Groundhogs absolutely chew wood, and they chew it with enthusiasm. As rodents, groundhogs belong to an order of mammals defined by their gnawing teeth, and those teeth never stop growing. Chewing on wood, bark, roots, and other hard materials is how groundhogs keep their incisors at a functional length. The behavior is biological necessity rather than dietary preference, which is why simply removing one wooden target rarely solves a homeowner’s problem.
Why Groundhogs Need to Gnaw
Every rodent on Earth shares the same dental quirk: incisors that grow continuously throughout life. In groundhogs, the upper and lower pairs of incisors are open-rooted, meaning new tooth material pushes forward from the base at a steady rate. If a groundhog stopped gnawing, its incisors would eventually curve, overlap, or grow into the opposing jaw, making it impossible to eat. This is not a hypothetical risk. Captive rodents that lack adequate gnawing material sometimes develop dangerously overgrown teeth that require veterinary trimming.
Wood happens to be an ideal grinding surface. It is hard enough to wear down enamel at a pace that matches regrowth, yet soft enough that a groundhog can bite into it without cracking a tooth. But groundhogs are not picky. They will gnaw on plastic irrigation pipe, rubber hoses, the undersides of wooden decks, siding, fence posts, and even soft metals like aluminum flashing. Anything that provides resistance against those incisors will do.
How Their Teeth Stay Sharp
Gnawing on external objects is only half the maintenance routine. Groundhogs also sharpen their incisors by grinding the lower pair against the upper pair in rapid, repetitive strokes. During this self-sharpening, the inner surface of the lower incisor is dragged across the tip of the upper incisor, creating a beveled wear facet that keeps the cutting edge chisel-sharp. In woodchucks, this sharpening happens at roughly eight cycles per second, making it one of the fastest repetitive jaw movements recorded in mammals.1PubMed Central. Incisal biting in the mountain beaver (Aplodontia rufa) and woodchuck (Marmota monax)
The result is a pair of incisors that function like self-sharpening chisels. The front surface of a groundhog’s incisor is coated in hard, orange-tinted enamel, while the back is softer dentine. Because the softer material wears away faster, each bite renews the angled cutting edge automatically. This is why groundhog teeth can slice through roots, bark, and even thin plywood without dulling.
What Groundhogs Actually Eat
Despite the wood-chewing, groundhogs are herbivores whose diet is overwhelmingly plant-based. In spring and summer, a groundhog’s menu is dominated by grasses, clover, alfalfa, dandelions, and garden vegetables. They are especially fond of leafy greens, beans, peas, and squash. Fruits like apples and berries get eaten when available. By late summer, groundhogs shift toward higher-calorie foods as they fatten up for hibernation, and they may strip bark from trees or eat more seeds and agricultural crops during this phase.
Wood itself has almost no nutritional value for groundhogs. They lack the specialized gut bacteria that termites and certain beetles use to break down cellulose into usable energy. When a groundhog chews a deck post or a garden fence rail, it is maintaining its teeth, not feeding itself. This distinction matters for control strategies: removing a food source like a vegetable garden may reduce the incentive for a groundhog to hang around your yard, but it will not stop the chewing, because the chewing serves a separate purpose.
The Real Damage Problem Is Usually Underground
Chewed wood gets the attention, but burrowing causes far more structural damage. A single groundhog burrow system can extend 40 to 60 feet laterally and five feet deep, with multiple entrance holes. These tunnels undermine foundations, crack driveways, collapse retaining walls, and create ankle-breaking hazards in yards and pastures. When groundhogs burrow beneath sheds, porches, or concrete slabs, the displaced soil leaves voids that cause settling over time.
Groundhog burrows also redirect water flow. Rain drains into burrow openings and follows the tunnel network underground, sometimes pooling against basement walls or eroding soil under walkways. Farmers in the eastern United States and Canada consider groundhog burrows a serious hazard for livestock, because a horse or cow stepping into a burrow entrance can break a leg.
So while finding teeth marks on your deck railing is annoying, it is worth checking whether the same groundhog has been digging beneath the structure. The chewing is cosmetic damage. The burrowing is structural.
How to Stop Groundhogs From Chewing Wood on Your Property
Because gnawing is instinctive, you cannot train a groundhog to stop. You can only make your property less attractive or physically block access. Here are the approaches that actually work, roughly ordered by effectiveness.
- Hardware cloth barriers: Wrapping vulnerable wooden structures in galvanized hardware cloth with a half-inch mesh is the most reliable physical deterrent. Groundhogs can chew through chicken wire, so use 16-gauge or heavier welded wire. Bury the bottom edge at least 12 inches below ground and bend it outward in an L-shape to prevent digging underneath.
- Exclusion fencing: A fence at least three feet tall, made of sturdy welded wire, with another 12 inches buried underground in an outward L, will keep groundhogs out of gardens and away from structures. Adding an outward-angled extension at the top discourages climbing, since groundhogs are surprisingly good climbers.
- Taste and scent repellents: Commercial repellents containing capsaicin (hot pepper extract) or thiram (a bitter-tasting fungicide) can be applied to wood surfaces. These work in the short term but need reapplication after rain. Homemade versions using cayenne pepper mixed with water and dish soap offer a cheaper alternative but wash off even faster.
- Eliminating harborage: Groundhogs prefer to live near cover. Removing brush piles, tall weeds, and rock walls near the structure you are trying to protect reduces the likelihood that a groundhog will set up residence. They rarely chew on wood that is far from their burrow entrance, because spending time in the open makes them vulnerable to predators.
