The groundhog (Marmota monax), also known as a
woodchuck, is a rodent of the family Sciuridae, belonging to the group of large
ground squirrels known as marmots. It was first scientifically described by
Carl Linnaeus in 1758. The groundhog is also referred to as a chuck,
wood-shock, groundpig, whistlepig, whistler, thickwood badger, Canada marmot,
monax, moonack, weenusk, red monk and, among French Canadians in eastern
Canada, siffleux. The name "thickwood badger" was given in the
Northwest to distinguish the animal from the prairie badger. Monax (Móonack) is
an Algonquian name of the woodchuck, which meant "digger" (cf. Lenape
monachgeu). Young groundhogs may be called chucklings. 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 found through much of the eastern
United States across Canada and into Alaska.
Description
The groundhog is the largest sciurid in its
geographical range. Adults are 16 to 20 inches (40–50 cm) long, including a six-inch
(15 cm) tail. A large woodchuck thought to weigh twenty pounds when carried was
exactly half that weight when weighed by scale. Woodchuck weight ranges from
five to twelve pounds. Extremely large individuals may weigh up to 15 pounds.
Seasonal weight changes indicate circannual deposition and use of fat.
Progressive higher weights are attained each year for the first 2–3 years after
which weights plateau. Groundhogs have four incisor teeth which grow 1⁄16″
(1.5 mm) per week. Constant usage wears them down again by about that much each
week. Unlike the incisors of other rodents, the incisors of groundhogs are
white to ivory white. Groundhogs are well adapted for digging, with short,
powerful limbs and curved, thick claws. Unlike other sciurids, the groundhog's
tail is comparably shorter — only about one-fourth of body length.
Hibernation
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. Groundhogs hibernate longer in northern latitudes than southern
latitudes. To survive the winter, they are at their maximum weight shortly
before entering hibernation. When the groundhog enters hibernation, there is a
drop in body temperature to as low as 35 degrees Fahrenheit, heart rate falls
to 4–10 beats per minute and breathing rate falls to one breath every six
minutes. During hibernation, they experience periods of torpor and arousal.
Hibernating woodchucks lose as much as half their body weight by February. They
emerge from hibernation with some remaining body fat to live on until the
warmer spring weather produces abundant plant materials for food. Males emerge
from hibernation before females. Groundhogs are mostly diurnal, and are often
active early in the morning or late afternoon.
