Plains Rat - profile

Indicative distribution


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Key:
known
predicted
The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.
Scientific name: Pseudomys australis
Conservation status in NSW: Presumed Extinct
Commonwealth status: Vulnerable
Profile last updated: 07 Sep 2017

Description

The Plains Rat (Pseudomys australis) is one of the largest rodents still present in the arid zone, with a body mass up to 50 g. It has a stocky build, rounded snout and long ears. It has greyish upperparts, often lustrous in appearance, with paler flanks and cream or white underparts. The tail is also bicoloured- being brown or grey above and white underneath, and can grow to 12 cm in length.

Distribution

The Plains Rat is restricted to the gibber (stone-covered) plains of Lake Eyre Basin in northern South Australia, and is now presumed to be extinct in Queensland and NSW. The previous distribution of this species extended from the western edge of the Nullabor Range, to central Queensland, as well as the inland slopes of the Great Dividing Range to the mouth of the Murray RiverIn the Northern Territory, it was formerly present only in the extreme south-east region.

Habitat and ecology

  • The Plains Rat is primarily found in gibber (stone-covered) plains and mid slopes with boulders, small stones and gilgais (water soaks, depressions). In years of very good rainfall, this species occur on adjoining sandy plains. During poor conditions, core refuge areas may occur on low-lying gilgais and watercourses of gibbber plains.
  • During poor rainfall years, Plains Rat populations are able to survive without drinking, as water is obtained from the metabolism of starches in its food. However drainage depressions and areas of cracking clays are a sometimes a source of water and generally hold a greater concentration of seeds and dry plant matter than most other habitats. The cracks in the soil trap wind-blown material and decrease its likelihood of harvest by other species such as parrots and other birds. It has been suggested that these areas are the most productive areas of stony desert landscapes compared to sodic and unstable sections of gibber that restrict plant growth.
  • The Plains Rat forages and is most active during the cool night. A major component of the species' diet is seeds along with other plant material, while invertebrates and fungi are a minor component.
  • The Plains Rat constructs shallow, complex burrows. In this species' primary habitat, burrows/nests are dug into cracks in the gibber. In secondary habitat areas, complex burrow systems are dug in the softer, more friable soils usually found around the base of chenopod shrubs.
  • Nests are maintained by breeding females. Breeding is not seasonal but appears to be associated with increased availability of food following significant rainfall events. After these conditions deteriorate, populations can collapse and become undetectable as food resources diminish. Litter size is usually three to four (and up to seven) and weaning takes place 28 days after birth.


Threats

Recovery strategies

Activities to assist this species

IBRA Bioregion IBRA Subregion Known or predicted Geographic restrictions region