Norway Rat


Actual Size: 7″

Characteristics: The Norway rat is brown with a blunt nose and relatively small ears. Droppings are ¾”, capsule shaped with blunt ends.


  • Norway rats are most active at night.
  • They typically nest in burrows or pre-existing holes outdoors.
  • They gain access through quarter-sized holes, and beneath exterior doors.

Norway rats are stocky, heavy bodied rats and are larger and more aggressive than their cousin the roof rat or black rat. Found throughout the United States, Norway rats are commensal rodents, living near and dependent on the human habitat for survival. Norway rats will eat almost anything, but prefer cereal grains, meats, fish, nuts, and some fruits. Like most rodents, Norway rats are most active an hour after sunset and just before dawn. The gnawing activity of Norway rats can cause considerable damage to homes, gardens and structures. Norway rats are carriers of serious diseases, including jaundice, rat bite fever, and salmonella.

Norway Rat Habitat

In general, Norway rats are ground burrowing animals and construct burrows that are 2 to 3 inches in diameter and up to 6.5 feet in length. Burrows are constructed outdoors along foundations and gardens. Norway rats are nocturnal and will enter homes at night in search of food, returning back to their burrow. If nests are found inside homes, they are typically in basements and crawl spaces. If a population is large, Norway rats will nest in upper areas of a home or structure.

Norway Rat Behaviors, Threats or Dangers

Norway rats can damage foundations, slabs, garden crops and plants as they burrow and gnaw to find food and shelter. Inside homes, Norway rats may cause extensive damage when nesting in walls and attics. Accounts of rodents starting fires through the gnawing of electrical wires have been widely reported. Chewed, exposed wires inside walls can spark, causing interior walls to catch fire. When foraging for food, these rats consume and contaminate food meant for humans, pets and livestock. Salmonella, leptospirosis, and rat bite fever are among the dozens of diseases spread by Norway rats.

Norway Rat Prevention

To prevent a Norway rat infestation, eliminate their access by trimming back trees and shrubs that come in contact with your home. Remove unwanted vegetation such as grass clippings, leaf litter and weeds. Store dry food items in airtight containers and keep tight fitting lids on trash bins. Outdoors, clean up around bird feeders or use a “no-waste bird food”. Seal cracks around utility cables, outdoor vents or pipe work with steel wool or silicone-based caulk.