The Norway rat is native to East Asia and is a rat found in almost any lowland area inhabited by people. It favors wet environments, sewers, and garbage dumps, is a good swimmer, and builds nests in sewer pipes or holes in the ground. Its fur is brown, its ears and tail lack hair, and it is omnivorous, eating reptiles, birds, small mammals, and plants. It is crepuscular to nocturnal and terrestrial, forms social groups, has a high reproductive rate, and breeds year-round. The IUCN classifies it as Least Concern.