Photo by: Lesley Mattuchio, www.treknature.com
The woodchuck (Marmota monax), a member of the
squirrel family, is common throughout Indiana. It can be
found in open pastures, woodlots, cultivated and fallow
fields, and along railroad embankments, ditch banks,
roadsides, fence rows, and levees. In cropping areas,
woodchucks consume soybeans, corn and alfalfa. The
extensive burrowing activities of woodchucks in fields
can interfere with farm operations, cause damage to
equipment, injury to livestock, and create significant
erosion problems in levees, pond dams and railroad
embankments. Around private homes, one or two woodchucks are capable of ruining a small garden almost
Woodchucks should not be viewed as pests only,
however; their burrows often provide refuge for other
wildlife such as rabbits, opossums, raccoons, skunks,
foxes, and even some game birds. They also contribute
to the aeration and mixing of the soil through their
burrowing activities. Moreover, many people derive
enjoyment from watching these rodents since they are
one of the few large wild mammals commonly seen
during the day. Thus, woodchucks are an interesting part
of our wildlife and should be controlled only when they
But chipmunks can also be serious destructive
pests when they become numerous around homes and
gardens. The burrowing activity of chipmunks can
cause significant structural damage by undermining
foundations, concrete patios and steps, retaining walls
and sidewalks. They may also be destructive to
gardens when they dig up and eat bulbs and seeds or
attack garden fruits.
The woodchuck is a stocky animal weighing between 4 and 14 pounds and having short, powerful legs,
small ears and a short, bushy tail. The body fur is long,
coarse, and grizzled grayish-brown in color. There are
four-clawed toes on each front foot and five toes on the
hind feet. Its short, stocky appearance gives the impression that the woodchuck crouches close to the ground as
it moves about. Thus, the animal is often referred to as a
Biology and Behavior
Grizzled brownish gray.
The woodchuck is a vegetarian. Various grasses,
clover, alfalfa, plantain, and other types of tender green
succulents make up its diet. In crop areas, it is especially
fond of the soybean plant, but it will also feed on young
corn plants and even ears in the milk stage. An adult
woodchuck consumes between 1 and 1-1/2 pounds of
The greater part of a woodchuck's day is spent in the
burrow presumably sleeping. Feeding periods vary according to weather conditions and the season. During the
cool days of early spring, it is most active during the
warmer parts of the morning and afternoon. However,
during the summer, the warmest parts of the day are
spent in the cool burrow and feeding occurs during the very early morning and again at dusk. Woodchucks are least active on cool, rainy days.
Woodchucks enter hibernation beginning mid-October and emerge during February. They mate shortly after emergence, with a single litter of four to six young born a month later (March-April). The young leave the nest in early July to establish their own burrows and territories. Woodchucks live an average of 4-6 years.
Burrow Construction and Woodchuck Movements
An understanding of burrow construction and of the
movement of woodchucks within and around crop fields
is important for effective control programs. Too often,
only temporary control is achieved because the number
of active burrows and/or the number of woodchucks
within a field and its surrounding area is underestimated.
Woodchucks usually construct two types of dens: winter
dens and summer dens. Winter dens are often located
within wooded or brushy areas and serve as hibernation
chambers, although occasionally they are used year
round. These dens have only one opening, with the
hibernation chamber situated below a tree or stump for
protection against intruders. The winter den is abandoned by the woodchucks several weeks after they
emerge from hibernation.
The animals then move into nearby grassy meadows or crop fields and construct their summer dens.
Soybean, clover, alfalfa, and corn fields are particularly
favored for summer den locations. Summer dens contain
between one and five openings, but typically there is one
main entrance and one or more escape or "plunge" holes.
The plunge holes are often well concealed among vegetation and may even be plugged. If a den has been in use
for several years or by several generations of woodchucks, the burrow system may be complex, lengthy and contain several openings.
It should also be noted that adult woodchucks often construct more than one summer burrow system within a field. Thus, there are auxiliary burrows as well as main or "home" burrows. Because the auxiliary burrows are used for refuge to escape danger during the animals' daily foraging activities, there may be constant back and forth movement between dens during the summer.
