Plains rat
Common name: plains rat
Scientific name: Pseudomys australis
Family: Muridae
Conservation status: The plains rat is Endangered in Queensland (Nature Conservation Act 1992) and Vulnerable nationally (Environment Protection and Biodiversity Conservation Act 1999). It is considered a data deficient species under the Department of Environment and Resource Management Back on Track species prioritisation framework.
Description
The plains rat has a body length of between 10 cm and 14 cm and weighs between 30 g and 50 g. It is grey to grey-brown above and white or cream below with relatively large ears. The tail is equal to, or shorter than, the head and body length.
Habitat and distribution
Populations of the plains rat were once found from the western edge of the Nullarbor Plain to the inland slopes of the Great Dividing Range, central Queensland and at the mouth of the Murray River. The plains rat is now restricted to the gibber plains of the Lake Eyre basin. No specimens of the plain rat have been collected in Queensland since 1936, although remains of this species have been recently found in owl droppings.
Two habitat types are critical for the species survival: gibber plains (flat desert covered with boulders and small stones) with cracking clay depressions supporting perennial open shrubland and large areas of open cracking gypsum-clay soil associated with minor drainage features.
Life history and behaviour
This species forages and is active during the cool of night. The plains rat constructs shallow, complex burrow systems that are dug into the gibber or the softer soil around the bases of shrubs. It is likely that the rat predominantly eats seeds, supplemented with vegetable matter and insects. It is able to survive without drinking, as water is obtained from the metabolism of starches in its food.
A social rodent, the plains rat lives in small colonies, but following good rain populations have been known to become very abundant. Little is known about the plains rat's breeding but it is thought that breeding only occurs following heavy rain, when the availability of resources increase. Gestation lasts up to 31 days and litter size is usually three to four, but can be up to seven. Young are ready to leave the nest 28 days after birth.
Threatening processes
The decline in this species is probably due to the impacts of introduced stock and rabbits on vegetation. Introduced predators such as red foxes, feral cats and dingoes may also take a number of these rodents. Native predators include letter-winged kites, barn owls, mulga snakes and other large snakes.
Recovery actions
- Undertake surveys and population studies to determine species distribution, habitat requirements, reproductive biology, social organisation and potential threats and limiting factors.
- Enough habitat should be protected to maintain or increase the current distribution. Therefore additional conservation reserves may be required.
- Management of domestic stock is required as these can seriously disrupt the rat's habitat.
Related information
Watts, C.H. (1995) 'Plains rat' in The Mammals of Australia (ed. R. Strahan) Australian Museum and Reed New Holland, Sydney.
Last updated 4 February 2011