The groundhog, also known as a woodchuck, whistle-pig, or land-beaver in some areas,
is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known
as marmots. Other marmots, such as the yellow-bellied and hoary marmots, live in rocky and mountainous
areas, but the groundhog is a lowland creature. It is widely distributed in North America
and common in the northeastern and central United States as well as Canada. Groundhogs
are found as far north as Alaska, with their habitat extending southeast to Georgia.
Description The groundhog is the largest sciurid in its
geographical range, typically measuring 40 to 65 cm long tail) and weighing 2 to 4 kg.
In areas with fewer natural predators and large amounts of alfalfa, groundhogs can grow
to 80 cm and 14 kg. Groundhogs are well adapted for digging, with short but powerful
limbs and curved, thick claws. Unlike other sciurids, the groundhog's spine is curved,
more like that of a mole, and the tail is comparably shorter as well—only about one-fourth
of body length. Suited to their temperate habitat, groundhogs are covered with two coats
of fur: a dense grey undercoat and a longer coat of banded guard hairs that gives the
groundhog its distinctive "frosted" appearance. In the wild, groundhogs can live up to six
years, with two or three being average. In captivity, groundhogs reportedly live from
9–14 years. Common predators for groundhogs include wolves, cougars, coyotes, foxes, bobcats,
bears, eagles, and dogs. Young groundhogs are often at risk for predation by snakes,
which easily enter the burrow.
The etymology of the name woodchuck is unrelated to wood or chucking. It stems from an Algonquian
name for the animal, wuchak. The similarity between the words has led to the popular tongue-twister:
How much wood would a woodchuck chuck if a woodchuck could chuck wood?
A woodchuck would chuck all the wood he could if a woodchuck could chuck wood!
Diet
Mostly herbivorous, groundhogs primarily eat wild grasses and other vegetation, including
berries and agricultural crops, when available. Groundhogs also eat grubs, grasshoppers, insects,
snails and other small animals, but are not as omnivorous as many other Sciuridae. Like
squirrels, they also have been observed sitting up eating nuts such as shagbark hickory, but
unlike squirrels, do not bury them for future use. Groundhogs hydrate through eating leafy
plants rather than drinking from a water source. Burrows
Groundhogs are excellent burrowers, using burrows for sleeping, rearing young, and hibernating.
The average groundhog has been estimated to move approximately 1 m3, or 2,500 kg, of
soil when digging a burrow. Though groundhogs are the most solitary of the marmots, several
individuals may occupy the same burrow. Groundhog burrows usually have two to five entrances,
providing groundhogs their primary means of escape from predators. Burrows are particularly
large, with up to 14 metres of tunnels buried up to 1.5 metres underground, and can pose
a serious threat to agricultural and residential development by damaging farm machinery and
even undermining building foundations. Behavior
Groundhogs are one of the few species that enter into true hibernation, and often build
a separate "winter burrow" for this purpose. This burrow is usually in a wooded or brushy
area and is dug below the frost line and remains at a stable temperature well above freezing
during the winter months. In most areas, groundhogs hibernate from October to March or April,
but in more temperate areas, they may hibernate as little as three months. To survive the
winter, they are at their maximum weight shortly before entering hibernation. They emerge from
hibernation with some remaining body fat to live on until the warmer spring weather produces
abundant plant materials for food. Groundhogs are mostly diurnal, and are often active early
in the morning or late afternoon. Despite their heavy-bodied appearance, groundhogs
are accomplished swimmers and excellent tree climbers when escaping predators or when they
want to survey their surroundings. They prefer to retreat to their burrows when threatened;
if the burrow is invaded, the groundhog tenaciously defends itself with its two large incisors
and front claws. Groundhogs are generally agonistic and territorial among their own
species, and may skirmish to establish dominance. Outside their burrow, individuals are alert
when not actively feeding. It is common to see one or more nearly-motionless individuals
standing erect on their hind feet watching for danger. When alarmed, they use a high-pitched
whistle to warn the rest of the colony, hence the name "whistle-pig". Groundhogs may squeal
when fighting, seriously injured, or caught by a predator. Other sounds groundhogs may
make are low barks and a sound produced by grinding their teeth. When groundhogs are
frightened, the hairs of the tail stand straight up, giving the tail the appearance of a hair
brush. Reproduction
Usually groundhogs breed in their second year, but a small proportion may breed in their
first. The breeding season extends from early March to mid- or late April, after hibernation.
A mated pair remains in the same den throughout the 31–32 day gestation period. As birth
of the young approaches in April or May, the male leaves the den. One litter is produced
annually, usually containing two to six blind, hairless and helpless young. Young groundhogs
are weaned and ready to seek their own dens at five to six weeks of age. Groundhog mothers
introduce their young to the wild once their fur is grown in and they can see. They encourage
their young to copy their behaviors and during this time may differ from usual routines.
Range The groundhog prefers open country and the
edges of woodland, and is rarely far from a burrow entrance. Since the clearing of forests
provided it with much more suitable habitat, the groundhog population is probably higher
now than it was before the arrival of European settlers in North America. Groundhogs are
often hunted for sport, which tends to control their numbers. However, their ability to reproduce
quickly has tended to mitigate the depopulating effects of sport hunting. As a consequence,
the groundhog is a familiar animal to many people in the United States and Canada.
Relationship with humans Groundhogs may be raised in captivity, but
their aggressive nature can pose problems. Doug Schwartz, a zookeeper and groundhog trainer
at the Staten Island Zoo, has been quoted as saying "They’re known for their aggression,
so you’re starting from a hard place. Their natural impulse is to kill ’em all and let
God sort ’em out. You have to work to produce the sweet and cuddly."
In the United States and Canada, the yearly February 2nd Groundhog Day celebration has
given the groundhog recognition and popularity, as has the movie of the same name. The most
popularly known of these groundhogs are Wiarton Willie, Punxsutawney Phil and Jimmy the Groundhog
well kept as part of Groundhog Day festivities in Wiarton, Ontario; Punxsutawney, Pennsylvania;
and Sun Prairie, Wisconsin, respectively. Famous southern groundhogs include, Smith
Lake Jake from Graysville, Alabama and General Beauregard Lee, is based at the Yellow River
Game Ranch outside Atlanta, Georgia. Groundhogs are used in medical research on
hepatitis B-induced liver cancer. When infected with woodchuck hepatitis B virus, they are
at 100% risk for developing liver cancer, making them a good model for testing hepatitis
B and liver cancer therapies. Groundhog burrows have been known to reveal
at least one archaeological site, the Ufferman Site in the U.S. state of Ohio. Although archaeologists
have never excavated the Ufferman Site, numerous artifacts have been found because of the activities
of local groundhogs. They favor the loose soil of the esker upon which the site lies,
and their many diggings for their burrows have brought to the surface significant numbers
of human and animal bones, pottery, and bits of stone.
One of Robert Frost's best known poems is "A Drumlin Woodchuck," in which he uses the
imagery of a woodchuck dug in to a small ridge as a metaphor for his emotional reticence.
A groundhog figures prominently in the movie Groundhog Day.
References
Further reading Bezuidenhout, A. J. and Evans, Howard E..
Anatomy of the woodchuck. Lawrence, KS: American Society of Mammalogists, 2005. ISBN 9781891276439.
Online at doi:10.5962/bhl.title.61270 External links
Woodchuck, Hinterland Who's Who Woodchuck, Missouri Conservation Commission