Norway rats are a common threat to the food processing, grocery, pharmaceuticals, and food service industries, but can be incredibly difficult to control. Also known as sewer rats, they damage goods, contaminate surfaces, and put health standards at risk, making them a real danger to production and processing facilities. Accurate Norway rat identification is essential to limit business disruption and support rodent control strategies. Knowing what to look for helps to stop infestations before they spread, potentially leading to health code violations.
Color: Gray, brown or black
Legs: 4
Shape: Long
Size: 10-18 inches including tail
These rats are large, heavy-bodied rodents, measuring up to 9½ inches in body length and a tail that adds several inches more. Their fur is typically coarse and brownish-grey, with a paler underside.
Norway rats are opportunistic feeders and will consume almost anything available, including garbage, grains, meat, and fish. They're mostly nocturnal and tend to stay close to their nesting sites when foraging. They commonly enter buildings through gaps in foundations, broken drains, or openings around pipes and utility lines, and they'll follow wall voids or crawl spaces to move through a structure.
Due to their diet and environment, these rats can pose serious health and property risks. They can transmit diseases such as leptospirosis and salmonella through their droppings, urine, and bites. They also gnaw on wiring, insulation, and structural materials, increasing the risk of electrical fires and costly damage.
Norway rats prefer to nest at ground level or below, commonly burrowing under buildings, along fence lines, or beneath debris and woodpiles. They need access to food and water to survive and are most commonly found in urban areas, warehouses, restaurants, and residential properties.
Seal any cracks or gaps around the foundation, pipes, and utility entry points to block potential access. Keep garbage in tightly sealed containers and avoid leaving food waste exposed. Remove clutter, woodpiles, and debris from around the building, as these provide ideal nesting sites. Fix any leaking pipes or drains, since Norway rats are always in search of a reliable water source
Adult Norway rats typically measure between 13 and 18 inches in total length, with the tail accounting for less than half. Males tend to be slightly larger than females, and size can vary based on available food sources and habitat conditions.
They’re commonly found in basements, storage rooms, alleys, and around dumpsters. In urban areas, they may live in sewers, giving rise to the term sewer rat. Indoors, they prefer dark, cluttered spaces where they can remain hidden and close to food and water.
To help prevent an infestation, seal exterior openings larger than 1/4 inch, and store food and waste in secure containers. Eliminate standing water and clear away outdoor clutter. For reliable, long-term protection, it’s best to work with experts who offer rodent prevention help backed by professional inspection and exclusion methods.
Norway rats are opportunistic feeders that eat a wide variety of foods, including grains, fruits, vegetables, meat, and garbage. They're also attracted to pet food, birdseed, and any accessible food sources around homes and businesses.
Norway rats are large, stocky rodents with thick bodies, blunt noses, and small ears. They typically have brown or gray fur, lighter bellies, and short, thick, scaly tails that are shorter than their body length.
Keeping your property clean, sealing food in airtight containers, and eliminating clutter can help deter Norway rats. However, professional rodent control is the most reliable way to repel and remove these pests long-term.