The Brush-tailed Rock-wallaby (Petrogale penicillata) is a critically endangered endemic Australian species. Once common – it was driven to the brink of extinction by European settlers and introduced species.

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Diprodontia
Family: Macropodidae
Genus: Petrogale
Species: penicillata

The Brush-tailed Rock-wallaby weighs 6 – 8 kilograms and stands around 60 cm tall. They have a brown coat with reddish hind legs, the face has a pale stripe on the cheeks, and the tail has the bushy end for which they are named. They exist in rocky outcrops and caves in scattered populations in Queensland, New South Wales and Victoria. The steep rock slopes provide a refuge, from which they can emerge to graze in the surrounding open eucalypt woodland.

The Brush-tailed Rock-wallaby populations are genetically distinct, and divided into three main groups: the northern group comprises Queensland and north-east New South Wales; the central group includes populations in the remainder of New South Wales; and the southern group is made up of the isolated Victorian population. The northern group is estimated to have a total of 10-20,000 individuals, the central group less than 900 animals, and there are only 20 or so individuals remaining in the Victorian population. Due to the genetic differences within the species, supplementing the southern populations with animals from the other two is not advisable, and could hasten the decline of the southern groups.

The decline of the species is attributed to several causes, most directly associated with European settlement. The factors cited include hunting; predation by foxes and feral dogs and cats; competition with goats and rabbits for food and shelter; weed invasion; changes in fire regimes; drought; and disease. Between 1884 and 1914 over half a million Brush-tailed Rock-wallabies were killed – both for their fur and because they were regarded as an agricultural pest.

A recovery program is underway. Populations are monitored and predator control is performed in many areas. Genetic research is vital to the survival of the species – it has already shown the inadvisability of importing animals from other populations to the most threatened Victorian group. Captive breeding programs are underway at Healesville Sanctuary and the Adelaide Zoo. Tragically, the very successful breeding and cross-species fostering programs at Tidbinbilla nature reserve have come to a halt – with 30 of the 35 individuals there recently killed in bushfires. This is a significant setback for the program, as Tidbinbilla had begun introducing some captive bred wallabies to the wild population. A community education program is also underway.

The Brush-tailed Rock-wallaby is listed as "Critically Endangered" in Victoria and "Vulnerable" in Queensland and New South Wales. I have been unable to find any data on the effects of the recent bushfires on the New South Wales and Victorian populations. When facts come to hand I will add them to this writeup.