Norway Rats: Essential Facts and Control Measures

When most people think of rats, they often think of garbage and disease. In our modern-day of medicine and technology, rats pose significantly less of a threat to humans. Still, they are not an animal you want to share your house with.

The Norway Rat can be found all over the world. Believed to have originated in Asia, the Norway rat most likely stowed away on ships departing from Asia and made their way to the US around the 1700s. 

Norway rats are often known as sewer or street rats. If you believe you are experiencing a Norway rat infestation, contact Environmental Pest Management today.

Norway Rat

Norway Rat 101

What do Norway rats look like?

Norway rats are brown with scattered black hairs. They have a white or gray underside and a long, thick tail that they can use to balance on their hind legs.

Speaking of legs, the Norway rat has four short and stubby ones. They are usually long and heavy bodies. They have a short, blunt muzzle and small black eyes. They generally have poor vision and, unfortunately for them, are colorblind. 

The Norway rat can reach lengths of seven to 10 inches long. Their tails are usually shorter than their bodies.

Where do Norway rats live?

Norway rats are very social. They usually build their nests or shelters in close proximity to other Norway rats. For you as a homeowner, that means that if you see one rat, there are likely many others that you cannot see. 

When they build their homes, they typically have one entrance and at least one emergency exit, or bolt-hole. This secondary exit is usually well hidden. 

When found outdoors, these rat homes are usually found in farmlands, fields, and sparsely populated structures, such as barns, garages, or sheds. They can also be found burrowing in riverbanks and the edges of streams. 

Norway rats generally only enter human homes when the weather starts to turn colder, and food is scarce. Norway rats can squeeze themselves through almost any hole. As long as it is the size of a quarter, a rat can fit into it. 

Once the Norway rat has entered a house, they typically find a home in attics, basements, or cellars. They prefer areas with lots of piles of debris in which they can hide. Usually, they stay away from densely populated parts of your house as they are more scared of you than you are of them. 

They generally prefer to stay on the lower levels of your home, but they will venture higher if they need to. 

Norway rat in the garden between grass blades

What and when do Norway rats eat?

Norway rats are nocturnal. Their peak foraging hours are dusk and dawn, but they typically eat continually throughout the day. They are hoarders, and they usually carry the food they forage to a safe place to eat later. 

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Norway rats are very adaptable, and they will eat almost anything. They are omnivores, but they prefer meat and fish with a grain supplement. Think of Norway rats as followers of the Paleo diet. But, Norway rats are not picky. In fact, they have been known to binge on dog food when it is available. 

Beyond food, Norway rats will gnaw through almost anything. To obtain a food source, they will work their way through the plastic, metal, and even lead pipes. They are real survivalists and will do whatever they need to live. 

Norway rats have good memories, and they remember when they eat a food they dislike. They are creatures of habit and will avoid that food in the future. Conversely, if they find a food source that they particularly like, they will return again and again. 

Norway rats always need a source of water beyond the food they eat. They tend to follow the same paths that they always take. They use their whiskers to feel the way. 

Norway rats prefer to find their food source within 25 to 100 feet of their nest. If they need to, though, they will travel upwards of 150 feet to find the food and water they need. 

How do I know if I have a Norway rat infestation?

Luckily, you will find many visible signs that your home is infested with these unwanted pests. Some of them are:

  • Gnaw marks throughout your house. 
  • Look for new bite marks or holes that are rough. 
  • Older bite marks are smooth and greasy from wear.
  • Check for capsule-shaped droppings in areas of your home that Norway rats are likely to reside and hide.
  • Check the lower traffic areas of your house for footprints, greasy and dark rub marks, oily fur pathways, burrows, food caches, or damaged or chewed on food containers. 

Once you notice any of these signs, your home has likely been invaded by these pesky critters. 

norway rat on wooden deck

How do I prevent Norway rats  from entering my home?

You want to do everything you can to prevent Norway rats from infesting your home. The reproduce relatively quickly, so a small infestation can turn into a large one rather quickly. The female Norway rat can give birth to 3 to 6 litters a year, so prevention is critical. 

Keep the area surrounding your home free of piles of wood and debris. Seal any holes on the exterior of your home with steel wool to block potential entry. 

Eliminate the Norway rat’s water source by repairing any leaky pipes. Take steps to limit the food supply by adequately sealing your food boxes and containers. Avoid contamination from any bacteria or virus those critters may transmit to your food. 

If you are worried about rat infestations, make sure your outdoor garbage cans are securely sealed. Make sure you are continually taking the trash and debris out of your house to eliminate temptation.

If you suspect you have a Norway rat infestation on your hands, it may be time to call in a professional. The caring experts at Environmental Pest Management care about your home and the safety of your family. Let us take care of your critters in an environmentally friendly way.