Black rat, ship rat, house rat
Found worldwide, adapts well to most climatic conditions. In Australia, it is the most commonly encountered rat species.
The roof rat is a natural climber, so will commonly be found nesting in an elevated position. Roof spaces and tree tops are common nesting sites. However it is also comfortable nesting on the ground and roof rat burrows are very common, often located under slab edges and flooring.
The roof rat is a prolific breeder and a female can have 5-10 young in a litter and up to 6 litters per year. They are happy to inter-breed within families. Social groups are often formed of multiple males and multiple females. One male tends to be dominant. Two to three females are often dominant to all other group members except the dominant male. Lifespan in the wild is 12 to 18 months.
Colour: Variable – Black to light grey-brown with a lighter underside
Size range (adult): Body 15-20 cm, Tail 18-25 cm, Weight: up to 350 g
The major distinguishing feature of the roof rat is the length of its tail – which is longer than the body. It has large ears and large feet. Both the tail and the feet help with climbing.
Roof rats are omnivorous and will eat a wide range of foods, including seeds, fruit, stems, leaves, fungi, and a variety of invertebrates and vertebrates. An adult will eat 15-30 g of food in a day.
Roof rats will spread disease in various ways. Their urine and faeces will transport infections and their fur is recognised as being a carrier of several bacteria. Diseases of note include Leptospirosis, Salmonella, Hantavirus and others.