Roof rats (Rattus rattus) are highly adaptable, nocturnal rodents who transmit diseases, and have helped cause devastating plagues around the world in past and present times. Their adaptability has been key in their ability to survive and thrive.

Roof rats have smooth and sleek black or brown fur, large ears, large eyes, and a pointy nose. They can grow to over 40 cm long. Roof rats have long, hairless, scaly tails, which are often longer than the combined length of their head and body. Compared to a Norway rat, a roof rat’s body is more glossier and smaller. Like all rodents, their teeth continually grow, and therefore they gnaw to help keep them a manageable size.

   A Roof Rat outside a home

These rodents can squeeze through holes as small as a quarter. This is because they have small bones and are extremely flexible. If a roof rat can fit its head through a hole, it can collapse its body and pull itself through. They are fast, and amazing climbers, frequently nesting in high places like trees, attics, rafters and roofs (hence their name ‘roof rat). They even nest on the ground if needed. If you come across a live roof rat in your home or business during the day, this is likely a sign that there are more. Live sightings during the day typically occur when current nests are full, or have recently been disturbed.

Roof rats are omnivorous, and will eat just about anything. They are also huge hoarders of food. While they favour fruits, they will dine on grain, meat, seeds and even bark.

Roof rats reach sexual maturity between 2-5 months, and are incredible breeders. In crowded roof rat populations, a social hierarchy will be formed, whereby the most dominant males will mate more often with female rates. A female roof rat can breed year-round, and in a single year can birth as many as 40 new rats. Rodent litters average 6 to 8 rats in size. Roof rat’s life span is often 1 year.

Rats pose a serious safety hazard due their constant chewing. They will gnaw through just about everything, including electrical wires. They can cause electrical shortages, and even electrical fires.  They also cause damage by tearing up insulation in walls and attics through burrowing and nesting.

In addition to causing food poison to humans through contaminating food or the surfaces food is prepared on, roof rats can carry and transmit diseases like Rat-Bite Fever (RBF) and Trichinosis, through biting, physical contact and contamination. Fleas that feed on dead rodents, can also pass along these diseases to humans. So, whether alive or dead, roof rats pose serious a serious health concern.

Here are some signs that you have a roof rat infestation:

  • Seeing alive or dead rodents.
  • Finding nests (empty or occupied).
  • Discovering roof rat droppings, which appear pointed at both end and are around 12mm in length.


To help prevent roof rats from inhabiting your home or business or to help get rid of rats, it is crucial to remove their food source. Here are some helpful tips:

  • Seal up cracks and crevices around your windows, doors, eaves, chimney, and any other entry point
  • Replace broken screens over windows and vents, or install new ones.
  • Install, repair or replace damaged weather stripping.
  • Trim back bushes and tree branches so they are away from your home or business is also helpful, as roof rats are exceptional climbers, and can use these to gain access to your roof.
  • Use indoor garbage cans with secure lids, and empty regularly.
  • Store outdoors away from homes and buildings, and secure with tight-fitting lids.
  • Store dry foods in tightly sealed containers.
  • Regularly clean and sanitize your kitchen, and other eating areas.

Learn more about getting rid of roof rats.

If you uncover a roof rat infestation contact a licensed pest professional, like Environmental Pest Control with rat control experience.

Call 1 (800) 263-5055

Our Professional Team is Happy to Help!