewing.

Conservation Status

LC Least Concern

Widespread and abundant in the wild.

Population Stable

Life Cycle

Birth 4 kits
Lifespan 3 years

Lifespan

In the Wild
1–6 years
In Captivity
1–14 years

Reproduction

Mating System Polygyny
Social Structure Solitary
Breeding Pattern Seasonal
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Groundhog (woodchuck; Marmota monax) breed once a year after hibernation. They are mostly solitary and usually polygynous: males visit several females, no lasting pair bond or father care. Gestation ~31–32 days; litter 2–6; young leave burrow ~5–6 weeks.

Behavior & Ecology

Social None (typically solitary; temporary family units at burrows) Group: 1
Activity Diurnal, Crepuscular
Diet Omnivore Legumes-especially clover and alfalfa-are widely reported as preferred forage items for the groundhog (woodchuck) in field accounts (e.g., Animal Diversity Web species account).
Seasonal Hibernates

Temperament

Generally asocial outside the breeding season
Territorial around burrow entrances and core feeding areas (chasing, lunging, and threat postures in close encounters)
High vigilance; frequent upright 'periscope' scanning near burrow
Risk-averse with rapid retreat to burrows; can become aggressive if cornered
Strong site fidelity to established burrow systems (multi-entrance burrows used for refuge, nesting, and hibernation)

Communication

sharp whistle/alarm call Anti-predator warning; source of the name "whistle-pig" in some regions
short barks/chucks during agitation or close encounters
high-pitched squeals during fighting or handling
tooth chattering in threat contexts
scent marking and individual odor cues Notably via anal glands; also urine/feces at latrine sites near burrow areas
visual signals: upright posture (vigilance display), tail flicking, and rapid retreat to burrow as an alarm cue to nearby conspecifics
tactile contact (nose-to-nose investigation) primarily during mating or mother-young interactions

Habitat

Biomes:
Temperate Forest Temperate Grassland
Terrain:
Plains Hilly Valley Riverine Coastal
Elevation: Up to 6561 ft 8 in

Ecological Role

Burrowing, primarily herbivorous consumer that can function as a local agricultural/garden herbivore and occasional opportunistic predator of small animal matter; also an ecosystem engineer through extensive burrow construction.

vegetation herbivory influencing plant community composition in fields/edges soil turnover, aeration, and mixing via burrowing (ecosystem engineering) creation of burrow refugia used secondarily by other wildlife (e.g., small mammals, reptiles, amphibians) nutrient cycling through concentration of plant material and waste near burrow systems prey base support for predators (e.g., coyotes, foxes, raptors) through biomass production

Diet Details

Main Prey:
Insects Other invertebrates Bird eggs and nestlings
Other Foods:
Grasses Legumes Forbs Leaves and stems of wild plants Vegetables Fruits and berries

Human Interaction

Domestication Status

Wild

Marmota monax, the groundhog or woodchuck, is a wild burrowing mammal and is not domesticated. People have hunted it for meat and sometimes fur, treated it as a farm and garden pest for digging and plant-eating, and used it in research on hibernation and disease. Some get used to people or are kept with permits.

Danger Level

Moderate
  • Bites and scratches when cornered/handled; large incisors can cause lacerations
  • Zoonotic disease risk consistent with wild mammals (rabies exposure risk is the primary public-health concern; also ectoparasites such as ticks/fleas)
  • Burrow-related hazards: structural undermining of sheds/porches/retaining walls; damage to farm equipment/irrigation; trip hazards for humans and livestock
  • Road hazard from animals crossing or burrow placement near roads/embankments

As a Pet

Not Suitable as Pet

Legality: Groundhogs (Marmota monax) are North American wild animals and are usually illegal to keep as pets without a wildlife rehab license or a state permit; allowed cases need proof it was gotten legally and follow cage and inspection rules.

