Norway Rat


Actual Size: 16” long including the tail

Characteristics: Robust bodies. Typically grayish-brown can be reddish-brown to blackish.

Habitat: Dig 6.5 feet long burrows along property lines and gardens. Will nest in basements and crawl spaces of homes.


  • Sometimes called a sewer rat or a brown rat
  • Tails are hairy and shorter than their head and body combined
  • Known to be more aggressive than other types of rodents

Norway Rats in The North Bay and East Bay Area

Norway rats are one of the more aggressive types of rodents. They have bigger, stockier bodies than the roof rat. Norway rats are often in residential and city areas because they depend on 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. With incisors that never stop growing, the Norway rat can cause damage to homes and structures with their gnawing habits. The biggest concern about Norway rats is their ability to spread disease, including jaundice, rat-bite fever, and salmonella.

Norway Rat Environment

Norway rats will either build their own burrows or use ones left behind by past rodents or animals. The burrows they construct are 2 to 3 inches in diameter and up to 6.5 feet in length, and are usually build outdoors beside 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, such as in an attic.

Norway Rat Habits & Threats

Because Norway rats are more aggressive, they can cause more damage. These rodents are known to 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.

If you have a Norway rat infestation in your Bay Area property, contact your local rodent control experts!