Educational Profile
Norway Rat
The Norway rat (Rattus norvegicus) is the larger commensal rodent established in Ontario urban centres. It nests in burrows, sewers, and structures, and its presence is a documented public health concern. We do not service rats. This page explains the biology, the regulatory context, and how to find competent management.
Quick facts
Identification
Norway rats are substantially larger than house mice and have a thick, blunt body with relatively small ears and a tail shorter than the body. Droppings are 12 to 19mm long, capsule-shaped with blunt ends, and concentrated near nests, runs, and feeding sites. Active burrows have entrance holes 5 to 8cm in diameter, often with a smooth pad of trampled vegetation at the entrance.
The roof rat (Rattus rattus) is occasionally documented in Ontario port cities but is not established. The Norway rat is the dominant urban rat in Toronto, Hamilton, Ottawa, and most other Ontario centres.
Where Norway rats live
Norway rats are excellent burrowers and prefer to nest in soil, often near food and water. In urban settings they exploit:
- Sewers and storm drains (population reservoir for many cities)
- Burrows under sheds, garages, garbage corrals, and decks
- Riverbanks, creek edges, and ravines
- Compost bins and bird feeding areas
- Restaurant garbage areas, alleyways, and underground parking
- Wall voids and basements of older buildings
Major Ontario cities monitor sewer rat activity through trapping and bait station programs. The Toronto Public Health Rat Response, for example, coordinates inspection and treatment of public spaces and provides guidance for property owners. Rat issues that persist despite individual property control often trace to a neighbourhood-level issue requiring municipal coordination.
Why rats are a public health issue
Norway rats are competent reservoirs and vectors of multiple human pathogens:
- Leptospirosis (urinary shedding into water sources)
- Salmonella (fecal contamination of food preparation surfaces)
- Hantavirus (less commonly than deer mice but documented)
- Rat-bite fever (rare but real)
- Plague (vector via the rat flea; not currently active in Ontario)
Beyond the pathogen list, rat populations cause documented harm through structural damage (gnawing of wires, plumbing penetrations), allergen exposure, and food spoilage. This is why municipal public health units take rat reports seriously and why most cities have a regulatory framework requiring property owners to control rat infestations on their property.
The professional approach
A reputable Norway rat management program in 2026 typically includes:
- Inspection and burrow mapping. Identifying active burrows by entrance condition, runways by grease marks and droppings, and food and water sources.
- Exclusion. Sealing all openings 12mm or larger that lead into the building. Hardware cloth (6mm), sheet metal, and concrete are appropriate; foam alone is gnawed through.
- Sanitation. Removing food sources: secured garbage in metal cans with tight-fitting lids, fixed pet feeding routines, removal of fallen fruit, and regular cleanup of garbage corral areas.
- Trapping. Snap traps and live traps in protected stations near active burrows and runways.
- Rodenticide bait stations only where appropriate, in tamper-resistant stations placed where non-target wildlife and pets cannot access them.
- Monitoring over weeks to months until activity stops.
Avoid programs that rely solely on rodenticide bait without exclusion. Bait alone reduces population temporarily but does not address the underlying conditions; new rats arrive from the surrounding area as quickly as the population is reduced.
Frequently Asked Questions
Are rats common in Ontario?
Norway rats are established in all major Ontario cities and most mid-sized urban centres. The density varies by neighbourhood; older neighbourhoods with mature sewer infrastructure, rear-laneway garbage corrals, and multiple food and water sources support higher populations than newer subdivisions.
How do I report rats?
Most Ontario municipalities accept rat reports through their 311 or public health line. Toronto, Hamilton, Ottawa, Mississauga, and most other large municipalities have web forms specifically for rat reports. Reports help municipal coordination and are often the first step in getting public-property issues addressed.
Will my city kill rats on my property?
Most Ontario municipalities provide treatment of public-property rat issues (parks, sewers, public alleyways) but do not treat private property. Private property rat control is the property owner's responsibility, and municipalities may issue work orders requiring action. Hire a licensed structural pest contractor for private property work.
Are rats dangerous?
Rats are documented zoonotic pathogen reservoirs and structural pests. The actual risk of disease transmission to a single person from rat exposure in Ontario is low but real, particularly for leptospirosis (water contact) and salmonellosis (food preparation). The structural damage and allergen exposure from established populations are more consistent issues.
Why does Spider Squad not service rats?
Rat management is structural pest work involving exclusion, trapping, monitoring, and (where appropriate) bait stations. It requires interior building access, exterior burrow inspection, and multi-visit follow-up. Our service model is exterior pest control. We refer rat calls to structural contractors with rodent experience.
Related Reading
Spider Squad - Ontario Pest Control
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