When a squirrel is seen vigorously working on a wooden fence, deck railing, or tree branch, it raises the question of whether it is eating the wood or simply chewing it. This common behavior, which often results in visible damage to human structures, is frequently misunderstood. The activity is a necessity for the animal’s survival, intended to wear down its teeth rather than provide nutritional sustenance. The primary diet of a squirrel consists of nuts, seeds, fungi, and buds, not the woody cellulose material of structures.
The Truth Behind Wood Consumption
Squirrels are classified as rodents, and their wood-chewing behavior is a form of gnawing, which is distinct from eating. Gnawing involves scraping or wearing away material with the teeth, while eating is for ingestion and digestion. When a squirrel works on wood, it is usually not swallowing the pieces, but rather shaving off small particles that fall away. The squirrel is not breaking down the wood for calories or nutrients, even if tiny fragments are occasionally ingested. The destruction of wooden structures is a byproduct of a biological imperative, not a sign of a starving animal seeking food.
Primary Motivations for Gnawing
The reason squirrels must gnaw on hard materials like wood is rooted in their unique dental structure. Like all rodents, a squirrel’s four incisor teeth—two on the top and two on the bottom—never stop growing. These teeth are covered in hard enamel on the front and softer dentin on the back, causing them to self-sharpen into a chisel-like edge as they wear down. This continuous growth, which can be as much as eight or nine inches per year, means that constant abrasion is necessary for survival. If the squirrel were to stop gnawing, its incisors would grow so long that they would prevent feeding and ultimately lead to starvation.
Gnawing for Secondary Reasons and Resources
While dental maintenance is the fundamental reason for gnawing, squirrels also chew wood for practical tasks related to survival and habitat modification. A squirrel may target the bark of certain trees, particularly in late winter or early spring, to access the nutrient-rich cambium layer underneath. This layer is a source of moisture and carbohydrates when traditional food sources like nuts are scarce. Gnawing also serves to create or enlarge openings into potential nesting sites, such as a hollow in a tree or a vulnerable gap in a home’s fascia board. By chewing, the squirrel can gain access to shelter and strip off wood fibers to use as soft nesting material.
Deterring Wood Chewing Behavior
Homeowners can protect their property by implementing deterrent strategies that redirect the squirrel’s natural behavior rather than trying to eliminate the gnawing instinct entirely. One effective approach involves the application of taste deterrents, which are harmless to the animal but feature an unpleasant flavor. Sprays containing capsaicin, the compound that gives chili peppers their heat, are successful because squirrels are repelled by the spicy taste. These deterrents require regular reapplication, especially after rain, to maintain efficacy.
Physical barriers provide a more permanent solution against determined chewers trying to gain entry to a structure. Covering vulnerable spots like roof vents, soffit corners, or window trim with sturdy materials, such as metal flashing or heavy-gauge hardware cloth, will prevent the squirrel from getting a purchase with its teeth. Removing secondary attractants is also an effective mitigation step, as squirrels are driven to chew wood for resources. Securing outdoor food sources, like bird feeders or pet food, and trimming tree branches away from the roofline can reduce the attraction of your home as a desirable place to gnaw.