Signs of Roof Rats in the Attic Roof rats enter homes by jumping onto rooftops from utility lines or branches. Even nickel-sized holes along attic vents, pipes, or walls are big enough for the pests to squeeze through. Once inside, roof rats gather in closed, rarely used spaces like attics to nest. Homeowners with rodent problems may notice lines of small, dark droppings and rub marks from the pests' greasy fur along baseboards and walls. Doors, ledges, roof eaves, and support beams may also show signs of gnawing. In addition, roof rats often keep residents up at night with loud squeaks and scratching inside walls or ceilings. Damage Property damage caused by roof rats can add up quickly. In attics, the pests tear up insulation to build their nests and chew on the casing of electrical wires and pipes. They also find paths down to kitchens and pantries, where they eat and contaminate food. This is the way roof rats typically spread diseases like plague, salmonellosis, leptospirosis, rat-bite fever, and typhus to humans. Infested homes also need to be screened for any added pests the rodents may carry, such as mites and ticks. Prevention & Removal To prevent roof rats, check for damaged attic vents, louvers, vent pipes, or tiling that could allow the pests to enter. Cover any openings 1/4 inch in diameter or more with hardware cloth. Keeping trees and ivy trimmed and away from rooftops, fences, or utility poles also makes it more difficult for the rodents to climb onto roofs. To get rid of roof rats that are already inside, avoid using poisons. The smell of carcasses in hard- to -reach areas can fill the whole house. Traps work well, though picking the right size, location, and bait is key. For fast, effective removal, call local wildlife control professionals.