Hobbies And Interests
Hibernation
Winter does drastically affect groundhog behavior. Groundhogs -- a member of the squirrel family -- retreat to their dens in the winter. The dens, which as the "groundhog" name might suggest, are located within the ground. Much like bears, groundhogs hibernate within the dens, usually after the first cold frost in winter. They emerge for mating after hibernation usually around February.
Body Temperature
During hibernation, the groundhog's body changes drastically, often dipping to temperatures matching that of the den, which can be as low as 40 degrees. The area of the den where they rest is called the "hibernaculum," which is also the deepest part within the den. The depth allows it to be relatively free of frost, which would otherwise cause the groundhog to use too much metabolic energy to stay warm.
Fat Reserves
During winter, hibernation becomes an extremely useful survival tactic as it allows animals to use as little energy as possible. Without hibernation, these animals might not find adequate food supplies during winter to survive with normal metabolic processes. The key to surviving is storing enough fat on the body prior to winter, which is why groundhogs -- like other hibernators -- attempt to "fatten" up in fall.
Groundhog Day
The claim to fame for groundhogs comes from Groundhog Day, a celebration held in Punxsutawney, Pennsylvania, every year on Feb. 2. The holiday dates back to the latter half of the 19th century, each year featuring a celebrity groundhog named Phil. In 1993, a movie named "Groundhog Day" was made, starring Bill Murray; the following year showed the biggest crowds (around 30,000) ever at Gobbler's Knob, the place where the celebration is performed.