- Live trapping and relocation: This is legal in many states but regulated in others, and it has mixed long-term results. A vacated burrow is often reoccupied by another groundhog within weeks. If you trap, check local wildlife regulations first, and release the animal at least five miles away in suitable habitat. Some states require a permit or prohibit relocation entirely.
Ultrasonic repellent devices marketed for groundhog control have not performed well in independent testing. Groundhogs habituate to novel sounds quickly, and the devices rarely cover enough area to protect an entire yard. Mothballs and ammonia-soaked rags placed near burrow entrances are sometimes recommended online, but mothballs are toxic to pets and children, and ammonia dissipates within hours outdoors.
Protecting Garden Plants at the Same Time
Most people dealing with groundhog chewing are also losing vegetables. The same exclusion fence that keeps groundhogs from reaching wooden structures protects a garden, so a single fencing project can solve both problems. The fence needs to be tight to the ground with no gaps larger than three inches, because groundhogs can squeeze through surprisingly small openings.
Raised beds offer some protection if the sides are tall enough (at least 18 inches) and made of material the groundhog cannot easily grip and climb. Metal or composite raised beds are better than wooden ones for obvious reasons: the groundhog has less incentive to gnaw on something it cannot bite into. Placing the garden far from known burrow entrances also helps, since groundhogs tend to forage within 150 feet of home.
Some gardeners have had success planting a perimeter of plants that groundhogs dislike. Lavender, sage, thyme, and ornamental alliums (onion-family plants) are commonly cited as deterrents. Groundhogs do seem to avoid strong-smelling herbs, though a hungry groundhog preparing for hibernation may push through a lavender border to reach a row of ripe tomatoes.
Where the Name “Woodchuck” Comes From
The word “woodchuck” has nothing to do with wood. It is an English adaptation of an Algonquian word, likely from the Narragansett “ockqutchaun” or the Cree “wuchak,” both of which referred to the animal itself. English settlers anglicized the unfamiliar sounds into something that resembled words they already knew. The famous tongue twister “How much wood would a woodchuck chuck if a woodchuck could chuck wood?” plays on this false etymology, and it has cemented the idea that the animal has a special relationship with wood. In reality, groundhogs chew wood no more or less than many other large rodents. Beavers, porcupines, and even gray squirrels all gnaw on wood for similar dental reasons.
Groundhog Jaws Are Built for Power
The groundhog’s ability to chew through tough materials is not just about the teeth. The entire skull and jaw are adapted for powerful biting. Research on mandible shape across the squirrel family (Sciuridae, the broader group that includes groundhogs, tree squirrels, and flying squirrels) has found that groundhogs represent one of the extreme body plans within this family, with jaws shaped by their ground-dwelling, burrowing lifestyle.2Mammalia. Phylogeny, adaptation and mandible shape in Sciuridae (Rodentia, Mammalia) Compared to a tree squirrel, a groundhog has a deeper, more robust lower jaw with larger muscle attachment sites. This gives it a stronger bite force relative to its body size, which it uses not just for gnawing but also for digging. Groundhogs often bite through roots while excavating burrows, so their jaws serve double duty as both feeding tools and digging implements.
This robust jaw anatomy means that lightweight materials offer almost no resistance. Thin plywood, softwood trim, foam insulation board, PVC pipe, and rubber garden hoses are all well within a groundhog’s destructive capacity. If you are choosing materials for a structure you know will be near groundhog activity, harder materials fare better. Pressure-treated lumber lasts longer than untreated softwood, and metal or composite materials are the most resistant.
When Chewing Becomes a Sign of a Bigger Issue
Occasional gnaw marks on a fence post do not necessarily signal an infestation. A single groundhog passing through the area may chew something and move on. But if you are finding fresh chew marks repeatedly on the same structure, along with burrow openings within 50 feet, you likely have a resident groundhog whose territory overlaps your property. In that case, the chewing will not stop on its own, because the animal has established a home range and will continue its dental maintenance on whatever surfaces are available.
The timing of damage also matters. Groundhogs in the northern parts of their range hibernate from roughly October through February or March, so fresh chewing during those months points to a different animal entirely. Rats, mice, rabbits, and porcupines all leave gnaw marks on wood, and each has characteristic tooth-mark patterns. Groundhog incisors are wide, leaving parallel grooves roughly three to four millimeters apart. Rat teeth leave narrower, closer-together marks. Rabbit gnaw marks tend to appear higher on trunks and posts, because rabbits stand on their hind legs to feed. If you are seeing damage in winter, look at the tooth-mark width before blaming a groundhog.
Living with Groundhogs on the Property Line
Not everyone needs or wants to remove groundhogs entirely. In rural and suburban areas, groundhogs fill an ecological role as prey for foxes, coyotes, hawks, and large owls. Their abandoned burrows provide shelter for rabbits, skunks, opossums, and even foxes. If a groundhog is living at the edge of your property and not threatening a structure or garden, peaceful coexistence is a reasonable option.
The practical approach in that case is targeted protection rather than removal. Wrap the specific wooden structures you care about, fence the garden, and leave the rest alone. Groundhogs are not aggressive toward people, they do not carry rabies at high rates compared to raccoons or bats, and they rarely cause problems that cannot be solved with a roll of hardware cloth and an afternoon’s work. The chewing is a biological imperative they share with every rodent on the planet. You are not going to talk them out of it, but you can redirect it to places where it does not matter.