Brush-tailed rock wallaby (Petrogale penicillata)
|Also known as:||Western rock wallaby|
|Size||Head-body length: 50 - 59 cm (2)|
Tail length: 50 – 70 cm (2)
Male weight: 5 – 11 kg (2)
Female weight: 4 – 9 kg (2)
Classified as Near Threatened (NT) on the IUCN Red List (1).
This agile marsupial has many adaptations to allow it to move swiftly through rugged habitat (2). The flexible, well-padded hindfeet have roughly textured soles, giving secure grip on rocks, and the long, bushy tail provides balance as they leap over boulders (2) (3). Their long, dense fur is typically dull brown above, reddish-brown on the rump, and lighter on the underparts. The flanks bear distinct pale grey and black stripes (2). As its name suggests, the end third of this rock wallaby’s tail is bushy, and is generally brown to black (2). Like other wallabies, female brush-tailed rock wallabies have a forward-opening pouch, in which the newborn infants develop, and four mammae (3),
The brush-tailed rock wallaby is endemic to Australia, where it occurs in small, isolated populations dotted across south-eastern Queensland, eastern New South Wales and Victoria (3).
In accordance with its name, this wallaby inhabits rocky areas and boulder strewn outcrops, where nearby forest, woodland, heath or grassland provide important cover (3).
Living in small colonies that occupy a suitable patch of rocky habitat, both male and female brush-tailed rock wallabies establish territories, which are vigorously defended. Each adult male territory may overlap with the territory of one or more adult females (2). Males are thought to have more than one female partner at a time, while females mate with only a single male, until he disappears from the colony and will then mate with another male. Female brush-tailed rock wallabies give birth to a single young, known as a joey, at a time, after a gestation period of approximately 30 days (2). With undeveloped eyes, hindlimbs and tail, the tiny joey immediately climbs up its mother’s fur into her pouch (4), where it will remain for the first six months of life (2). Following this period, 7 to 20 days are spent moving in and out of the pouch, and by the age of nine months, the joey is fully weaned. In the wild, brush-tailed rock wallabies have a life span of five to ten years (2).
The brush-tailed rock wallaby is most active during dusk and dawn, during which times it will move across rocks, scramble up cliff faces, and leap over leaning tree trunks with remarkable ease (3), as it travels to areas where it can feed on a variety of grasses and shrubs (2). During the drier, hotter summer months of Australia, this rock wallaby feeds on the juicy bark and roots of various trees, which provide sufficient moisture to allow the rock wallaby to exist for long periods without water (3). During the less active periods of the day, the brush-tailed rock wallaby can be found resting under the shelter of a cave, overhang or vegetation, or sunning themselves on steep rocks. These shelters also proved refuge from predators, such as foxes, dogs, cats, wedge-tailed eagles, (Aquilla audax) and possibly tiger quolls (Dasyuridae) (2).
Once one of the most widespread of the rock wallabies, this bushy-tailed species has been greatly reduced in both numbers and range (3). In the nineteenth and early twentieth centuries, this species was valued for its skin, as well as being thought of as an agricultural pest, and as a result hundreds of thousands were killed (3). Today, numerous threats continue to impact populations, including predation, competition, exotic plant invasion, habitat modification, fire, drought and disease (2).
Habitat modification is believed to be one of the most significant threats to this Vulnerable marsupial, with habitat clearance, exotic plant invasion, changed fire regimes, exotic herbivore grazing, and residential and tourist developments, all impacting and altering the brush-tailed wallaby’s habitat (2). Predation by introduced red foxes (Vulpes vulpes) is also considered to be one of the major reasons behind these declines, as these agile predators can reach the wallaby’s once inaccessible refuges (2).
Conservation of the brush-tailed rock wallaby has, to date, largely taken the form of red fox control programs. Fox control programmes are currently being undertaken in a number of areas, including Warrumbungles National Park, Yengo National Park and Goulburn River National Park (2). However, in 2008, the New South Wales National Parks and Wildlife Service published a recovery plan, which outlines further measures which are to be carried out with the aim of halting the decline in this species, and improving its threatened status. These actions include continuing existing and introducing new predator and introduced herbivore control programs, and continuing and expanding community-based conservation programs. Furthermore, captive populations of the brush-tailed rock wallaby in Australia have allowed important research to be carried out (2).
For further information on the conservation of the brush-tailed rock wallaby see:
- Brush-tailed Rock Wallaby Recovery Team:
- NSW Department of Environment and Climate Change:
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- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Gestation: the state of being pregnant; the period from conception to birth.
- Mammae: the organs of females that contain milk-producing glands.
- Marsupial: a diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.
- Territory: an area occupied and defended by an animal, a pair of animals or a colony.
IUCN Red List (December, 2009)