Woodchucks are an "edge" species, living in hedgerows or brush clumps along old fields, pastures, or croplands intermixed with small woodlands. Burrows are dug in well-drained soil along woodland edges and brushy hedgerows, often on rather steep slopes. The animal will also burrow under sheds, porches, decks, or walkways. Burrows are a critical feature of their life style, and typically include multiple entrances. The main shaft may be up to 50 feet in length, with many side passages. The 'chuck usually piles up a mound of dirt and rocks at the burrow entrance, but the entry may otherwise be well-concealed.
Woodchucks are typically daytime animals. During most of the year, their activity peaks in mid-morning and again in the late afternoon, but declines at mid-day. Early and late in the season they may be active only in the afternoon. They enter hibernation in late fall and emerge in early spring. The hibernation period is about 4-4½ months in Pennsylvania and 5 months in upper New York.
Their home range is determined by food availability, but is typically between ¾-2¼ acres.
Home ranges of adult males may overlap those of females, but usually not those of other males. Woodchucks disperse from their birtharea when less than 1 year old, females traveling perhaps ¼ mile and males mile.
Woodchucks are quite wary and on the alert around their burrow entrance and while feeding.
Woodchucks are generalist plant feeders, consuming a wide variety of herbaceous (soft or leafy) vegetation. Studies in Maryland identified 34 plants while a study in Pennsylvania found 46 that were eaten by woodchucks. Clover, wild lettuce, grasses, chickweed, and dandelion appeared among the preferred species. The animals also readily eat hay grasses, alfalfa, corn, and a variety of common garden or commercial crops. Woodchucks readily climb trees and may feed on leaves of certain species, such as mulberry. They may also gnaw woody stems or trees, primarily in spring.
Woodchucks mate in March and April shortly after emergence from hibernation. They can first breed as yearlings (i.e., in their second summer), however only 20-40% of female yearlings do breed. The tiny, feeble young are born in the burrows after a gestation period of 30-32 days.
Based on data from studies of captive animals, litter size averages four to five young.
The pups emerge from the den at about 33 days and are weaned at about 42 days.