Roof Rats vs Norway Rats in San Jose

The short answer for San Jose homes

Across the Santa Clara Valley, the rat in your attic is almost always a roof rat. Mature fruit trees, ivy, and warm attics make San Jose neighborhoods a near-perfect habitat for them. Norway rats show up too, but you usually find them at ground level — near foundations, crawl spaces, sheds, and drains — not in the rafters.

Knowing which species you have changes where we trap, where we seal, and how long the job takes.

How to tell roof rats and Norway rats apart

• Body shape: roof rats are sleek and slender, around 6–8 inches with a tail longer than the body. Norway rats are heavier and stockier, 7–10 inches with a tail shorter than the body.
• Nose and ears: roof rats have a pointed nose and large ears that reach the eyes. Norway rats have a blunt nose and small ears half-buried in fur.
• Droppings: roof rats leave pointed droppings around 12 mm long. Norway rat droppings are blunter and a bit larger, closer to 18–20 mm.
• Where you hear them: roof rats — ceilings, attics, upper walls, after dark. Norway rats — crawl spaces, garage floors, walls near the foundation.
• Outside clues: chewed fruit and runways on fence tops point to roof rats. Burrow holes near the foundation, woodpiles, or compost point to Norway rats.

Why San Jose is roof-rat country

The South Bay is full of the things roof rats need: lemon, orange, loquat, fig, persimmon, and avocado trees, dense ivy and bougainvillea on fence lines, and warm, vented attics with easy access from overhanging branches. They travel power lines and fence tops from yard to yard, then enter through gable vents, roof-to-wall gaps, and damaged eaves.

Norway rats show up most often along older homes with deteriorated foundations, near creeks and drainage, in commercial alleys, or on properties with sheds, chicken coops, and woodpiles. They burrow into the ground next to the building and push in through crawl-space vents and slab gaps.

Control method — roof rats

• Trap along attic runways, rafters, and roof lines — not on the ground.
• Seal gable vents, eaves, roof-to-wall gaps, and pipe penetrations with steel mesh and sealant.
• Trim branches back from the roof line and thin out ivy and fence-top vegetation.
• Decontaminate soiled insulation in the attic so leftover scent does not draw the next group in.

Control method — Norway rats

• Trap at ground level — along walls, behind appliances, in garages and crawl spaces.
• Screen crawl-space vents, seal slab and pipe gaps, and reinforce garage-door sweeps.
• Collapse burrows next to the foundation after the colony is cleared so new rats do not move in.
• Address the food and harborage on the property — pet food left out, open compost, woodpiles against the house.

Not sure which one you have?

If the noise is overhead and after dark, you are almost certainly dealing with roof rats. If you see burrows along the foundation, runways through the lawn, or droppings in the garage, lean toward Norway rats. When clues point both ways, a no-obligation inspection sorts it out and shows you the entry points before any work begins.

Request a no-obligation inspection or call (408) 762-1180.