On Monday, thousands of people and the media will gather in Punxsutawney to watch a sluggish groundhog, known as "Punxsutawney Phil," awaken from a deep "sleep" to give his annual prediction about the weather. (Actually, a poorly known rumor is that Phil was born and raised in DuBois; he and his family moved to Punxsutawney when he was four months old.)

Legend has it that winter conditions will last another six weeks if Phil sees his shadow on Groundhog Day, Feb. 2. As people gaze and camera lights focus on Punxsutawney Phil and await his prediction, he seems very uninterested in the annual event and appears to be half "asleep."

In fact, this poor groundhog has just been aroused from a lethargic state of hibernation and, thus, is hardly "anxious" to be bothered by all these curious people who seemingly have nothing better to do but to party and disturb him in the wee hours of the morning!

The groundhog or woodchuck is the largest squirrel in the eastern United States. Groundhogs use underground burrows as home sites rather than tree cavities or nests, as seen in some other types of squirrels.

Groundhogs are stocky, solitary animals that are often seen in fields, on golf courses or along roadsides feeding on plant material throughout spring, summer and fall. They survive the rigors of winter by hibernating and living off stored body fat reserves.

In Pennsylvania, groundhogs hibernate from about early November through early February or March. Once in hibernation, groundhogs may infrequently leave their burrow systems for a short time during winter. When groundhogs eventually emerge from hibernation in late winter or early spring, aboveground activity is initially limited to one hour or less.

Mating behavior (e.g., chases aboveground) occurs shortly after emergence, making groundhog activity more conspicuous to humans. Thus, the origin of Groundhog Day probably stems from an occasional and often short-term appearance of groundhogs in mid-winter or later in the year followed by breeding.

Hibernation by a groundhog is remarkably efficient, saving a groundhog about seven times as much energy compared to it remaining in an aroused state. A groundhog may gain over 30 to 40 percent of its body weight by intensive feeding in the autumn and then lose this weight through hibernation. In this alternating cycle of weight gain and loss, each period lasts about 6 months.

During hibernation, the heartbeat of groundhogs goes from 100 beats per minute to 15 beats per minute, and body temperatures are reduced from 96 to 47 degrees Fahrenheit.

To make some sense of this amazing strategy, imagine a 150-pound human gaining about 50 to 60 pounds every autumn and losing this same amount of weight by early spring every year. Also, when in this imaginary state of hibernation, the human would drop his or her breathing rate and body temperature to around 10 beats per minute and 48 degrees Fahrenheit, respectively, for at least three to four consecutive months!

As an aside, the closely related eastern chipmunk, which shows up virtually everywhere on campus, does not truly hibernate but undergoes a state of "shallow" hibernation, referred to as torpor. Chipmunks usually spend less than one day at a time in torpor, although bouts of torpor may extend several days, depending on the individual.

In fact, as many as 30 percent of the chipmunks in a population may not even enter torpor. Occasionally, chipmunks may be seen above ground in the late winter, particularly during the first breeding season, in February or March.

Chipmunks that enter torpor have lowered body temperatures, heart rates and breathing rates. When in torpor, chipmunks also rely on small amounts of body fat accumulated during the previous autumn; but when awake in the burrow system, they feed on stored food items, like acorns.

Moreover, those individuals exhibiting torpor store less food than those that do not.

Torpor may be used by chipmunks to conserve stored food, especially when food is limited or lacking toward the end of winter.

Other squirrels found in Pennsylvania, including gray, red, fox, northern flying and southern flying squirrels do not hibernate or enter torpor. Under harsh winter conditions, however, these squirrels may avoid lower temperatures by becoming less active and spending more time resting in tree cavities or tree nests.

Oh, by the way, ever wonder what animal is smarter than a weather-forecasting groundhog? -- a spelling bee.