The Norway rat is the largest of the commensal rodents and the most common commensal rat in the temperate regions of the world. It not only damages/destroys materials by gnawing, eats and contaminates stored food, but it is also of human health importance as a vector or carrier of diseases.
Adults’ head and body length are about 7-9.5” long, tail length being 6-8” long. Fur is coarse, shaggy, brown with scattered black hairs, with underside grey to yellowish white.
They are good runners, climbers, swimmers, and jumpers. Rats are primarily nocturnal in habit and they are cautious. Although they constantly explore their surroundings, they shy away from new objects and changes. Outdoors, Norway rats prefer to nest in burrows in the soil along railroad embankments, stream/river banks, piles of rubbish, under concrete slabs, etc. Indoors, Norway rats usually nest in basements and the lower portions of buildings in piles of debris or merchandise as long as it is not disturbed. Although they prefer the lower levels of buildings, on occasion they may be found in attics, on roofs, and in other high places.
Norway rats prefer meat, fish, and cereal, although they will eat almost anything as they are opportunistic feeders. They will gnaw through almost anything to obtain food and/or water, even plastic or lead pipes.