As is true for Black Bears, if climate conditions are mild and food (such as remnant corn in fields) is available, Woodchucks have been known to remain active year round in parts of their range. However, they typically hibernate during the winter in underground burrows, living off the fat (equaling about a third of their body weight) they accumulate in late summer and fall. In Pennsylvania, where Groundhog Day is first referenced in North America, male Groundhogs, or Woodchucks, emerge from their burrows at the end of January or beginning of February. In northern New England, however, we don’t usually see signs of this largest member of the eastern squirrel family, Sciuridae, until the end of February or beginning of March, when males actively start searching for mates. Currently our Woodchucks are still curled up in a ball hibernating beneath the ground, with their heart rate reduced from 100 beats a minute to 15, and their body temperature down from about 96°F. to 47°F.
It’s possible that this chipmunk is preparing a nesting chamber in her underground burrow, judging from the amount of dirt that is on her. Sometime between February and early April chipmunks mate. Roughly a month later they give birth to 3 to 5 young in a bulky nest of leaves inside a 24” x 15” x 10” chamber. Within a week, hair and stripes will be evident on the young chipmunks. In about a month, they will venture out of the burrow, looking like small adults.
By the end of this month or the beginning of November, most Eastern Chipmunks will have gathered and stored their winter food supply underground in a special chamber which they will visit every two or three weeks throughout the winter, grabbing a bite to eat. Up to half a bushel of nuts and seeds can be stored here, which means many trips from the food source to the larder. In order to minimize the number of trips, chipmunks cram their cheek pouches as full as possible. The contents that researchers have found in one chipmunk’s two pouches include the following (each entry represents the contents of one chipmunk’s pouches): 31 kernels of corn, 13 prune pits, 70 sunflower seeds, 32 beechnuts, 6 acorns.