Norway rats, also known as house rats, brown rats, wharf rats, sewer rats, water rats, and gray rats, are the most common rat, found in all 50 states. They are heavy bodied, 7-12 inches in length with small eyes and ears and a blunt nose. The tail is shorter than the head and body. Fur is shaggy and varies in color from reddish to grayish brown to completely black. Norway rats can weigh up to one pound. Natural habitat is outside in burrows, but they will readily live indoors in warehouses, businesses and homes. They are excellent swimmers and climbers. Rats will feed on anything but prefer food high in protein and carbohydrates.
Norway rats carry a variety of diseases that are carried in their droppings and urine. Rats will nest in attics or crawlspaces, contaminating those areas with their fecal material, creating health hazards for the occupants. They also cause damage and create fire hazards with their constant gnawing habits. Norway rats can enter homes through holes in siding, pipe conduit openings, roof lines, power or phone lines or by burrowing. They can gnaw through openings as small as half an inch. Norway rats are nocturnal with most of their activities occurring one half hour after sunset and one half hour before sunrise. Bird feeders or pet food left outside will attract rats. Signs of rats are a distinctive musky odor, gnaw marks, tracks in dusty areas, droppings or unusually agitated house pets.