The fastest useful split
Vertical location is the strongest household clue: Norway rats favor ground and lower levels; roof rats concentrate signs above.
Do not rely on a single color match. Start with scale and physical form, then check where the sign accumulates and whether a companion clue supports one candidate over the other.
| Feature | Norway rat | Roof rat |
|---|---|---|
| Route | Ground and basement | Roofline and attic |
| Droppings | Thicker, often blunt | Slender, more pointed |
| Entry | Burrow or lower gap | Roof gap or branch route |
| Noise | Lower walls/floors | Upper walls/attic |
Map every sign by height before choosing a species label.
Roof access, sewers and heavy contamination should be handled professionally.
Open safety guidanceCheck each full evidence profile
Norway rat
Rattus norvegicus
Large thick droppings, broad gnawing and lower-level routes near foundations, drains or burrows.
Roof rat
Rattus rattus
Slender rat-scale droppings and nighttime movement in attics, rafters or elevated routes.
Why a visual match can fail
Scale can be distorted by a close-up photograph, loose material may be moved by cleaning or airflow, and old evidence can change color or texture. A reliable conclusion uses multiple observations that point in the same direction and preserves contradictory details instead of forcing a match.