Groundhog’s Real Day

A groundhog pokes its head out of a hole along the Three Rivers Heritage Trail on the South Side in August 2020. (Post-Gazette)

Punxy has Phil, but meet the real deal in Pennsylvania fields and backyards

Who does Bill Murray think he is? His 1993 rom-com radically changed popular understanding of southwestern Pennsylvania’s best-known mythological tale.

Before the movie “Groundhog Day” became a box office hit, Feb. 2 had nothing to do with a time loop that imprisons its temporal captives until they do what eternity intends. Since 1887, that day had been all about predicting the first day of spring.

But even Punxsutawney Phil is just a meteorologically inclined caricature misrepresenting the unseen world of a biological marvel: the whistle pig.

Also known for that tongue twister about tossing wood, French Canadians refer to Marmota monax as “siffleux” (whistle), the sound it makes when sensing danger.

A groundhog gives a whistling cry. (YouTube)

The groundhog is one of nature’s habitat engineers — an adaptive rodent that influences land-based ecosystems throughout eastern United States, Canada and Alaska. Before European colonists cut trees to clear farmland, groundhogs were creatures of woodland edges where they could rapidly climb trees to escape predators. They can still climb, but are more often seen alone in low-cut fields casually munching ground-level foliage.

“They have a thumb-like appendage that helps them to climb,” said Henry Kacprzyk, a biologist at the Pittsburgh Zoo and Aquarium in Highland Park. “But they really have no way of foretelling the end of winter.”

Punxsutawney Phil shows his paws on Groundhog Day 2011. A bit of the thumb-like appendage can be seen on the paw to the right. (John Heller/Post-Gazette)

With the exception of “that one they grab and pull up from its den in February,” he said, groundhogs are true hibernators. They would rather sleep through winter than prognosticate.

“Down in their burrows, their body temperature drops to 40-45 degrees and they survive on the fat their body stores,” he said. “When the ground around them warms during the longer days of spring, the first thing they do, even before eating, is come out and look for a mate.”

Family Dynamics

A litter of groundhogs emerges from the underside of a propane tank on a farm in Mason County, Ky., in May 2005. (AP Photo/The Ledger Independent, Terry Prather)

Unlike prairie dogs and other members of the marmot family that gather in close-knit socially complicated colonies, groundhogs live most of their lives alone.

She-chucks mate in their second year. They are not monogamous. Couples shack up in the female’s den throughout the 31- to 32-day gestation. She kicks him out shortly before dropping her litter in April or May.

Litters average three to five pups, but can include up to nine siblings — all born blind, hairless and weighing about 1.5 ounces. In August, fully furred and able to see, they follow mom out into the great big world for the first time.

By September, she recognizes an annoying subterranean failure to launch and chases her young from the burrow. They start their own lives, scraping out dens rarely closer than about 20 yards — often farther — from mom’s hole. As adolescents and adults, groundhogs seldom if ever interact with their parents.

Hiding at home


Groundhog burrows can be elaborate and long with emergency exits and separate chambers. (Carnegie Museum of Natural History)

The familiar mound of dirt at the burrow entrance is only the front door. Tunnels can be expansive — up to 45 feet in length and as deep as 5 feet. The hallways are forked with passages leading to several hidden escape exits and rooms custom designed for sleeping, hibernation nesting, food storage and excrement disposal.

Groundhogs prefer to live in open grasslands and woodland edges where predators can be easily seen from a distance. In Pennsylvania, immature chucks often fall prey to foxes, coyotes and any animal that eats meat including eagles, hawks and other avian predators.

A bald eagle feeds on a groundhog carcass in August 2011. This photo was taken by a motion-sensitive field camera at a Lawrence County camp owned by Dave Dombrosky of Scott.

Adult females average nearly 8 pounds; adult males generally weigh more. That’s a heavy load for most regional predators, which are naturally wary of a grownup groundhog’s defenses. After whistling, groundhogs duck and cover in their dens or fight back savagely with beaver-like incisors. The most consistently successful groundhog predator is the automobile.

Groundhogs can be dangerous in other ways.

Livestock break legs after accidentally stepping into a groundhog hole. Agricultural machinery breaks when hitting unseen mounds and burrow entrances, and all that groundhog digging and scraping breaks down the soil causing erosion of financially valuable fields.

Many farmers are OK with licensed hunters reducing groundhog populations. Liberal regulations provide an open season except for two weeks before Christmas when deer seasons are closed.


A groundhog picnics in Schenley Park in 2014. (John Heller/Post-Gazette)

Want to see one? Go to the Pittsburgh Zoo. But Kacprzyk says they’re not in an exhibit.

“They show up as they do in a lot of places with grassy areas,” he said. “They’re always at Kid’s Kingdom and across the street beside the [Highland Park] reservoir.”

A groundhog looks through a door outside Rivers Casino on the North Shore in 2021. (Post-Gazette)

If Punxutawney Phil’s real-life relatives are eating your vegetable garden, they are relatively easy to catch in a live trap placed about 10 feet from a burrow entrance and baited with a cut turnip, tomatoes or their favorite, apples.

Unlike most wildlife, solitary groundhogs naturally spread out, usually avoiding territoriality, overpopulation and inbreeding. Unless relocation spreads a disease, it’s generally safe to release your unwelcome garden raider in a sparse forest or field.

John Hayes:

Fast facts about groundhogs:

Name: The word “woodchuck” has nothing to do with wood or discarding things. The Algonquin people called them “wuchak.”

Food: Adult groundhogs can consume a pound of vegetation in a day. Mostly vegan, they eat wild grasses and farm crops but will snack on grasshoppers, grubs, snails and even baby birds when they can catch them. Unlike most rodent species, groundhogs don’t drink water, intaking it through the vegetation they eat.

Fight or flight: Groundhogs would rather duck into their burrows than fight. If necessary, they can climb trees and swim to escape attack. When cornered, they aggressively charge, bearing four sharp incisors.

Life span: Groundhogs usually live two to three years in the wild, but have been known to survive for six years.

As prey: As per published works and a statewide study in Pennsylvania, groundhogs are the third most common prey of coyotes.

Human impact: Because of agriculture and improved farming methods, the continental groundhog population is far greater than it was at the start of European colonization. Vehicles pose a threat to them but not so much as to deplete their population.

Danger to humans: Groundhogs don’t usually bite but can be a vector for rabies. A rabid groundhog could attack.

Prognostication skills: Well, they know to duck into the hole when it’s raining.

Culinary rating: Eating only agricultural crops and the best field grasses, groundhog meat is generally lean, tender and moist, similar to rabbit. Farmers and groundhog hunters roast the meat in olive oil with rosemary and garlic; add small chunks to slow-cooked stews; bake it with carrots, mushrooms and celery in meat pies; or braise it in wine and serve over al dente pasta.

Source: Journal of the Pennsylvania Academy of Science, Journal of Wildlife Management,