Common rock rat (Zyzomys argurus)

Common rock rat
IUCN Red List species status – Least Concern LEAST

Top facts

  • The common rock rat is a small, delicately built nocturnal rodent.
  • Female common rock rats are able to give birth to several litters each year, sometimes with as little as two months in between each one.
  • The common rock rat’s tail is thickened at the base and can be lost more easily than the tails of some other rats and mice as it is extremely delicate.
  • Populations of the common rock rat show remarkably little genetic variation despite the wide geographic range of this species. 
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Common rock rat fact file

Common rock rat description

GenusZyzomys (1)

A small nocturnal rodent (2) (4), the common rock rat (Zyzomys argurus) is endemic to Australia and is considered unusual for the lack of genetic variation between individuals across its wide range (1).

Like all rock rats, the common rock rat is of slight build (4), with yellowish-brown fur on its upperparts and cream fur on its belly (2). Its barely furred tail is distinctively thicker at the base, ends in a tuft (2), and is extremely delicate which can cause it to break readily (4) (5). The common rock rat’s hind feet are wide and have large pads that help it jump from rock to rock (2) (5). Rock rats have small, round ears, and females of this rodent group have four mammae (4)

Also known as
common Australian rock rat, common rock-rat, silver tailed rock rat, white-tailed rat.
Length: 8.5 - 10 cm (2)
Male weight: c. 33.8 g (3)
Female weight: c. 48 g (3)

Common rock rat biology

Although the common rock rat’s diet consists mainly of plants, seeds and grains, it is also known to occasionally feed on insects (2) (4).

A nocturnal species (4), the common rock rat lives solely within rocky habitats (6). This species is abundant from September, late in the dry season. However, its population numbers always fall dramatically by the end of the wet season in April (4) (7). The cause of this sharp decline is believed to be death due to stress rather than dispersal caused, among other factors, by the lack of nutritious food available during this time (7).

Common rock rats breed throughout the year but a peak is often observed in April, perhaps due to the increase in seed availability at the end of the wet season (7) (8). Sexual maturity is reached at 4 to 5 months old, and the gestation period for this species is 32 to 34 days (4). Although one to six young may be born (4) (7), litters of two or three are more common (5). Females are able to give birth to several litters each year, generally waiting 2 to 14 months between each litter (4). When the young are large enough, the female common rock rat will drag them around beneath her, attached to her teats (2), and weaning occurs after 35 days (8).

Common rock rats have particularly delicate tails from which hair and flesh will strip with ease. Once the bare skeletal section of the tail is lost, the rock rat will be left with a short stump (4). Fat is stored in the base of the tail, particularly when food is abundant (2), and its thickness is a good indicator of health in this species (7). Loss of the tail could, therefore, be detrimental to an individual common rock rat’s survival when food availability is low (9). Parasitic mites have been found to be a major cause of tail loss in this species (9)


Common rock rat range

The common rock rat is endemic to Australia (1), its range extending from northern Western Australia, through Northern Territory to northern Queensland (2) (4). It is also considered common on Barrow Island, off the coast of Western Australia (2)


Common rock rat habitat

The common rock rat is particularly well adapted to dry, rocky environments (1) (4) (5) and is found in areas where broken rock fragments are common, such as scree slopes or limestone formations. This species will also occupy buildings, dune ridges (2), open forest, woodland and scrubland (4).


Common rock rat status

The common rock rat is classified as Least Concern (LC) on the IUCN Red List (1).

IUCN Red List species status – Least Concern


Common rock rat threats

There are no recognised threats to the common rock rat at present (1)


Common rock rat conservation

No conservation measures are currently known to be in place for the common rock rat. 


Find out more

Find out more on the common rock rat:

Find out more about conservation in Australia:



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A species or taxonomic group that is only found in one particular country or geographic area.
Genetic variation
The variety of genes within a particular species, population or breed causing differences in morphology, physiology and behaviour.
The state of being pregnant; the period from conception to birth.
The organs of females that produce milk. Also known as mammary glands.
Active at night.
Small loose rock debris covering a slope.


  1. IUCN Red List (April, 2013)
  2. Moro, D. and MacAulay, I. (2010) A Guide to the Mammals of Barrow Island. Chevron Australia, Perth. Available at:
  3. Claver, M.C. (1991) Total food consumption of some native Australian small mammals in the laboratory. Australian Mammology, 14: 139-142.
  4. Nowak, R.M. (1999) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
  5. Calaby, J. and Taylor, J.M. (1983) Breeding in wild populations of the Australian rock rats, Zyzomys argurus and Z. woodwardi. Journal of Mammalogy, 64(4): 610-616.
  6. Wolff, J. and Sherman, P. (2007) Rodent Societies: An Ecological and Evolutionary Perspective. University of Chicago Press, Chicago.
  7. Bradley, A., Kemper, C., Kitchener, D., Humphreys, W., How, R. and Schmitt, L. (1988) Population ecology and physiology of the common rock rat, Zyzomys argurus (Rodentia: Muridae) in tropical northwestern Australia. Journal of Mammalogy, 69(4): 749-764.
  8. Douglass Hayssen, V., Van Tienhoven, A., Van Tienhoven, A. and Asdell, S. (1993) Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-Specific Data Biology of Disease Vectors. Comstock Pub. Associates, Ithaca.

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Common rock rat  
Common rock rat

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