BRUSH-TAILED RABBIT-RAT BRUSH-TAILED TREE-RAT ...

THREATENED SPECIES OF THE NORTHERN TERRITORY 

BRUSH-TAILED RABBIT-RAT 

BRUSH-TAILED TREE-RAT 

Conilurus penicillatus 

Conservation status 

Australia: Not listed. 

Northern Territory: Vulnerable. 

Description 

The brush-tailed rabbit-rat is a 

moderately large (about 150 g) partly 

arboreal rat, with long brush-tipped tail 

(with the distal third either black or 

white), and long ears. The fur colour 

is relatively uniformly coloured brown 

above, and cream below. It is 

distinctly smaller than the two other 

long-tailed tree-rats in the Northern 

Territory. 

Brush-tailed rabbit-rat (Photo: K Brennan) 

Distribution 

In the Northern Territory, this species 

has been recorded from near-coastal 

areas from near the mouth of the 

Victoria River in the west to the Pellew 

Islands in the east, and including 

Bathurst, Melville, Inglis and Centre 

Islands and Groote Eylandt (Parker 

1973; Kemper and Schmitt 1992; 

Woinarski 2000). There are no recent 

records from much of this historically 

recorded range, and it is currently 

known to persist in the Northern 

Territory only on Cobourg Peninsula, 

Bathurst, Melville, and Inglis Islands, 

Groote Eylandt, and a small area 

within Kakadu National Park. 

Two weakly-defined subspecies are 

recognised from the Northern 

Territory: C. p. melibius from the Tiwi 

Islands, and C. p. penicillatus from all 

other Australian areas (Kemper and 

Schmitt 1992). 

Beyond the Northern Territory, the 

species also occurs from higher 

rainfall, near-coastal areas of the north 

Kimberley, Bentinck Island 

(Queensland) and a small area of 

southern New Guinea. 

Conservation reserves where 

reported: 

Garig Gunak Barlu National Park, 

Kakadu National Park. 

Known locations of the brush-tailed rabbitrat. 

ο = pre 1970; • = post 1970.

Ecology 

The preferred habitat of the brushtailed 

tree-rat is eucalypt tall open 

forest (Firth et al. 2006a) . However, at 

least on Cobourg Peninsula, it also 

occurs on coastal grasslands (with 

scattered large Casuarina equisetifolia 

trees, beaches, and stunted eucalypt 

woodlands on stony slopes (Frith and 

Calaby 1974; PWCNT 2001). 

It shelters in tree hollows, hollow logs 

and, less frequently, in the crowns of 

pandanus or sand-palms (Firth et al. 

2006b). Most foraging is on the 

ground, but it is also partly arboreal. 

The diet comprises mainly seeds 

(especially of grasses), with some 

fruits, invertebrates and leaves and 

grass (Firth et al. 2005). 

Conservation assessment 

Conservation assessment is 

hampered by lack of knowledge 

concerning the timing, extent and 

currency of geographic decline, and 

the lack of a comprehensive recent 

assessment of their status on Groote 

Eylandt and Centre Island. Relatively 

brief recent (2003-2005) surveys failed 

to re-locate the species on Centre 

Island (Taylor et al. 2004; S. Ward 

pers. comm.), but reported one 

individual on Groote Eylandt (D. Milne 

pers. comm.). Its range and 

population size in the Northern 

Territory has probably declined by well 

over 50% since European settlement, 

but this decline cannot be dated with 

any assurance. Certainly, its current 

status no longer matches that reported 

more than 100 years ago: “in Arnhem 

Land is everywhere common in the 

vicinity of water” (Dahl 1897), 

“numerous all over Arnhem Land, and 

in great numbers on the rivers of the 

lowlands” (Collett 1897). There is 

some suggestion of a decline within 

the last 20 years at Kakadu National 

Park, but this is based on very few 

records (Woinarski et al. 2001). 

Current research will provide some 

assessment of the population size (or 

Threatened Species Information Sheet 

at least an index of abundance, whose 

assessment can be consistently 

repeated) on Bathurst and Melville 

Islands, Cobourg Peninsula and 

Kakadu. A recent study (PWCNT 

2001) found very high population 

density (>6 individuals/ha) in at least 

two locations on Cobourg Peninsula. 

Its status best fits Vulnerable (under 

the criteria B1ab(i,ii,iii,iv,v) based on: 

• extent of occurrence estimated to 

be

may have changed the availability of 

preferred or vital food resources (e.g. 

seeds or stems from particular grass 

species), and more frequent hot fires 

may have reduced the availability of 

hollow logs, tree hollows and the tall 

fruit-bearing understorey shrubs, and 

unfavourably changed the composition 

of grass species (Woinarski et al. 

