What is a Norway rat, and what does it look like?

Norway rats, also known by their scientific name, “Rattus Norvegicus,” are among the most widespread pests anywhere. As their name might suggest, they are originally from northern Europe, but they found their way across the world by following human migrations and hitching rides on commercial ships throughout the ages. The large population of rats on ships was such a big problem that sailors would often bring a handful of cats with them, letting them loose on the vessels to reduce and control the Norway rat population on board, as the rodents could thrive and reproduce during long seafaring trips, sheltered in the guts of the ships. Their distinctive grey fur and bare-looking tails are particularly striking and distinctive for this species.

What are the signs of a Norway rat infestation?

Rats are quick, so they can run and hide before humans can take a glimpse of them. They are not very active throughout the day, but they often hustle during the night when they roam through garbage bins or scavenge the area for food and water. In some cases, rats can make their way into homes through the drainage system and climb out of toilet seats.

Rat droppings are highly recognizable; they can be found in the corners of rooms, as well as in cupboards and under tables. In addition to that, it might be possible to notice signs of chewing on food packaging, as these rodents can easily bite through many materials. Many homeowners try to seal cracks and crevices that might allow rats to enter, but rats can chew through most material, with the exception of steel wool.

Signs of a rat infestation can include:

Droppings:
Norway rat droppings are dark, blunt-ended, and about 3/4 of an inch long. Finding these pellet-like droppings in cabinets, along baseboards, or near food sources suggests active rodent presence.

Gnaw Marks:
Norway rats have strong teeth and will chew on wood, plastic, and even softer metals. Look for fresh gnaw marks on baseboards, door frames, wiring, or stored goods.

Burrows and Runways:
Outdoors, Norway rats often dig burrows near building foundations, under shrubs, or under woodpiles. Indoors, they travel along walls and behind appliances, leaving well-worn “runways” where dust or dirt is cleared, and surfaces may show oily rub marks from their fur.

Nocturnal Activity and Sounds:
Scratching, scurrying, or squeaking noises heard at night—especially from walls, ceilings, or under floors—can indicate rats are active after dark.

Grease or Rub Marks:
Rats leave behind dark, greasy marks along commonly used travel routes. These marks appear where their bodies brush against walls or beams.

Nests and Shredded Materials:
Finding nests made from shredded paper, fabric, or insulation in hidden areas (like the back of drawers or secluded corners) often suggests a rat presence.

If you notice one or more of these signs, consider contacting a professional for proper identification and control methods to prevent further infestation and potential health risks.

Are Norway rats dangerous? Do Norway rats carry disease?

Norway rats are dangerous to humans. They are commonly very shy and won’t attack if unprovoked, but they can bite people. Their bite can carry rabies or other diseases and infections. In addition to that, rat paws can spread bacteria and germs, so they have the ability to contaminate homes and commercial spaces. Their droppings can also carry germs and bacterial and viral agents.

Rat protection is included with our Pest Protect 365 Premium and All-Inclusive home services. If rats are entering your home, our Exclusion Service can keep them out for good with repairs so they don’t come back.

Call us today for a free, no-obligation inspection if you suspect rats in your home or business.