Body: A blackish (or brownish), medium-sized, slender rat with long, naked, scaly tail; tail usually longer than head and body but not always so.
Total length, 370 mm; tail, 190 mm; hind foot, 36 mm. Weight, up to 200 g. Roof rats are largely commensals and live in close association with man. They seldom become established as feral animals as do the Norway rats. They may live near the ground, but usually they frequent the attics, rafters, and crossbeams of the buildings. They make typical runways along pipes, beams or wires, up and down the studding, or along the horizontal ceiling joists, often leaving a dark-colored layer of grease and dirt to mark their travelways. Like the Norway rat, the roof rat is largely nocturnal and only where populations are relatively high does one see them frequently in the daytime. They accept a wide variety of food items, including grains, meats, and almost any item that has nutritive value. Like the Norway rat, the roof rat is destructive to property and foodstuffs. Also, it plays an important part in the transmission of such human diseases as endemic typhus, ratbite fever, and bubonic plague.
