Why do mice eat insulation? - briefly
Mice gnaw insulation because it is soft enough to shred for nest construction and provides necessary wear for their continuously growing incisors. The material also contains protein‑rich fibers that fulfill a dietary requirement.
Why do mice eat insulation? - in detail
Mice gnaw insulation primarily because it satisfies two biological needs: dental maintenance and nutritional intake. Their continuously growing incisors require constant abrasion; the fibrous texture of most insulating materials provides an effective substrate for wear. Simultaneously, many forms of insulation contain organic substances—cellulose, cotton, or protein‑rich binders—that can be ingested as a source of protein, carbohydrates, or minerals.
The attraction varies with insulation type:
- Cellulose batts: Made from recycled paper treated with fire‑retardant chemicals, they contain cellulose fibers that mice can chew and partially digest, gaining modest caloric value.
- Fiberglass: Although composed of glass fibers, the surrounding binding agents often include starches or adhesives that mice may ingest. The material also offers a soft, chewable surface.
- Foam board and spray foam: These products include plastic polymers and sometimes added flame‑suppressants containing nitrogen or phosphorus compounds, which can provide trace nutrients or salts.
Beyond nutrition, insulation offers a warm, protected environment ideal for nesting. The material’s ability to retain heat creates a microclimate that reduces energy expenditure for thermoregulation. Additionally, the dense structure shields mice from predators and environmental disturbances, encouraging colony establishment.
Damage resulting from gnawing can compromise thermal efficiency, increase energy costs, and create entry points for other pests. Effective mitigation includes sealing gaps larger than 1⁄4 inch, installing steel‑wool barriers, and employing traps or bait stations in proximity to suspected activity. Regular inspection of insulation layers—particularly in attics, crawl spaces, and wall cavities—helps detect early signs of infestation, such as shredded fibers or droppings.