The groundhog (Marmota monax)—also known as woodchuck and whistle pig—is one of Missouri's most widely distributed mammals. The groundhog’s feeding and burrowing habits—such as in hay or crop fields, home gardens, orchards, and nurseries—can result in conflicts with property owners. Burrows and mounds can be hazardous to farm equipment or horses and riders, and burrows can undermine concrete building foundations, porches, and driveways.
The Wildlife Code of Missouri classifies the groundhog as a game mammal that may be taken during the prescribed hunting season (see current regulations for details). Taking groundhogs during the prescribed season can help control their numbers. Cage-type traps are allowed as a hunting method. The Code also specifies that you may shoot or trap damage-causing groundhogs out-of-season without a permit. Refer to 3 CSR 10-4.130 of the Code for details and restrictions.
Fencing can reduce damage, but groundhogs are good climbers and can easily scale wire fences unless precautions are taken. Fences should be at least 3 feet high and made of heavy poultry wire or 2-inch mesh woven wire. Bending the top 15 inches of the wire fence outward at a 45-degree angle will prevent groundhogs from climbing over the fence. To prevent burrowing under the fence, bury the lower edge 10 to 12 inches below ground, or bend the lower edge in an L-shaped angle leading outward and buried 1 to 2 inches below ground. Prevent groundhogs from burrowing under concrete slabs by burying L-shaped wire mesh along the edge.
An electric wire used in conjunction with fencing can enhance effectiveness. Place an electric wire 4 to 5 inches off the ground and the same distance outside the fence. When connected to a UL-approved fence charger, the electric wire will prevent climbing and burrowing. In some instances, an electric wire alone, placed 4 to 5 inches above the ground, can deter groundhogs from entering gardens. Vegetation in the vicinity of any electric fence should be removed regularly to prevent the system from shorting out.
Fumigants & Repellents
Ammonia-soaked rags are effective repellants for groundhogs. If possible, flooding groundhog dens with water is also effective, as they do not like a wet den and will move on.
Gas cartridges, which are available at farm- and garden-supply stores, have proven to be effective. They produce carbon monoxide that accumulates in lethal amounts when confined within the burrow system. Gas cartridges are filled with combustible materials that are ignited by lighting a fuse. They are not bombs and will not explode if properly prepared and used. CAUTION: Avoid prolonged breathing of smoke. Do not use near buildings or combustible materials.
Instructions for using gas cartridges:
- With a spade, cut a clump of sod slightly larger than the opening of the burrow and place it nearby.
- Punch five pencil-size holes in the end-cap of the cartridge. Insert the fuse to half its length into one of the holes. The cartridge is now ready to use and should look like the illustration.
- Kneel at the burrow opening, light the fuse and immediately place the cartridge as far down the hole as you can. Do not throw it.
- Immediately close the burrow opening by placing the sod—grass side down—over the opening to make a tight seal. (Placing sod grass side down prevents smothering the cartridge with loose dirt). Garbage can covers, sand bags, or other suitable closing devices may be used instead of sod.
- Wait for three or four minutes while watching nearby holes for escaping smoke, then plug them. Repeat until all burrows are closed.
Traps are effective. Cage-type traps should be clean and set during daylight hours. Close or disable the trap at night to prevent non-target catches. Place the trap close to, but not blocking, the burrow entrance. Covering or camouflaging the trap is not necessary. Bait with a slice of apple, cantaloupe, or other fruit. Broccoli or cauliflower also work well. Fresh bait works best, so replace daily.
Body-gripping traps are not allowed for dry-land sets in Missouri. Foothold traps are effective but require special skill and experience. Restrictions on use apply, so see current regulations for details. If this type of trap is needed, the local county conservation agent can likely provide the name of a local trapper who can assist you. In some situations, the Department wildlife biologist can provide instruction, equipment, and assistance.
Groundhogs can be shot with conventional firearms, usually a rimfire. Check with local authorities regarding firearms use. Taken during the prescribed season, a young, medium-sized, properly prepared groundhog makes excellent table fare.