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).

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 south-eastern Australia, where it occurs in south-eastern Queensland, eastern New South Wales, and as a tiny population in the East Gippsland of eastern Victoria.

Native to Australia, brush-tailed rock-wallabies are distributed along rocky escarpments of the Great Dividing Range from southern Queensland to western Victoria. Although common in south-eastern Queensland and northern New South Wales, populations in the southern and western parts of the range have declined. Remnant populations in Victoria and western New South Wales are endangered. Only three colonies in south-eastern Australia remain, and estimates of the total wild population in this region are at fewer than 12 individuals.

Petrogale penicillata was introduced to Hawaii and New Zealand. In Hawaii, a small population of rock-wallabies, descended from two animals, has existed on the island of Oahu since 1916. In New Zealand, brush-tailed rock-wallabies were introduced in the 1870s and can be found on Kawau, Rangitoto, and Montutapu islands. On some of these islands rock-wallabies are regularly culled because they have reached pest proportions.

Biogeographic Regions: australian (Native ); oceanic islands (Introduced )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Native to mountainous regions of eastern New South Wales, Australia, where now scarce (Tomich 1986); suitable areas throughout Australia, including many nearby islands, but not Tasmania (Nowak 1991:96). Introduced (1916) in Hawaii (leeward Oahu; population apparently concentrated on northwestern side of Kalihi Valley) (Tomich 1986).

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).

Petrogale penicillata has a dull-brown back, paler chest and belly, a rufous rump and black, furry feet. They have a black axillary patch often extending as a dark stripe to the margin of the hindlegs. Their tail darkens distally with a prominent brush. Their pelage is long and thick, especially about the rump, flanks and base of tail. Animals from the northern part of the range tend to be lighter and have a less prominent tail brush. They have long tails, slightly longer than their head and body length. Head and body length averages 55.7 cm in males and 53.6 cm in females, while tail length averages 61.1 cm in males and 56.3 cm in females.

Range mass: 4.0 to 10.9 kg.

Range length: 45 to 58.6 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Habitat and Ecology

Systems

• Terrestrial

Brush-tailed rock-wallabies live on rock faces close to grassy areas and often in open forests. They prefer sites with numerous ledges, caves, and crevices. They typically occupy sites with a northerly aspect, in order to sun themselves in the morning and the evening. Originally widespread and abundant, brush-tailed rock-wallabies were found in suitable rocky areas in a wide variety of habitats, including rainforest gullies, wet and dry sclerophyll forest, open woodland, and rocky outcrops in semi-arid country.

Habitat Regions: temperate ; tropical ; terrestrial

Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest

Other Habitat Features: caves

Comments: Rocky ranges and boulder-strewn outcrops with an associated cover of forest, woodland, heath, or grassland; agile among rocks, moves awkwardly in the open (Nowak 1991). Rocky cliff faces, steep open slopes, dry ledge and cave habitat with southern exposure.

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).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Petrogale penicillata feeds largely on grasses, which comprise 35-50% of its total diet, but will supplement its diet with leaves, sedges, ferns, roots, bark, fruit, seeds and flowers. Brush-tailed rock-wallabies choose to forage in locations with more forbs and short green grasses. There is little seasonality of diet. Also, the relative proportions of different food types in the diet are vary little among regions, despite varying vegetation. This sugests definite food preference with little or no seasonal shortages of preferred foods. Since brush-tailed rock-wallabies eat a wide range of food items, they are likely buffered against drought and against competition with more specialized herbivores.

Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts; fruit

Primary Diet: herbivore (Folivore )

Comments: Diet consists mainly of grasses; also eats juicy bark and roots of various trees (Nowak 1991). Diet in Hawaii mainly grasses and Osteomeles (Kramer 1971).

When they were more widespread, brush-tailed rock-wallabies substantially affected agricultural plant species. In 1880, legislation was passed in New South Wales declaring kangaroos and wallabies as vermin. A bounty was offered on brush-tailed rock-wallabies, suggesting that they threatened agricultural production. They apparently invaded orchards and vegetable gardens with their ability to jump on top of fences, and fed heavily on the plants there. Additionally, it is possible that brush-tailed rock-wallabies help disperse the seeds of the fruit they eat. For instance, large numbers of the seeds of Persoonia linearis were found in the wallabies' faecal pellets collected in the spring.

