Norway Rat

Profile

Scientific name

Rattus norvegicus

Identification

Coarse brown fur with a gray belly, small ears, blunt nose and a bicolored tail shorter than the head and body.

Typical size

Body about 7-10 inches with a shorter tail.

Behavior

Burrows, follows established ground runways, and is wary of new objects. Nests below grade rather than in attics.

Habitat

Burrows along foundations and slabs, under decks and sheds, in sewers and along canals.

Diet

Garbage, grain, pet food, meat scraps and virtually any food waste.

Lifecycle

Prolific breeder with several litters per year; colonies grow where food and harborage persist.

Why it matters

Norway rats contaminate food and surfaces, damage structures and utilities, and carry disease organisms. Use CDC cleanup guidance for contaminated areas.

DIY considerations

Filling burrows without removing food and harborage simply relocates the colony a few feet.

Professional considerations

Programs combine exterior device placement, burrow work, exclusion at ground level and documented sanitation findings — especially important for food service and multifamily properties.

Signs of activity

• Burrow openings two to four inches wide along foundations or under structures
• Blunt-ended droppings near trash and feeding areas
• Smooth runways worn through vegetation
• Gnawed door corners and utility penetrations at ground level

Prevention

• Keep dumpster and trash areas clean with closed lids and clean pads
• Remove ground harborage: debris piles, unused equipment, dense low vegetation
• Seal ground-level gaps and install rodent-resistant door sweeps
• Correct drainage and eliminate standing water and food waste outdoors

Sources

• CDC — Rodent control and cleanup
• US EPA — Rodenticides and rodent control