Care Level: Expert Only

Purchase Cost: Up to $500
Lifetime Cost: $3,000 - $15,000

Economic Value

Uses:
Agriculture/Property impact (damage and control costs) Game species (regulated hunting in some areas) Biomedical research model (hepatitis B / liver cancer; hibernation physiology) Education/folklore tourism (e.g., Groundhog Day events)
Products:
  • Meat (local/seasonal use where hunted legally)
  • Fur/pelts (limited/local use)
  • Research animals/data (woodchuck hepatitis virus model; hibernation studies)
  • Wildlife-viewing and event revenue tied to Groundhog Day folklore

Relationships

Related Species 8

Yellow-bellied marmot Marmota flaviventris Shared Genus
Hoary marmot Marmota caligata Shared Genus
Alpine marmot Marmota marmota Shared Genus
Olympic marmot
Olympic marmot Marmota olympus Shared Genus
Vancouver Island marmot Marmota vancouverensis Shared Genus
Black-tailed prairie dog Cynomys ludovicianus Shared Family
Thirteen-lined ground squirrel Ictidomys tridecemlineatus Shared Family
Eastern gray squirrel
Eastern gray squirrel Sciurus carolinensis Shared Family

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Black-tailed prairie dog Cynomys ludovicianus Fills a similar niche as a burrowing, largely herbivorous ground-dwelling sciurid that alters habitat with extensive burrow systems. Prairie dogs are more colonial, but both act as ecosystem engineers and are prey for similar mid-sized and large predators.
American badger Taxidea taxus Occupies a similar burrow-associated terrestrial niche in open habitats and overlaps strongly in predator-prey dynamics with groundhogs. Badgers also excavate and use dens extensively, and both influence soil structure and vegetation through digging.
Eastern cottontail
Eastern cottontail Sylvilagus floridanus Comparable role as a common edge-habitat herbivore in eastern North America; both are important prey for canids, felids, and raptors, and both often forage on grasses, forbs, and crops near cover. Eastern cottontails use forms and brush rather than deep burrows.
Raccoon
Raccoon Procyon lotor Frequently uses groundhog burrows for denning and winter shelter in some regions. Ecological linkage is through shared use of burrow structures (commensal use of refuges) and overlapping use of edge habitats.

“Unlike other marmots, they prefer low-lying areas.”

The groundhog is a large lowland rodent found throughout most of the United States. and Canada. Like all rodents, they are curious, intelligent animals who can survive in various environments. They belong to a group of ground squirrels known as marmots. Other names for this animal include woodchuck, thick wood badger, moonack, land beaver, and whistle pig.

4 Incredible Facts About Groundhogs!

animals unique to North America: groundhog

Woodchucks are master burrowers with strong paws and claws made for digging.

  • They can climb trees.
  • They build large, extensive underground burrows.
  • They whistle to each other as warnings.
  • They are excellent swimmers.

You can check out more incredible facts about groundhogs.

Scientific Name

Its scientific name is Marmota monax but it is also known as a woodchuck. The name, woodchuck has nothing to do with wood or chucking but stems from the Algonquian word for the animal, wuchak.

Evolution

Vintana sertichi

Vintana sertichi is an ancient ancestor of the groundhog that lived 66 – 70 million years ago.

Not much is known about the earliest relatives of the groundhog, but a fossil discovered in 2014 has solved a piece of the puzzle. Scientists reconstructed fossil fragments found in Madagascar to reveal a five-inch-long skull of an ancient groundhog that lived between 66 and 70 million years ago.

Vintana sertichi was a large rodent-like creature weighing an estimated 20 pounds. This little mammal was small among its giant dinosaur neighbors – but it possessed a powerful bite. The animal had big eyes, good hearing, and a keen sense of smell. Like modern groundhogs, Vintana ate roots, seeds, and nutty fruits. Like modern rodents, the creature had massive chewing muscles that moved its jaw upwards and backward.

Vitana belonged to a group of early mammals called Gondwanatherians that was previously known only from their teeth. They lived in the ancient southern supercontinent of Gondwana, among the dinosaurs. The Vitana fossil is only the third mammalian skull from the Cretaceous era to be found in the southern hemisphere.

Appearance

isolated groundhog

Groundhogs are large rodents with thick fur and chubby bodies.

A groundhog is a large, stocky rodent covered in long, thick fur. It has a squirrel-like face with large black eyes and an inquisitive expression. Groundhogs are easily recognizable for their chubby bodies, broad, bushy tails, and large claws.

