Signs of a Rat Infestation
Rats are larger, smarter, and more cautious than mice — which means most homeowners notice the damage before they ever see a rat. If you spot any of the signs below, call a professional immediately. Rat infestations grow fast and rarely fix themselves.
1. Large, dark droppings — Rat droppings are 12-19 mm long (about the size of a raisin) — far bigger than mouse droppings. You’ll find them along walls, near food sources, in basements, attics, and storage areas.
2. Loud scratching, gnawing, or scurrying — Rats are heavy. You’ll hear them moving in walls, attics, ceilings, or above drop ceilings, especially at night. The sound is louder and more deliberate than mice.
3. Heavy gnaw marks — Rats chew through wood, drywall, soft plastic plumbing, electrical conduit, and even soft concrete. Look for fresh, splintered tooth marks on baseboards, doors, attic beams, and stored items.
4. Greasy rub marks along walls and pipes — Rats follow the same paths every night, and the oils in their fur leave dark, smudgy streaks along baseboards, joists, and pipe insulation. These marks are a near-certain sign of an active runway.
4. Burrows around the foundation or yard — Norway rats dig burrows 5-8 cm wide near foundations, garbage areas, decks, sheds, and compost bins. Multiple burrows = an established colony.
5. A strong, ammonia-like smell — Rat urine has a pungent, persistent odour. If you smell it in a basement, garage, attic, or commercial back-of-house area, the colony is active and close by.
6. Footprints and tail drag marks — In dusty areas (basements, attics, storage), rats leave 4-toed front-paw and 5-toed back-paw prints — often with a thin tail drag line down the middle.
7. Pet behaviour changes — Dogs and cats fixated on a wall, vent, ceiling, or appliance are usually hearing or smelling something you can’t. Trust the pet.
