Biosecurity Spotters logo

Norway rat (Rattus norvegicus)

The Norway rat is one of the common pest rodent species in Victoria. It can damage food supplies and property, and contaminate food with excrement.

Key facts

Type: Pest animal, mammal.

Native to: Introduced to Australia.

Established in: QLD, NSW, ACT, VIC, TAS, SA, WA, NT.

Other names: common rat, sewer rat, brown rat.

Best time to act: Norway rats are usually active at night.

Identification

  • It is the larger of the two pest rats described here.
  • Its fur is brown or grey, with grey belly fur and grey feet.
  • It has a large build, blunt nose, and short, thick ears with fine hair.
  • Its head and body are 20–27 cm long, its tail is 16–20 cm long, and it weighs 200–500 grams; its droppings are banana- or sausage-shaped.
  • Look-alike: The roof rat is smaller and more slender, with a pointed nose and a tail about 25 cm long.

Where it lives

Norway rats are pest rodents in Victoria, and rodents can occur in domestic households, commercial businesses, farms, manufactures and livestock settings.

Why it matters

  • Rodents consume and destroy food sources, which can cause damage in domestic, commercial, farm and livestock settings.
  • They gnaw through many materials and can ruin food supplies by excreting on them.

How it spreads

  • Females can have 5–6 litters per year, averaging 8–10 pups per litter.
  • The gestation period is 21 days, and young reach sexual maturity at 3–4 months.

Control methods

  • Reduce food, water and shelter sources by maintaining good hygiene and removing clutter, food scraps, nesting sites and shelters.
  • Trapping can be used where chemical pesticides are not accepted, such as food premises, or to capture individual rodents that are not taking bait.
  • Pest control operators usually use rodenticides; follow the product label, use appropriate protective equipment, and keep baits inaccessible to children, pets, wildlife and livestock, or use lockable bait stations.
  • In Victoria, the sale and use of glue traps for trapping animals, including for rodent management, is prohibited.

Site hygiene and welfare

  • Maintain good hygiene and remove food scraps and other possible food sources around the site.
  • Do not place baits or tracking powder where they could contaminate food or food-handling areas.
  • Use methods set out in the national model codes of practice and standard operating procedures for the species.
  • Coordinate control with neighbours and the local government biosecurity plan, as isolated effort is quickly undone by reinvasion.

Classification by state

  • Australia (national): Key threatening process. Listed under the EPBC Act, with a national threat abatement plan for exotic rodents on offshore islands.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: General biosecurity duty. Not prohibited matter in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Declared animal. Declared animals have legal restrictions, which can cover keeping, moving, selling and releasing them, and landowners may be required to control them.
  • Western Australia: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • Tasmania: Not a declared pest. Not a declared pest or prohibited matter in Tasmania. Importing animals is still controlled by Biosecurity Tasmania.
  • Northern Territory: Not a declared pest. Not on an NT declared or prohibited list. Check with the NT Government before keeping, moving or releasing it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources