With the exception of Antarctica, rodents have successfully populated every continent in the world. There are over 2200 rodent species with over 60 native and 3 introduced pest species in Australia.

During feeding, rodents consume and destroy their food source. Rodents cause widespread damage, with devastating effects to domestic households, farms, businesses, livestock etc. These animals have adapted to living with humans and are responsible for disease and large losses of food supplies.

Rodents cause damage by gnawing and chewing on walls and electrical wiring, contaminating food supplies and spreading germs and bacteria causing illness and diseases.

While there are a large number of different species, the three that are of concern in urban areas, are the Norway Rat, the Roof Rat and the common House Mouse.


Norway Rat (Rattus norvegicus)

Also known as the common sewer or brown rat, is the larger of the pest rats having a life span of approximately 9-12 months. Female rats can have 5-6 litters per year and average 8-10 babies per litter. The gestation period is 21 days with the young reaching maturity at 3-4 months.

Norway rats are good swimmers, are nocturnal and are omnivores eating almost anything. They prefer foods rich in protein and starch but will eat meat, fish, vegetables, weeds, earthworms, nuts, fruit and crustaceans.

They grow to a length between 20-27cms (excluding the tail which can grow between 16-20cms) and weigh up to 500gms. They have a blunt nose and short ears.

Roof Rat (Rattus rattus)

Also known as the ship or black rat and have a life span usually between 9-12 months. Females can have 4-5 litters per year with each litter averaging 6-8 babies. The gestation period is 21 days with the young reaching maturity at 3-4 months.

Roof rats like to live in built up or coastal areas. They are omnivores and will generally feed on grains, fruits, cereals, meats and insects.

They grow to a length of 14-20cms (excluding the tail which can grow up to 25cms) and weigh up to 300gms. They have pointed noses, large thin translucent ears and pink feet.

Common house mouse (Mus domesticus)

The common house mouse has a life span of approximately 12 months. Females can have 6-10 litters per year. The gestation period is 21 days with the young reaching maturity at about 6 weeks.

House mice can live happily inside or outside and have adapted very well to living with humans. They eat a varied diet of fruits, nuts, grains and cereals.

Brown or grey in colour, they grow to a length of 8-10cms (excluding the tail which can grow up to 10cms) and weigh up to 20gms. They are slender with pointed noses, large hairy ears and pink feet.

Did you know?

• A rat can tread water for 3 days and survive being flushed down the toilet – it can return to the building via the same route

• Rats do not sweat. They regulate their temperature by constricting or expanding blood vessels in their tails.

• Innie or outie? Rats don’t have gallbladders or tonsils, but they do have belly buttons