Order: Rodentia

Family: Muridae

The Norway rat gnaws, eats and contaminates stored food products. Because this rodent is a common vector of diseases, it is of human health importance. This rat is found throughout the world and is believed to be of Asian origin.

Description: A Norway rat's adult body length is approximately 7-9-1/2 inches long. The fur is coarse brown with black hairs and a gray to whitish belly. The tail length is shorter than the body length and ranges from 6-8 inches long.

Biology: Adult females have between three to six litters per year averaging seven or eight young per litter. The young are blind at birth. As they mature, they have keen senses except for their eyesight. Norway rats are quite agile and good climbers, jumpers and swimmers. Rats have been known to transmit disease to humans through fleas.

Habits: Rats are nocturnal (active at night). They are cautious and tend to shy away from new objects or changes in their environment. Outside rats usually nest in burrows in the ground along rivers, streams banks, railroad embankments and near piles of rubbish. Rats are social and may have many burrows in an area. Rats can gain entry into a building through an opening as small as one-half inch in diameter. Inside, rats tend to nest in basements and the lower portions of buildings. Although Norway rats prefer fish, meats and cereal, they will eat almost anything. They have exceptionally strong teeth and have the ability to gnaw through strong materials such as plaster walls and lead pipes.