This rodent typically stands about two feet tall. Its tail can reach 10 inches in length. Most groundhogs weigh 13 to 17 pounds, about the weight of a large domestic cat or a small dog.

Groundhogs’ most distinctive features are their four long, sharp incisors. They have two on top of their mouth and two on the bottom. While many marmots have yellow teeth, the incisors of groundhogs are usually white.

Behavior

groundhog coming out of burrow in the snow

Groundhogs dig elaborate burrows where they live year-round and hibernate during winter.

Groundhogs are intelligent animals with complex social interactions. They form close bonds with their young and whistle to communicate information about threats to each other.

Despite their bulky size, they are fast runners, good climbers, and excellent swimmers. It’s estimated they can reach a top speed of almost 10 mph.

These skills give them advantages against their predators. Groundhogs are constantly alert for threats, and it’s common to see them standing on their hind legs to survey their territory. They will whistle at each other when they sense threats, which has led to one of their common names, “whistle pig.”

Groundhogs hibernate every winter. During hibernation, their bodies slow down considerably – their breath slows from 80 beats a minute to five beats a minute. Their respiration drops from 16 breaths per minute to two per minute. Their body temperature drops from 99 degrees Fahrenheit to as low as 37 degrees.

They emerge from their burrows in early February. If an emerging woodchuck senses that winter is truly over, it will walk out of its burrow. If it judges that the weather is still too cold for foraging, it will return to its burrow.

This annual behavior has led to many myths about groundhogs and their ability to predict the weather. In the United States, groundhog predictions have led to the establishment of Groundhog Day. Held on February 2 every year, the highlight is watching a chosen rodent emerge from its burrow and decide whether to come out or return inside. While people think this depends on whether the groundhog sees its shadow, that myth isn’t true. The groundhog uses other senses to determine if winter is over.

According to tradition, if the animal doesn’t see its shadow, spring is around the corner. However, if he sees his shadow, he will return to his burrow, and we can expect another six weeks of winter. Many cities and states have their favorite prognosticators, but Punxsutawney Phil is undoubtedly the most famous.

Punxsutawney Phil: The Most Famous Groundhog That Ever Lived

Punxsutawney Phil on Groundhog Day

Punxsutawney Phil is famous all over the world for predicting the arrival of spring on Groundhog Day.

A resident of Punxsutawney, Pennsylvania, Phil has been “prognosticating” the weather since 1886. There have been many “Phils” since then, but Punxsutawney maintains a legend that Phil took an “elixir of life” that gave him eternal life.

The town established the tradition of visiting Gobblers Knob, the site of Phil’s burrow, in 1887. Today, visits to Gobbler’s Knob are a major source of income for the town. Thousands of tourists come to see Phil deliver his yearly weather prediction.

The story was immortalized in the 1993 movie Groundhog Day, in which Bill Murray was condemned to repeat Groundhog Day over and over until he learned to become a more caring person. The movie cemented Phil’s popularity and turned the town into even more of a tourist attraction.

The current Punxsutawney Phil lives in a climate-controlled, manmade burrow. You can visit him any time of year in Punxsutawney.

Punxsutawney Phil Statue in Punxsutawney, Pennsylvania

Punxsutawney Phil is on public display in a man-made burrow in Pennsylvania.

Phil’s activities have not been without controversy. The animal welfare group People for the Ethical Treatment of Animals (PETA) has repeatedly asked the town of Punxsutawney to replace Phil with a robot. They say forcing Phil to live in captivity, travel to shows, and appear in front of crowds constitutes cruelty to animals.

According to the Introverted Activist blog, “Groundhogs are wild, prey animals, making them naturally fearful of situations like, say, being on constant public display…being handled by various humans in any capacity; being hoisted into the air before a huge crowd of people while being bombarded with loud sounds, bright lights, and other disturbing sensations, especially when they’d rather be hibernating.”

Despite these criticisms, there seems to be no move to replace Phil with a robot or an animal more used to being around humans.

Habitat

groundhog standing on top of burrow

Groundhogs help maintain healthy soil conditions in woodland habitats by burrowing.

