Norway Rat

Also known as the Norway rat or the sewer rat, the brown rat (Rattus norvegicus) is the largest species of rat in Ontario, often weighing over half a kilo and measuring around 23 cm (not including the tail). Although its colour varies from medium brown to black, Its smaller tail and larger body size distinguishes it from the black rat.


A true omnivore, brown rats will eat almost anything, which is one of the reasons why they are so invasive. Grains and cereals are their preferred dietary staple, so you can find them raiding bird feeders and dry cat or dog food left outside. In urban environments, you will also find them going inside homes and restaurants to devour stored or leftover food. They will readily chew through boxes and plastic containers to get food.

Where to find them

Although native to northern China, brown rats were introduced to other countries when international trade started flourishing during the 1700s. Today, they can be found on every continent except Antarctica. They were originally a forest species but now prefer to dwell near urban areas due to easy food access. You can find them in fields, sewers, barns, commercial buildings and unfortunately, your home.

Reproduction rate

Rats are prolific breeders, with females being able to reproduce at three or four months of age. They typically have five litters a year but can potentially produce more offspring when food is readily available. The young are hairless and blind, but their eyes open at six days old and they are eating solid food by three weeks. Average litter size is six to 11 babies, but there have been recorded instances of litter sizes reaching 22.

Common diseases

There are a number of risky diseases that brown rats can spread to humans, usually through their urine or feces. They include:

  • Salmonella
  • Listeria
  • Leptospirosis or Weil’s disease
  • Toxoplasma gondii 

Signs of an infestation

Brown rats are more active at night, so you’ll spot signs of an infestation long before you actually see a rat. If you notice any of the following in or around your home, you have a potential rat problem:

  • Scratching noises: If you hear scratching noises in your walls or behind furniture, especially at night, rats are likely the culprit. 
  • Droppings: Brown rats leave dark brown droppings shaped like grains of rice.
  • Footprints: Rats leave foot and tail marks in dustier areas of the home.
  • Rub marks: Dirt and oil from their fur often leaves smudges on wall or furniture surfaces. Rats use established travel routes, so this debris will usually be in the same area.
  • Gnawed furniture and food boxes: Rats chew up available materials such as cardboard, fabric and paper to make nests. They will also chew on food containers to access and consume the contents.

How to keep them out of your home

There are steps you can take to keep a brown rat infestation out of your home. 

  • Eliminate entry points by putting weather seals around all doors leading outside, repairing torn screens and sealing gaps around pipes. Remember that rats only need a half-inch opening to get inside your home.
  • Store all food items in the fridge or in secure containers. 
  • Cover household waste stored outside, such as compost containers and garbage awaiting collection.
  • Keep your yard and garden clean to eliminate potential nesting sites. This includes removing debris, clearing away piles of wood and cutting back overgrown areas.
  • Remove standing sources of water, like buckets. 
  • If you feed birds, use a table or feeder basket if possible to avoid attracting brown rats.

Need brown rat control services?

For minor infestations, you may be able to prevent it from growing by using traps or poison from a garden centre or hardware store. When laying them, make sure that they are not in a place that can be accessed by children or pets.

Brown rats are adaptable and breed quickly, so DIY rodent control measures may not be sufficient. If the infestation is large or the traps and poison don’t appear to be making an impact, you should contact a professional pest control company.

At Action Pest Control, we use a variety of proven methods to help you deal with your rat control problem. If you live in or around Hamilton, Burlington or Oakville, let us give you peace of mind by eliminating brown rats and the health risk that they represent to you and your family. We are available 24/7, so whenever you need professional pest control services, we’re there.

Contact us at any time to  learn more about the services we offer or schedule a home visit.