The head and body of the Norway rat will range from 7 1/2 to 9 1/2 inches. The scaly tail is 6 to 8 inches in length. Their fur is shaggy brown with some black hairs. They have small eyes and ears.
These rats are nocturnal and very cautious. They can enter a structure through an opening as small as a 1/2 inch. Indoors, they prefer to nest on the lower levels, such as a basement. Outdoors, they burrow in soil, under sidewalks, near streams and rivers, piles of garbage, etc.
They will chew through almost anything to get to food or water but they prefer meat, fish, and cereals. Adults usually live between 6 to 12 months. Generally producing 3 – 6 litters, with an average of 7 – 8 young per litter.