While most marmots live in rocky, mountainous areas, woodchucks prefer to live in regions of woodland and lowland plains. They live in fields, pastures, farmed areas, gardens, and hedgerows. In these habitats, they are considered vital habitat engineers, similar to the way beavers are critical habitat engineers in ponds. Woodchucks help maintain healthy soil conditions in woodland soils because of their constant burrowing activity.

They are burrowing rodents. They build extensive underground homes known as burrows, where they stash food, hide from predators, and raise their young. These complex settlements can grow quite large. Some burrows have been measured at 66 feet long.

Diet

What Do Groundhogs Eat
Groundhogs eat bark, vegetation, insects, and fruit.

Groundhogs are omnivores, but their diet is mostly vegetarian. They primarily eat grasses, plants, flowers, fruits, tree bark, and vegetables. Some favorite groundhog foods include dandelions, sheep sorrel, buttercups, raspberries, clover, and alfalfa. On occasion, they may eat grubs, grasshoppers, and snails.

They are hearty eaters. They eat heavily during the spring, summer, and fall. They do this to build up fat reserves that will get them through three months of hibernation. In winter, they go into their burrows and hibernate.

Predators and Threats

fox scream at night - red fox in field

Foxes, coyotes, and bobcats are among the predators of groundhogs.

The groundhog is prey food for large carnivores, including coyotes, badgers, bobcats, and foxes. Raptors and small animals may sometimes eat their pups.

They have ways to protect themselves. Their teeth and claws are sharp, and they won’t hesitate to fight when threatened. Retreating into their burrows is also an excellent protective strategy because most animals won’t follow them underground.

Humans are another threat. These voracious eaters can eat their way through a backyard garden or a small farm in short order. Gardeners and farmers regularly attempt to keep them from devouring their crops. They are also a major target of legal hunting for their fur and meat.

Many people consider them pests, but one man decided to stop fighting nature and respond in an entirely different way. In a video that went viral on social media, he documented how he built an entire vegetable garden just for the local family of groundhogs.

Reproduction and Life Cycle

Groundhog

Female groundhogs give birth to two to six pups and cares for them for around three months.

In February, a male emerges from hibernation and goes looking for a female. He enters the female’s burrow and mates with her. After a gestation period of about 32 days, the female gives birth to two to six babies, which are known as pups.

The pups are born blind and hairless, and the mother feeds them for the first six weeks. At three months of age, they can forage and eat on their own. After about a year, most pups leave to build their burrows.

Groundhogs are not monogamous, but they may spend time together as family groups when they forage for food.

Most live about six years in the wild. In captivity, they can live up to 14 years.

Population

Groundhogs are native to the United States and Canada. Their estimated population is over 200 million.

groundhog

Groundhogs are quite vocal with calls that sound like whistling.

Enjoy Groundhogs Every Day

You don’t need to wait until Groundhog Day to enjoy these intelligent, amusing animals. You can see them in most wooded and forested areas in the United States and Canada. You may even have a family of them living in your backyard.

groundhog coming out of burrow

If your home is in the country or suburbia, chances are that a groundhog lives near you.

View all 261 animals that start with G

Sources

  1. National Geographic / Accessed October 21, 2021
  2. LiveScience / Accessed October 21, 2021
  3. The Punxsutawney Groundhog Club / Accessed October 21, 2021
  4. PETA / Accessed October 21, 2021
  5. Introverted Activists / Accessed October 21, 2021
  6. ThoughtCo. / Accessed October 21, 2021
Lisha Pace

About the Author

Lisha Pace

After a career of working to provide opportunities for local communities to experience and create art, I am enjoying having time to write about two of my favorite things - nature and animals. Half of my life is spent outdoors, usually with my husband and sweet little fourteen year old dog. We love to take walks by the lake and take photos of the animals we meet including: otters, ospreys, Canadian geese, ducks and nesting bald eagles. I also enjoy reading, discovering books to add to my library, collecting and playing vinyl, and listening to my son's music.

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Groundhog (Woodchuck) FAQs (Frequently Asked Questions)

Groundhogs are a species of marmot. In total, there are 15 different marmot species.