Woodchucks--Habits and Control 

Prepared by: Norman L. Gauthier, Cooperative Extension Educator/Entomologist
Reviewed by: UConn Home and Garden Education Center 2005.

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The woodchuck, or groundhog (also known as the whistle pig), is a member of the rodent family. It has a compact, hefty body, short, strong legs with long, curved claws on the forefeet for digging and a short tail. It is heavily furred and dark brown in color, weighs from five to ten pounds and is 16 to 20 inches long. Although they are slow runners, woodchucks are alert and can quickly move into their dens when alarmed.

Life History and Habits
Woodchucks hibernate during the winter, becoming active in late February and March. Mating occurs in March and a single litter of two to four young is produced annually. The young are weaned by late June or early July, and soon thereafter strike out on their own-usually occupying old, abandoned dens. Older chucks dig the numerous new burrows, which appear during the late summer. Woodchucks are active during the daylight hours, and their range is 50 to 100 feet from their dens.

The den and burrows are extensive and may be used for several years. Burrows may be as deep as five feet and up to 60 feet in length. Woodchucks seem to prefer to construct burrows on or near farmland where crops grow. They frequently may be found in woodlands or in abandoned farmlands and occasionally in urban areas where the combination of food and cover provides a satisfactory habitat.

Woodchucks are voracious feeders. In the early morning and evening periods of the summer, woodchucks actively feed on succulent, green vegetation. They are storing body fat in preparation for hibernation during late fall, usually near the end of October or early November.

Woodchucks feed primarily on vegetables, trees, grasses and legumes. Their favorite foods include various beans, cole crops (broccoli, cabbage, cauliflower etc.), carrot tops, clover, squash and peas. Their gnawing and clawing can kill young fruit trees. Gnawing occurs on the main stems of trees and lower branches close to the burrows and is easily distinguished from vole gnawing by the large size of the incisor teeth marks (1/4 to 3/8 inch wide). This is done as a way to control tooth growth. Their burrowing habits produce mounds of earth and burrow holes that present hazards. The burrows have a main entrance and at least one back door. The main entrance to the burrow is a ten to twelve inch in diameter hole with a mound of soil next to it. There may be well-used path visible leading from the burrow.

Damage Control

  1. Wire fencing will help keep woodchucks out of nursery areas and small plantings. Bury the lower edge 10 to 12 inches deep in the soil to prevent burrowing under the fence. Because woodchucks are good climbers, the fence should be three to four feet high the last one foot left loose and bent out.
  2. Live trapping. Live trapping and relocating are legal in the state of Connecticut.
  3. Rifles with telescopic sights have encouraged the shooting of woodchucks. In recent years, there have been no closed season and no limit on the number of woodchucks to be taken by individual hunters. Check Connecticut Department of Environmental Protection for hunting regulations. If safety requirements are satisfied, landowners and their hunting friends can help reduce the number of woodchucks. Even concentrated hunting may not eliminate woodchucks and some of the problems they create. Landowners and hunters should agree on arrangements for hunting. This will aid in reducing woodchucks and their damage, provide recreational hunting and avoid unsafe practices in the field. Use of rifles is restricted in some towns. Check with local authorities before hunting.
  4. Commercial gas cartridges filled with slow-burning chemicals are available at garden and farm supply stores. All entrances must be sealed with soil or piece of turf big enough to tightly cover the holes. Ignited and placed the cartridge as far back into the burrows as you can. Then seal the main entrance. As the cartridges burn, carbon monoxide and sulfur dioxide fill the tunnels and kill the woodchuck. Before using these cartridges, read and follow all instructions and cautions on the label. The best time of day to find the woodchuck in its burrow is mid day when they go in to stay cool.
  5. Poisonous exhaust fumes of an automobile, truck or tractor may be directed into burrows. This is not always economical. In addition, it is often difficult to reach holes on steep hillsides and in hedgerows. Avoid prolonged breathing of fumes. Connect a hose to the exhaust pipe and run it down into the burrow. Seal the burrow around the hose to prevent gas from escaping. Run the motor about five minutes with the choke partially out. Remove the hose and reseal the burrow opening. Treat all burrows.
  6. No poisons or poisonous baits are registered for woodchuck control in Connecticut.

The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.