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Rats and Mice

Rats and mice are well adapted to living in close association with humans. Their presence is undesirable due to their ability to physically damage structures, spoil and contaminate food and transmit diseases to humans.

They may live and nest within buildings indefinitely, provided they have access to food and water. Being creatures of habit, they will travel the same routes to the food sources therefore assisting us in the most appropriate location to place baits.

The following describes the characteristics between rats and mice and how to treat your property if you are experiencing an infestation.

Characteristics of Rats

Black Roof Rat (Photo by Peter Robertson)

There are two common types of rats in Australia, the Norway and Roof Rat. Some of the characteristics of each are as follows:

Rattus Rattus

Also known as the Black Rat, Roof Rat, Tree Rat, Ship Rat or European Black Rat.

  • Large ears and eyes.
  • Pointed nose.
  • Heavy set body.
  • Tail longer that its body.
Norway Brown Rat (Photo by Angela Frost)

Rattus Norvegicus

Also known as the Brown Rat, Norway Rat, Sewer Rat, Laboratory Rat or White Rat.

  • Small ears and eyes.
  • Blunt nose.
  • Heavy set body.
  • Tail shorter than its body.

Characteristics of Mice

House mouse (Copyright Parks Victoria)

Mus musculus

Also known as the House Mouse

  • One pair of distinctive chisel shaped incisors with hard yellow enamel on front surfaces.
  • Bulging eyes in a small head.
  • Large rounded ears.
  • Brownish-grey above, white to grey or pale yellow below; soft dense fur to 7mm long.
  • Scaly tail, about same length as body 75-100 mm.
  • 60-100 mm in size.

How to Identify Rodent Activity

Rats and mice are most active during night time. The following signs may indicate rodent activity:

  • Droppings - found near shelters/nests, feeding areas, travel paths.
  • Travel Paths - greasy markings found on surfaces in continual contact with dirty rodent fur.
  • Burrows - found outside, along walls, under buildings, in creek banks, roof insulation, and in stacked materials.
  • Gnawing - rodents gnaw a wide variety of material including woodwork, electrical cables and food containers.
  • Noise - scratching, fighting, squeaking, clawing and gnawing often heard during the night time.

Noises of running in the roof usually indicate possum activity rather than rodents.

How to Deal with Rats and Mice on Private Property

Baiting is the most effective way of dealing with rats and mice. A number of brands of baits exist and can be purchased through hardware stores and supermarkets. People with young children and pets should be especially careful and be sure to read the product instructions. Alternatively you can contact a licensed Pest Controller through the Yellow Pages or the local paper.

An information sheet on rodents including control methods can be downloaded below.

Rats and Mice on Council Property

Rats and mice located on Council property should be reported to Council’s Parks Services on 9298 8000.

More Information

Visit Museum Victoria for more information on the different types of introduced rodents into Australia, their habitat and an identification service if you have an infestation and are unsure as to what type of rodent it is.

For more information about the baiting process you can contact Knox Council's Health Services on 9298 8000 or email

1. Image of Black Roof Rat courtesy of Peter Robertson.
2. Image of Brown (Norway) Rat courtesy of Angela Frost.
3. Image of House Mouse (c) Copyright Parks Victoria.

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