Identification
The Norway rat is common in urban areas. It nests in burrows, under debris or in basements, crawl spaces and suspended ceilings.
HEALTH RISKS
Rats can transmit diseases through their urine, droppings, fleas and bites. Avoid touching droppings and nests without gloves; dampen them with a disinfectant rather than sweeping or vacuuming them.
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ABlunt snout
Blunt snout, small eyes and small ears, large feet.
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BScaly tail
Scaly, nearly hairless tail, shorter than the body (unlike the roof rat).
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CPowerful incisors
Incisors that grow continuously and that the rat wears down by gnawing.
Adult
Gnaws to wear down its incisors and to reach food. Digs complex burrows with nesting and storage chambers.
Juvenile
Smaller than adults, with a proportionally large head and feet. A young rat can be mistaken for a mouse.
Life cycle
VIVIPAROUS · 2 TO 14 YOUNG · 3 TO 6 LITTERS PER YEAR2 to 14 young per litter (about 7 to 8 on average). Gestation of 21 to 25 days, weaning at 3 to 4 weeks.
After weaning, the young rat becomes independent and looks for its own food.
Sexual maturity at about 3 to 5 months. A female can have 3 to 6 litters per year.
KEY DIFFERENCES
The rat is often confused with the mouse or other rodents
House mouse
Smaller (body about 5 to 10 cm), droppings about 3 to 6 mm, thinner tail.
Roof rat
Body 15 to 20 cm, tail longer than the body, large eyes and large ears.
Signs of activity
Typical droppings
Droppings 1.3 to 1.9 cm long with blunt ends, along walls and runways.
Gnaw marks
Gnaw marks on cables, doors, wall corners and pipes.
Burrows and greasy runways
Burrows along foundations or under debris, and greasy marks where the fur rubs against walls.
Rats often use the same runways along walls.
Treatment
INTEGRATED PEST MANAGEMENT
- 1 Snap traps Placed on active runways, first baited without being set to get the rats used to them
- 1 Rodenticide in a secure bait station Rodenticide baits in locked, tamper-resistant stations, out of reach of children and pets
- Phase 1: bait the traps without setting them for a few days, until the bait has been taken several times, to get around the rats' wariness (neophobia). Use baits such as peanut butter, nuts or bacon.
- Phase 2: set the traps or place the secure rodenticide stations. Check the traps often. Seal entry points at the same time to keep other rats from coming in from outside.
Rats are wary of new objects and may avoid traps and baits for several days. Leaving traps baited but unset until the bait has been taken helps keep them from becoming trap-shy.
Always place rodenticides in locked, tamper-resistant stations. Rodenticides pose risks to children, pets and wildlife, including through secondary poisoning.
Store all food in airtight containers, secure garbage bins and eliminate sources of standing water. The less food and shelter there is, the less the property attracts rats.
ASSESSING THE INFESTATION
Determine the extent before treatment
Identify greasy runways, burrows and gnawed areas to map the rats' movements
Rats are mostly active at night: noises and comings and goings at night help locate active runways
Inspect the foundations, sewer lines and pipe penetrations to identify entry points into the building
Prevention
- Seal the foundations
Seal every opening larger than 6 mm in the foundations with a material rats cannot gnaw through, such as steel wool, metal mesh or sheet metal. Rats gnaw through wood, plastic and foam.
Foundation - Secure the garbage
Sturdy garbage bins with tight-fitting lids. Compost in a closed composter. Pick up outdoor food spills right away.
Outdoors - Remove harbourage
Clear woodpiles, rubble and cluttered materials away from the foundations. Cut back low branches of trees and shrubs that touch the building.
Garden - Protect the pipes
Seal around pipes and wires that go through walls and screen the vents. Rats can enter through broken drains or by coming up through the sewers.
Infrastructure
Frequently asked questions
How can I tell if I have rats?
Dark droppings 1.3 to 1.9 cm long with blunt ends, gnaw marks, greasy marks along walls, burrows near the foundations and noises at night.
Are rats dangerous?
Yes: they contaminate food, transmit pathogens and gnaw through wood, pipes and electrical wiring, creating a fire risk.
How do they get in?
Through openings as small as 1.3 to 2 cm: under doors, around pipes, through drains and foundation cracks. They climb and swim, sometimes coming up through the plumbing.
How do I get rid of them?
Seal entry points, remove food and shelter, then combine trapping with secure bait stations. An exterminator can take care of the removal and follow-up. For a solution suited to your situation, you can check out our rat extermination service.