The average burrow system is located about 2-4 feet
underground and extends horizontally 15-25 feet (or
more) (Figure 1). The main nest chamber is generally
located at the end of the burrow system, but additional
nests may be constructed in any part of the burrow. The
main entrance to the burrow is characterized by a mound
of fresh earth around the opening as well as by numerous
trails leading to the feeding areas and auxiliary burrow
systems. When other animals such as rabbits, skunks,
foxes, or badgers are using woodchuck burrows, the
fresh earth mound is absent at the entrance. Also, various types of animal remains and feces are often found
around the entrances to dens used by skunks, foxes and
Fig. 1. Diagram of a typical woodchuck burrow.
The daily home range of woodchucks varies considerably. In favorable habitats, such as a soybean field,
woodchucks may forage only 20-30 yards from their
home dens. In less favorable habitats, such as woodlots,
road edges, yards, etc., the woodchuck may travel several hundred yards daily to reach feeding areas. Generally, only one or two adult woodchucks will inhabit one
acre, although occasionally there may be more. Woodchucks are territorial and defend their dens against other
woodchucks except during the breeding season when
the adult male and female will occupy the same den.
Control efforts should be carried out during early spring when active burrows are easy to find, the young woodchucks have not yet scattered, and there is less likelihood of harming other wildlife.
Woodchucks are most practically controlled in crop
fields via fumigation of their dens or by shooting. Around
buildings or high fire hazard areas, or where it is desirable to control the woodchucks with a nonlethal approach, live-trapping is the safest and most appropriate
If the woodchuck population is large, it is important
that control programs be systematic and encompass the
affected field and areas surrounding the field (Figure 2).
Particular attention should be given to well drained
protected areas, wooded crop borders and weedy fence
rows. All active burrows should be flagged to aid in
rechecking and retreating later. If the affected area
includes adjoining farms, cooperation should be sought
from the neighboring farmers. Without a thorough program and cooperation among land owners, long-term
control results are likely to be poor because exterminated woodchucks will be replaced by invading individuals from surrounding areas.
Fig. 2. A two acre area of a soybean
field during mid-summer with woodchuck
den locations, movement between dens,
home ranges, and feeding areas noted.
Fumigating woodchuck burrows is accomplished
using gas cartridges. When ignited, these cartridges
release carbon monoxide into the burrow system, killing
the woodchuck. Gas cartridges are available from local
farm supply stores and some county Extension offices.
Gas cartridges should be used as follows:
Caution should be taken to avoid prolonged breathing of gas cartridge smoke. Also, since sparks may be thrown, gas cartridges should not be used near buildings or any combustible materials.
For best results, burrows should be treated on cool,
rainy days or during periods of inactivity on other days.
Because vacant burrows may be reoccupied by individuals from adjoining areas, all fumigated burrows should
be rechecked weekly for one month. Any reoccupied
burrows should be retreated. Fumigation should not be
done after September since most woodchucks will be in
hibernation and the hibernating chamber is often "walled
off," rendering a fumigation treatment ineffective.
It is easy to live-trap woodchucks from around
buildings or directly outside their dens in crop fields
using either the Tomahawk No. 108, 108.5, 608, 608.5,
or the Havahart Nos. 3, 3A or 1079. Set the live trap in
the trail immediately in front of the main burrow entrance
(Figure 3). Logs, twigs, or stones placed on either side
of the path between the burrow opening and the trap will
aid in funneling the animal toward the trap. If a double
door trap model is used, set both doors of the trap open.
Good baits for woodchucks include apple slices, carrots,
sweet corn, and fresh lettuce.
Fig. 3. Wiremesh live trap.
Live traps may be rented from local humane societies
and animal shelters. They can also be purchased from
those companies listed at the end of this publication.
However, such traps are relatively expensive and their
purchase is hard to justify unless woodchucks, and other
similar-sized animals (e.g., raccoons, opossums, rabbits,
squirrels) pose a regular nuisance to the property owner.
Where legal and safe, the quickest and surest method of eliminating woodchucks is to shoot them with a "varmint rifle" (e.g., scope sighted .243 caliber). A patient marksman can significantly reduce a local woodchuck population in a few days. Hunt during periods of greatest activity on fairweather days.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by State or Federal Agencies is implied. This program serves people of all ages regardless of socioeconomic level, race, color, sex, religion, disability, or national origin. The Wildlife Conflicts Information Hotline is a cooperative program of the United States Department of Agriculture - Animal and Plant Health Inspection Service - Wildlife Services, Indiana Department of Natural Resources-Division of Fish & Wildlife, and Purdue Cooperative Extension Service.