Threats/Control Methods - Regional
The Black Rat can be a threat to human health. This species has been identified as a potential carrier of diseases that can affect humans, such as Hantaan virus (Haemorrhagic fever), Murine typhus (Rickettsia typhus), Leptospirosis, Rat bite fever (Spirillium minor) and the Plague (Yersinia pestis). The potential health impacts of this species are currently being researched at the CSIRO.
Threats/Control Methods - Local
These Rats can be difficult to control because if the mother rat has become wary of chemical deterrents like 'Ratsac' or traps, many of her young will also learn to avoid them.
There are some indicators that give clues to whether a Black Rat is inhabiting a residency. Look out for grease smears on vertical surfaces, evidence of gnawing, smell, strange noises at night, disappearing food and strange reactions from your own pets. Rats are difficult to remove from an area relying on common traps and baiting methods alone, and usually trained pest controllers are the most effective.
Black Rat, Roof Rat
Body size is about 8cm in length. The upper body colouring is brown, black or charcoal grey, with a cream or white underbelly. The tail is scaly and long relative to its body size. Front teeth are chisel shaped.
This species is found widely across Australia, especially in the coastal regions in human modified areas. It is also found commonly in and around human settlements where food and shelter is readily available in most countries of the world.
Country of Origin
Conservation (Pet/Pest) Status - National
Conservation (Pet/Pest) Status - Regional
Associated vegetation community
In their natural environment Black Rats are common to woodlands, forests and grasslands. They are typically associated with human settlements, including cities, rural villages and farms.
Black Rats are very adaptable and can live in a variety of places such as roofs, cavity walls, trees, scrapes or burrows around farms. A close distance to humans usually ensures the food and water requirements of this species are met.
A mature female rat can give birth to about 20 young in a year (4 to 6 at a time). Young are born in nests made from paper, rubbish, plastics, grass or other material. They become completely independent and able to reproduce after three months. Outdoor populations in the natural environment tend to peak in summer or early autumn, while indoor populations remain constant throughout the year.
Black Rats are very good swimmers and climbers, meaning they can access most areas to feed, shelter and breed. Usually they move about 50m from their nest site. They will climb trees to steal eggs out of birds' nests or to eat fruit. They are known to cause trouble by gnawing at pipes and electrical cords. Rats have very poor vision, relying on their keen sense of smell, acute hearing and their whiskers and sense of touch. They spend time around water bodies and beaches and are the most commonly seen rodent in public parks and beaches.
In the wild, Black Rats will eat a range of fresh plant material, nuts and seeds, fruit and vegetables and tree bark. In human environments they are known to eat almost anything.
Feral or domestic Cats (Felis catus ) and Dogs (Canis familiaris), snakes, birds of prey, and other rats will all attack and kill Black Rats
If the mother rat has become wary of rodenticides or traps, many of her young will learn to avoid them. This learning experience can make management difficult in sites where long-term rodent suppression programs have been unsuccessful in the past.
References - (reader suitability of references, P=Primary teachers, S=Secondary students, T=Tertiary students and researchers)
CSIRO Sustainable Ecosystems. 2005. Research Projects and Activities: Rats in Urban Areas. CSIRO Australia. [online]. Available at: http://www.cse.csiro.au/research/rodents/research.htm#australia6 S, T
Tidemann, C., Roscoe, T. and Mitchell, B. 2006. Mammals of the Lower Sullivans Creek Catchment, Canberra ACT. Prepared for the Life in the Suburbs project using data from the Lower Sullivans Creek Catchment Ecological Survey (LSCCES). Australian National University. Canberra. [online]. Available at: http://www.lifeinthesuburbs.com.au/category.php?id=65 S, T
Rockdale City Council. Unwanted Visitors. Produced as part of the Council's Rodent Control Program. Rockdale NSW.http://www.rockdale.nsw.gov.au/pdf/a_rat_brochure.pdf P, S, T
Watts, C. and Kemper, C. Fauna of Australia. 47. Muridae. Department of Environment and Heritage. [online]. Available at: http://www.deh.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/47-ind.pdf P, S, T
Researcher: Hedda Ranson-Elliott and Naomi Hogan