Roof rats: the climbers living in your citrus and attic.

Identifying roof rats

Rattus rattus

Roof rats are sleek, agile rodents with large ears, a pointed nose and a scaly tail that is longer than their head and body combined. They are usually dark brown to black with a lighter belly. Their droppings are about half an inch long with pointed ends.

As the name suggests, they live up high. Roof rats run along block walls, utility lines and tree branches, then get onto the roof and into attics through gaps at the eaves, roof vents, tile openings and plumbing penetrations. They are active at night and cautious of new objects, which is one reason they can be hard to catch.

Citrus is a big draw. Roof rats eat fruit right on the tree, often leaving hollowed-out rinds hanging from the branches. Overgrown palms with uncut fronds, bougainvillea and oleander hedges give them cover, and pet food, bird seed and fallen fruit keep them fed. Once a home has a food source and a nesting spot, they stay.

Why they matter

Roof rats chew constantly. In attics they damage insulation, ductwork and wiring, and chewed wires are a real fire concern. Their droppings and urine contaminate stored items and can spread disease, and fleas and mites travel with them. Do not handle droppings or nesting material with bare hands, and avoid stirring up dust in heavily soiled areas.

Signs of activity

• Scratching or running sounds in the attic or walls at night
• Hollowed-out oranges or grapefruit still hanging on the tree
• Pointed droppings in the attic, garage, pantry or along block wall caps
• Gnaw marks on wiring, boxes, irrigation lines or pool equipment
• Greasy rub marks along beams, pipes or the top of walls they travel

Prevention tips for Arizona homes

• Pick ripe citrus promptly and clean up fallen fruit every day or two
• Trim trees and shrubs back from the roof and keep palms skinned of dead fronds
• Screen roof and gable vents and close gaps at tile edges, eaves and pipe penetrations
• Store pet food and bird seed in sealed containers and bring pet bowls in at night
• Keep the garage door closed and seal the gaps around it
• Clear stored clutter in garages and sheds so rats have fewer places to nest

When to call a pro

If you hear them in the attic, the rats have already found a way in. Bryce inspects the roofline and attic, sets traps where they actually travel, and shows you which openings need to be sealed so the problem does not start over with the next group.