Norway Rats | Pest ID & Control Guide
Quick Facts About Norway Rats
Norway rats, also called brown rats, are large, heavy-bodied rodents that burrow in the soil and move into the lowest levels of buildings. They’re the most common rat in Tennessee cities and farms alike.- Size: About 7 to 9 1/2 inches long, plus a tail that’s shorter than the head and body
- Weight: Up to about a pound
- Color: Brown to grayish-brown with a lighter gray belly; coarse, shaggy fur
- Features: Blunt snout, small ears, and small eyes
- Droppings: About 3/4 inch, capsule-shaped with blunt ends
- Where they live: Burrows along foundations and in crawl spaces, basements, and lower floors
What Do Norway Rats Look Like?
Norway rats look chunky and powerful compared with roof rats.Norway Rats vs. Roof Rats
- Body: Norway rats are heavy and thick; roof rats are slender.
- Tail: A Norway rat’s tail is shorter than its head and body. A roof rat’s tail is longer.
- Head: Norway rats have a blunt nose and small ears. Roof rats have a pointed nose and large ears.
- Where they live: Norway rats burrow and stay low. Roof rats climb and nest high.
See our roof rat guide.
Signs of Norway Rats
- Burrows: Holes about 2 to 4 inches wide along foundations, under slabs, sheds, and woodpiles, often with smooth, packed dirt
- Droppings: Large, blunt-ended droppings along walls and near food
- Runways: Worn paths in grass or dirt along fences and walls
- Grease marks: Dark smudges along walls, pipes, and entry holes
- Gnawing: Large gnaw marks on wood, plastic, and even soft metals
- Noises: Scratching or scurrying in crawl spaces and lower walls at night
Where Norway Rats Live In and Around Your Home
- Crawl spaces and basements
- Along foundations, under porches, decks, and slabs
- Garages and sheds, especially with stored feed or seed
- Around trash cans, compost, and pet food
- Near creeks, drainage ditches, and storm drains
- In lower wall voids and around plumbing
Health & Property Risks
Health Concerns
Norway rats can spread leptospirosis through their urine, contaminate food with Salmonella, and cause rat-bite fever through bites or scratches. They can also carry fleas and mites.
Property Damage
They gnaw through wood, plastic, drywall, and wiring, and their burrows can undermine slabs, walkways, and foundations. They also contaminate far more food than they eat.
How to Prevent Norway Rats
- Seal openings: A rat can get through a 1/2-inch gap. Use hardware cloth, metal flashing, or concrete to seal foundation gaps and vents.
- Remove food: Store pet food, feed, and birdseed in metal containers, and clean up fallen fruit and spilled seed.
- Manage trash: Use tight-fitting lids and keep bins away from the house.
- Eliminate cover: Clear debris, stacked lumber, and dense vegetation along the foundation.
- Fix leaks: Rats need water daily.
When to Call a Professional
Rats are wary of new objects, so they often avoid traps that aren’t placed and baited correctly, and they breed fast. If you see burrows, droppings, or a rat in daylight (a sign of a large population), call a professional. Treatment usually combines exclusion, trapping, tamper-resistant bait stations, and burrow treatment, followed by monitoring. See our rodent control services or commercial rodent control.
Frequently Asked Questions
How big are Norway rats?
Adults are about 7 to 9 1/2 inches long, plus a tail that’s a bit shorter than the head and body, and they can weigh up to about a pound.
What’s the difference between a Norway rat and a roof rat?
Norway rats are heavy-bodied with a blunt nose, small ears, and a tail shorter than the body, and they burrow and stay low. Roof rats are slender with large ears and a long tail, and they climb and nest high.
What do Norway rat burrows look like?
Holes about 2 to 4 inches wide along foundations, under slabs, sheds, and woodpiles, often with smooth, packed dirt around the opening.
Is seeing a rat during the day a bad sign?
Often, yes. Rats are mostly active at night, so daytime sightings can mean a large population competing for food.
Can Norway rats get into a house through a small hole?
Yes. They can squeeze through a gap about 1/2 inch wide and will gnaw to enlarge smaller openings.
