Roof rats typically weigh 5 to 10 ounces. They have light black to grey smooth fur on their bodies with off white to grey underbellies. They are usually about 15 inches long, and have a long hairless tail that can be about 14-1/2 inches long. Unlike Norway rats, their tails are longer than their heads and bodies combined. They have large ears and eyes (typically larger than those of the Norway rat) and have a pointed nose.
As their name indicates, roof rats usually nest high above ground in trees, tall overgrown shrubs, or dense vegetation such as ivy. Roof rats are excellent climbers and often access homes by running along tree branches, cables or wires. In buildings, they typically nest in the upper part of structures in enclosed or elevated spaces such as attics, walls, false ceilings, and cabinets. They are very agile and can squeeze through openings only 1/2-inch wide. Roof rats can climb down to a food source.
Roof rats routinely travel up to 300 feet for food. They often can be seen at night running along overhead utility lines or fence tops. They have an excellent sense of balance and use their long tails to steady themselves while traveling along overhead utility lines. They move faster than Norway rats and are very agile climbers, which enables them to quickly escape predators.
Given their history of causing damage (gnawing through wiring, food contamination, etc.) and health problems (vectors for salmonella, murine typhus, etc.), it is important that homeowners understand how to identify and businesses protect themselves from these costly pests.