Rodent identification advice from Sydney’s pest control team

Rats and mice can be a serious and very damaging problem to food production, warehouse, office and all types of commercial facilities. The main types of pest rodent which are encountered in commercial/industrial businesses are listed below.

Roof rats can be a major problem particularly in larger, built up areas. They are omnivorous and feed on a range of stored food products, grains, cereals etc. however they are known to prefer vegetable and fruit matter. The roof rat does not tend to burrow, but is a skilled climber, making it able to nest in the high up roof cavities, wall cavities and the upper parts of tall warehouses and other buildings. They are also often a problem on ships and in buildings around sea ports.

• Usually between 16-25cm in length and can weigh up to 200g
• Range from Black to brown to grey in colour
• Have a more slender body than the Norway rat, with a more pointed type of nose and large ears
• Tail is longer than the head and body
• Females have around 6-8 young per litter, and can have up to 5 litter’s per year in usual circumstances
• Droppings are approx. 12mm in length with pointed ends

Norway rats are the largest of the two main pest rats in Australia, it is more widespread and probably causes the most damage of any pest rodent to commercial/industrial premises. They are omnivorous and feed on a large range of stored food and food waste including meat, fish, cereal products, grain and many others. They infest all nature of commercial buildings as well as sewers. Habitually, the Norway Rat also lives in burrows in outdoor areas and may enter buildings to feed and then return to their outdoor burrows.

• Usually between 20-40cm in length and can weigh up to 450-500g
• Brown to red-brown in colour
• Have a more heavy-set, thick body than the Roof Rat, with a blunt nose and small ears
• Tail is shorter than the head and body
• Females have around 8-10 young per litter, and can have up to 6 litters per year in usual circumstances
• Droppings are approx. 18mm in length with rounded ends

The house mouse is a smaller rodent then the pest rats, making many more areas accessible for nesting to it. They are omnivorous and eat a variety of foods, seeming to prefer dry cereal products if available along with water. They are a pest in many commercial food production/processing facilities and may live either indoors or outdoors around buildings, entering to feed or when conditions are poor outside.

• Usually between 7-10cm in length and can weigh up to 20g
• Range from brown to grey in colour
• Has a generally slender body, with a pointed nose and large ears
• Have smaller head and large eyes when compared to juvenile Norway Rat, also have smaller feet
• Tail is approx. same length as head and body
• Females have around 5-6 young per litter, and can have up to 10 litters per year in usual circumstances
• Droppings are approx. 4mm in length with pointed ends