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Common Australian Rock Rat

Zyzomys argurus

French: Zyzomys a queue d'argent / German: GemeineDickschwanzratte / Spanish: Rata de roca de Australia

Other common names: Common Rock Rat, Silvertailed Rock Rat

Taxonomy. Mus argurus Thomas, 1889,

“South Australia.” Clarified by D. J. Kitchener in 1989 as “Northern Territory,” Australia.

Placed in Zyzomys by H.A. Longman in 1916, Z. argurus has been kept in that genus by all subsequent authors. Monotypic.

Distribution. Widespread but fragmented range across mainland N Australia, from the Pilbara E to SE Queensland, and many islands off N Australian mainland.

Descriptive notes. Head—body 85-122 mm, tail 90-130 mm, ear 16-20 mm, hindfoot 20-26 mm; weight 26-60 g. The Common Australian Rock Rat is golden brown to gray brown above, white below; it has large prominent eyes, long vibrissae, and a tail that is often markedly thickened (with stored fat) at base. Part or all of the tail is often missing (presumably a response to attempted predation). Distinguished readily from other co-occurring Zyzomys species by its smaller size and absence of long hairs at tail tip.

Habitat. Largely restricted to rocky areas, with a broad range of vegetation types including heathlands, hummock grasslands, eucalypt woodlands and monsoon rainforests.

Food and Feeding. Diet includes a range of seeds, fruits, and other vegetable matter, with seasonal variation in dietary composition relating to phenological patterning in tree, shrub, and grass species. This murid also eats some invertebrates and fungi, but these are generally minor components of diet.

Breeding. Common Australian Rock Rats breed year-round, but with peak in early dry season (March—May); they may reproduce several times per year. Gestation lasts ¢.35 days; litter size is 1-6.

Activity patterns. The Common Australian Rock Rat is terrestrial and nocturnal, sheltering during day in cracks and crevices among boulders and scree.

Movements, Home range and Social organization. Common Australian Rock Rats are generally sedentary. In a Kimberley study, densities reported as varying from 2-3 ind/ ha to 12-8 ind/ha, with individual home ranges ofc.0-1 ha. Abundance may decline locally at end of wet season (April). In contrast to many co-occurring small-mammal species in northern Australia, this rock rat’s populations have mostly been stable over recent decades.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Not listed as threatened under Australian legislation.

Bibliography. Abbott & Burbidge (1995), Begg (1981), Begg & Dunlop (1985), Bradley et al. (1988), Cole & Woinarski (2002), Gibson & McKenzie (2012), Jackson & Groves (2015), Kitchener (1989), Longman (1916), McKenzie et al. (1978), Van Dyck & Strahan (2008), Watts (1977), Watts & Aslin (1981), Woinarski, Armstrong et al. (2010), Woinarski, Legge et al. (2011), Woinarski, Palmer et al. (1999), Woinarski, Ward et al. (2011).