Groundhog, woodchuck -- what's the difference?

Woodchuck and groundhog are common terms for the same animal, the rodent with the scientific name of Marmota monax. Most closely related to squirrels, woodchucks actually can climb trees and also swim.

What's so special about Feb. 2?

Celestially speaking, Groundhog Day on Feb. 2 is a "cross-quarter" day, about halfway between the winter solstice in December and the vernal equinox in March, and is celebrated in some cultures as the midpoint of winter. It's not far from the time many groundhogs end their hibernation anyway, around the second week of February.

What's going on in that burrow?

In the winter, not much. Groundhogs go into profound hibernation, greatly reducing their metabolic rate, and their body temperature drops to just a few degrees above ambient temperature. Because their hibernaculum, the deepest portion of the burrow where they hibernate, is below frost line, that produces a body temperature as low as 39-40 degrees F.

What's the wake-up call?

The groundhog's internal clock is believed to be affected by annual changes in the amount of daylight. Hormonal responses to cyclic changes in production of melatonin, a sleep-related hormone, are thought by some to be the signal to wake up.

Why did groundhog fur coats go out of fashion?

Groundhog fur never was in vogue, partly because it is not particularly thick and warm, and because the fur's grizzled grey-brown appearance is more appealing to others of their species than to people. Groundhog hairs are used for tying trout flies, such as the 'Chuck Caddis, and early American Indians once used sturdy woodchuck hides for soles of moccasins.

What's for dinner?

Groundhogs in the wild eat succulent green plants, such as dandelion greens, clover, plantain and grasses. They also are tempted by nearby garden vegetables. At Cornell, they dine on Agway Woodchuck Chow, a similar formulation to rabbit feed but in larger-sized pellets. Woodchucks binge and purposefully put on weight in the summer, reaching their maximum mass in late August. They become lethargic and prepare for hibernation in October. By February, hibernating woodchucks have lost as much as half their body weight.

How much wood could a woodchuck chuck if a woodchuck could chuck wood?

About 700 pounds. Compared to beavers, groundhogs/woodchucks are not adept at moving timber, although some will chew wood. (At Cornell, woodchucks that gnaw their wooden nest boxes are given scraps of 2-by-4 lumber.) A wildlife biologist once measured the inside volume of a typical woodchuck burrow and estimated that -- if wood filled the hole instead of dirt -- the industrious animal would have chucked about 700 pounds' worth.

Sources: College of Veterinary Medicine, Cornell University; New York State Department of Environmental Conservation; Mammals of the Eastern United States, Second Edi tion, William J. Hamilton Jr. and John O. Whitaker Jr.