Norway ratNorway Rats

Order: Rodentia
Family: Muridae
Scientific Name: Rattus norvegicus (Berkenhout)
Color: Gray, brown or black
Legs: Four
Shape: Long
Size: 10 to 12 inches (8" body plus 4" tail)
Antennae: No
Flight: No

The Norway rat is the largest of the commensal rodents. They are thought to be of Asian origin but are found throughout the United States and the world. These rats have smaller eyes and ears and shorter tails than the roof rat.

Rats are excellent climbers and often enter a home in the fall when outside food sources become scarce. They have poor vision and are color blind, but their hearing, touch, taste and smell senses are keen. They are excellent runners, climbers, swimmers and jumpers. Norway rats will eat almost anything but prefer meat, fish and grains.

Norway rats are primarily nocturnal and live in fields, farm lands and structures. Rats are often found in woodpiles. These rodents can gain entry to a home through a hole the size of a quarter (1/2"). They typically nest indoors in basements but may be found in attics.

Rats can chew through wiring, causing fires. They also spread numerous diseases. Historically, the plague was spred by rats, transmitting the disease by fleas. Various diseases are associated with the rodents, including murine typhus, infectious jaundice, rat-bite fever, trichinosis and food poisoning.

Keep firewood stored well away from the structure. Remove debris piles. Seal any holes larger than 1/4 inch. Remove moisture and harborage sources.