Homeowners often wonder if squirrels are repelled by strong odors like mothballs, believing the pungent smell is an effective solution for keeping them away from gardens or attics. While squirrels, like many animals, dislike intense smells, the idea that mothballs are a successful deterrent is a persistent misconception. This belief often leads to using a product in a way that is both ineffective and dangerous.
The Truth About Mothballs and Squirrels
Squirrels generally dislike the smell of mothballs, but this aversion does not translate into long-term, effective deterrence. While the vapors may cause initial discomfort, the strong drive for food or shelter often outweighs this mild annoyance. Squirrels are highly motivated to secure a safe nesting site or access an available food source.
Once a squirrel identifies an attic or wall void as a suitable location, scattered mothballs are unlikely to prevent nesting. The active chemical in mothballs is designed to work in a sealed container, but it rapidly dissipates when placed in open areas like a yard or attic. The vapor concentration quickly drops below the level needed to be truly repellent.
Squirrels are also intelligent and adaptable; they may simply move the mothballs or find a way around the placement, continuing to access the property. Using mothballs creates a toxic hazard that fails to address the underlying attraction issue.
Toxicity and Regulatory Status of Mothballs
Mothballs contain high concentrations of active ingredients, typically naphthalene or paradichlorobenzene. These chemicals are highly toxic fumigants regulated as pesticides by the Environmental Protection Agency (EPA). Their toxicity poses a severe risk to squirrels, pets, children, and the environment.
Ingestion of even a single mothball can cause serious health issues, including liver or kidney damage and hemolytic anemia, which destroys red blood cells. Inhalation of the vapors can cause headaches, nausea, and respiratory problems, especially in enclosed spaces like an attic.
The EPA strictly mandates that mothballs only be used to control clothes moths and their larvae within tightly closed containers. Using mothballs outdoors, scattering them in a yard, or placing them in an open attic to repel animals is considered an illegal “off-label” use under federal law. This misuse allows toxic chemicals to contaminate the soil and groundwater.
Humane and Effective Squirrel Deterrents
Exclusion is the most effective and humane method for managing squirrel problems. The primary goal is to identify and seal all potential entry points into the home, such as gaps around roof vents, chimneys, or fascia boards. Use durable materials like half-inch galvanized hardware cloth to seal openings, as squirrels can easily chew through softer materials.
For gardens, an EPA-approved animal repellent can be used as a temporary measure. Repellents containing capsaicin or specific predator urine scents are commercially available. These products create an unpleasant taste or smell that encourages the animal to forage elsewhere. Trimming tree branches at least six feet away from the roofline also removes common access routes, making the house less appealing as a potential shelter.