R05 · Rodent
Rats & Mice
Rattus norvegicus / Mus musculus
Gnaw electrical wiring (a leading cause of house fires) and contaminate food with urine and droppings.
- Size
- Mouse 7 cm, Rat 20–25 cm body
- Habitat
- Roof voids, sub-floors, sheds, compost
- Activity
- Year-round, peak in autumn
Safety Warning
Always use lockable bait stations to protect children, pets and wildlife. Never scatter loose bait pellets.
Overview
Three species cause issues in Australian homes: the Norway rat (sewers, sub-floors), the roof rat (ceilings, trees) and the house mouse (everywhere). Rodents are neophobic — they avoid new objects — so traps and baits often take a few days to work. They breed rapidly: one pair can produce 50+ offspring a year.
How to identify
- Droppings: mouse 3–6 mm, rat 12–18 mm, usually near food sources
- Scratching or scurrying in the ceiling at night
- Gnaw marks on timber, plastic and packaging
- Greasy 'rub marks' along walls where they run repeatedly
General guidance only. Information on Home Pest Defence is provided for educational purposes and is not a substitute for professional advice. For termites, venomous spider bites, wasp nests in walls, or protected wildlife, contact a licensed pest controller, your GP, or the relevant state wildlife authority. In emergencies call 000; for poisoning call 13 11 26.