2004; Firth et al. 2005, 2006b). 

The population on the Tiwi Islands has 

been substantially reduced by recent 

clearing for forestry plantation of about 

30,000 ha of its prime habitat (Firth et 

al. 2006a); and there are proposals to 

extend this forestry enterprise up to 

100,000 ha. 

Conservation objectives and 

management 

There is no existing recovery plan or 

management program for this species. 

In the interim, management priorities 

are to: 

(i) maintain a monitoring program in at 

least two sites, which can also 

measure responses to management 

actions. The baseline for this 

monitoring has now been established, 

with recent studies on Cobourg 

Peninsula, the Tiwi Islands and in 

Kakadu National Park. 

(ii) work with Aboriginal landowners to 

maintain effective quarantine actions 

for island populations, most 

particularly relating to maintaining at 

least some of these islands cat-free. 

(iii) develop effective captive 

population breeding programs, and 

evaluate the possibility of establishing 

translocated populations (either to 

currently uninhabited islands or to 

appropriately managed conservation 

reserves). Such a program is currently 

being undertaken through the Territory 

Wildlife Park. 

(iv) ensure that habitat clearance for 

plantation forestry on the Tiwi Islands 

does not compromise population 

viability. 

Threatened Species Information Sheet 

Compiled by 

John Woinarski 

[January 2007] 

References 

Collett, R. (1897). On a collection of 

mammals from North and North-west 

Australia. Proceedings of the 

Zoological Society of London 1897, 

317-336. 

Dahl, K. (1897). Biological notes on 

north-Australian mammalia. 

Zoologist, Series 4, 1, 189-216. 

Firth, R.S.C., Jefferys, E., Woinarski, 

J.C.Z., and Noske, R.A. (2005). The 

diet of the brush-tailed rabbit-rat 

Conilurus penicillatus from the 

monsoonal tropics of the Northern 

Territory, Australia. Wildlife Research 

32, 517-524. 

Firth, R.S.C., Woinarski, J.C.Z., Brennan, 

K.G., and Hempel, C. (2006a). 

Environmental relationships of the 

brush-tailed rabbit-rat Conilurus 

penicillatus and other small mammals 

on the Tiwi Islands, northern 

Australia. Journal of Biogeography 

33, 1820-1837. 

Firth, R.S.C., Woinarski, J.C.Z., and 

Noske, R.A. (2006b). Home range 

and den characteristics of the brushtailed 

rabbit-rat Conilurus penicillatus 

in the monsoonal tropics of the 

Northern Territory, Australia. Wildlife 

Research 33, 397-408. 

Frith, H.J., and Calaby, J.H. (1974). 

Fauna survey of the Port Essington 

district, Cobourg Peninsula, Northern 

Territory of Australia. Technical 

Paper no. 28. (CSIRO Wildlife 

Research, Canberra.) 

Kemper, C.M., and Schmitt, L.H. (1992). 

Morphological variation between 

populations of the brush-tailed treerat 

(Conilurus penicillatus) in northern 

Australia and New Guinea. 

Australian Journal of Zoology 40, 

437-452. 

Parker, S.A. (1973). An annotated 

checklist of the native land mammals 

of the Northern Territory. Records of 

the South Australian Museum 16, 1- 

57. 

PWCNT (2001). Studies of the brushtailed 

tree-rat Conilurus penicillatus in 

Gurig National Park. (PWCNT, 

Darwin.) 

Taylor, R., Woinarski, J., Charlie, A., 

Dixon, R., Pracy, D., and Rhind, S.

(2004). Report on mammal survey of 

the Pellew Islands 2003. 

(Lianthawirriyarra Sea Ranger Unit, 

Department of Infrastructure, 

Planning and Environment, and 

Tropical Savannas CRC, Darwin) 

Woinarski, J.C.Z. (2000). The 

conservation status of rodents in the 

Top End of the Northern Territory. 

Wildlife Research 27, 421-435. 

Woinarski, J.C.Z., Milne, D.J., and 

Wanganeen, G. (2001). Changes in 

mammal populations in relatively 

intact landscapes of Kakadu National 

Park, Northern Territory, Australia. 

Austral Ecology 26, 360-370. 

Woinarski, J.C.Z., Armstrong, M., Price, 

O., McCartney, J., Griffiths, T., and 

Fisher, A. (2004). The terrestrial 

vertebrate fauna of Litchfield National 

Park, Northern Territory: monitoring 

over a 6-year period, and response to 

fire history. Wildlife Research 31, 1- 

10. 

Threatened Species Information Sheet

BRUSH-TAILED RABBIT-RAT BRUSH-TAILED TREE-RAT ...

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