Norway Rats
Norway rats cause disease and widespread damage.


The Norway rat is known by many other names including the brown rat, sewer rat, wharf rat, barn rat, house rat, gray rat, Norwegian rat, and street rat.  This rat is slightly larger than that of the roof rat and is commonly found throughout Pennsylvania and New Jersey.


Including its tail, a Norway rat can grow to be 16” in length. It is a stocky rodent that can weigh up to a pound. Males grow larger than females, and the rat is covered in dark grey fur with the exception of a white underbelly. The fur is coarse and is absent along the rat’s tail and ears. It has a somewhat rounded nose, and small eyes and ears.


Norway rats are omnivorous creatures that will eat most anything that is available to them. They favor nuts, fruits, roots, leaves, and seeds, and grains, however, they will also eat mice, fish, birds, and meats and carbohydrates that have been left behind by humans. These rodents can consume approximately 1/3 of their body weight in one day.


Natural burrowers, Norway rats will create their nests outside in woodlands and fields, as well as in dumpsters and in sewers. If they enter a home or establishment, they are often found in wall voids, beneath concrete foundations, in basements, and anywhere else debris or garbage has been left behind. Norway rats are fond of nesting in areas that are not often disturbed, and this might be in long-abandoned storage spaces, underneath piles of trash, and in piles of stacked wood.


Norway rats are responsible for many health and property concerns. They are vectors of many diseases that can cause severe illness, including death in humans. And, because one of their main activities is to gnaw through materials to make their nests, they can destroy items like electrical wiring, documents, furniture, walls, doors, floors, pipes, and building foundations. Rat burrows can be as much as 10” in diameter and 12-18” in length.


These rodents are nocturnal, and generally search at night for food. When foraging, they have been known to travel up to a 150’ radius within the location of the nest. They reproduce throughout the year, but mate more often during the summer months. Females can give birth up to seven times a year, with each litter consisting of 8-12 offspring. Norway Rats live to be about two years old, and are able to reproduce at the age of three or four months.


The presence of Norway rats in a home or office environment can be extremely problematic for humans. Although rat bites and scratches are rare, these rodents will do so if they feel threatened. A scratch or bite can result in rat-bite fever, a disease which causes vomiting, fever, and skin inflammation.

Humans may also contract such diseases as lymphocytic choriomeningitis, bubonic plague, hantavirus, and salmonella through food contaminated by rat feces and urine or by inhalation or handling of droppings.  Additionally, Norway rats may carry lice, fleas, ticks, and mites.


It is likely that a homeowner or business owner may never see a Norway rat outside of its nest during daylight hours. That is why it is important to look for signs that there is a nest nearby. These signs include:

• Gnaw (teeth) marks in various materials such as wood, plastic, upholstery, plastic, soft metals, etc.
• Audible squeaking and gnawing sounds coming from inside a wall void.
• The presence of rat droppings. In the case of the Norway rat, droppings are ½”-3/4” long and have blunt ends.
• Clear paths where Norway rats scamper. Vegetation will be packed down, and inside, dust or dirt will be cleared away where the rats routinely track through.
• Grease marks left behind near the rat trails. Rats produce an oily substance in their fur.
• Holes that have been gnawed by rats. These holes will be about 2” in diameter and have irregular edges.


Preventing a Norway rat infestation is the first step toward maintaining a clean, pest-free environment in general. However, if an infestation exists, due to health and property concerns and potential damage, it is important to get in contact with a local pest control service provider. Below are some means to prevent a Norway rat infestation:

• Norway rats are particularly fond of pet food. Never leave pet food unsealed, and be sure pet food is not left out.
• Metal garbage cans are mostly impervious to Norway rats, and so these should be utilized as opposed to the plastic style garbage can.
• Be sure all pantry items are sealed tightly or in Mason jars or metal containers.
• Maintain regular garbage pickup.
• Trim all shrubbery and vegetation away from the home or building. Norway rats are excellent climbers and can gain easy access this way.
• Plug up any entryway into the building that is more than ¼” in size with mesh or caulk.
• Remove any “clutter” items such as newspaper, cardboard, and excess material that Norway rats can utilize for their nests.


Determining the difference between a mouse and a rat is a homeowner’s main dilemma where extermination is concerned.  That is because species identification can play a crucial role in successfully eliminating a rodent problem.

Additionally, the impulse to simply set a couple of mouse traps is common when mice are seen by property owners. Unfortunately, this course of action is not effective in the event of an infestation. Traps alone may be able to eliminate a few individuals, but large numbers of mice typically require the services of a rodent control professional.

A licensed rodent exterminator has a variety of techniques to end the infestation. This will include methods of excluding rodents from re-entering the building as well as traps and chemical control. With all of these precautions, it is possible to return a home or office to a safe and hygienic state.

If you suspect a rodent control issue, call the professional team of licensed exterminators at SafeGuard Pest Control, LLC today. We can determine if you have a mouse or rat problem in your Yardley home or office, and then proceed to implementing the best, most effective treatments. 


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