Woodchucks use burrows for mating, hiding from predators, and hibernation. One branch of the burrow system leads to a nest chamber containing dried grass. This dead-end nest chamber is sealed with soil during the winter and serves as a hibernation chamber. Woodchucks are most active during early morning and late afternoon when they are feeding. They are vegetarians and eat a variety of broadleafed weeds, including dandelions and plantain.
Woodchucks are particularly fond of legumes, including alfalfa and vetch, clover, peas, and beans.
When not actively feeding, woodchucks can be seen basking or dozing on rocks, stone fences, and logs during the warmest part of the day. In late August and September, woodchucks have voracious appetites as they prepare to hibernate. This deep sleep, when body temperatures drop and heart rate slows to four beats a minute, usually begins in October and continues through February. After hibernation, males usually emerge first and may travel some distance in search of a mate. Once a mate has been located, breeding occurs during March.