Ecosystem Impact: disperses seeds

Since brush-tailed rock-wallabies exhibit very high fidelity to diurnally used sites, predators may find it easy to learn where to find them. Furthermore, because colonies are small (due to declining population size), fewer individuals are available to be alert in order to detect and warn of approaching predators. Since Petrogale penicillata has been observed to maintain a relatively constant level of vigilance regardless of surrounding vegetation, however, it has been suggested that these animals rely on early detection of predators. Additionally, brush-tailed rock-wallabies are much more agile than their predators.

Known Predators:

• Vulpes vulpes

Reportedly lives in small groups that have a defended territory; males have a linear dominance hierarchy (Nowak 1991).

Petrogale penicillata engages in allogrooming, where one animal bites and licks the fur of another animal, which may serve a role in reinforcing dominance status. Other examples of communicative behaviors include making vocalizations (a hissing cough sound), staring intensely, and aggressive behaviors such as nose jabbing (one animal thrusting its nose toward another animal). Males may examine potential female mates by approaching the female and sniffing her rump or cloaca.

Additionally, some evidence suggests that adult males deposit scent marks within their area of control.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Comments: Basically nocturnal; may emerge on warm afternoons to bask in the sun (Nowak 1991).

Captive brush-tailed rock-wallabies have lived over 11 years.

Average lifespan

Status: captivity: 11 years.

Average lifespan

Status: captivity: 14.4 years.

Maximum longevity: 14.3 years (captivity)

Brush-tailed rock-wallabies breed year round. The few matings that have been observed among Petrogale penicillata involve only females and males who are established on refuges. A notable feature of brush-tailed rock-wallabies, as well as other Petrogale species, is close and regular association between the refuge-guarding male and the females who use his refuge. Association involves mutual grooming and unusually high tolerance of proximity.

Though details are unavailable on brush-tailed rock-wallabies, most species of Macropodidae are promiscuous. Brush-tailed rock-wallabies have a different mating system than most related species in three respects: 1) a higher proportion of adult males are likely to take part in breeding and may do so for many years, 2) variance in male reproductive success is relatively low, and 3) only some weaned females, those able to establish themselves on a refuge, are likely to breed at all.

Mating System: polygynous

Females are sexually mature by 18 months, and males by 20 months. They breed all year, mating soon after giving birth. Development of the embryo is delayed until the pouch is vacated. Pregnancy lasts 31 days, after which a single young is born and attaches to one of the 4 teats in the pouch. The young remains in the pouch for about 29 weeks, then suckles at foot for about three months. In captive animals, post-partum estrous was typically observed on the same day as birth, even sometimes appearing within a few hours.

The process of birth has been observed on one occasion in the rock-wallaby Petrogale penicillata inornata. The female sat on the base of her tail, her body leaning forward in order to bring the head close to the urogenital opening and pouch. Birth was accompanied by a small amount of clear fluid and blood, which the mother cleaned as the newborn young went toward the pouch opening. It took 45 seconds for the infant to reach the pouch opening from the urogenital opening. The mother remained in the birth position for 10 more minutes, licking around the urogenital opening.

Breeding interval: The breeding interval is unknown, but females can enter estrous shortly after giving birth and breed throughout the year.

Breeding season: Brush-tailed rock-wallabies breed throughout the year.

Average number of offspring: 1.

Average gestation period: 31 days.

Average weaning age: 7 months.

Average time to independence: 7 months.

Average age at sexual or reproductive maturity (female): 18 months.

Average age at sexual or reproductive maturity (male): 20 months.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; embryonic diapause ; post-partum estrous

Average gestation period: 30 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 590 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 540 days.

There are few details about parental investment in Petrogale penicillata. Young remain in the mother's pouch for around 29 weeks, where they receive protection and milk. After leaving the pouch, the evicted young continue to suckle for about 3 months.

Parental Investment: altricial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

In Australian captives: gestation 30-32 days; pouch life about 7 months (189-227 days); sexually mature in 18 months (590 days in males, 540 days in females) (Johnson 1979, Nowak 1991). Births have been recorded in March, June August, and September; litter size normally is 1; has lived over 14 years in captivity (see Nowak 1991).

In many parts of New South Wales, Petrogale penicillata populations have been reduced to small, isolated colonies. Predation, notably by red foxes (Vulpes vulpes), an introduced species to Australia, appears to be the current major threat to Petrogale penicillata. Habitat degradation through vegetation and fire changes, competition with goats, rabbits and sheep, and vulnerability to drought and disease may also be involved. Brush-tailed rock-wallabies have been observed to leave properties where sheep were introduced, suggesting that the habitat-specific rock-wallabies were starved out by the much more ubiquitous sheep.

The observation of the dramatic decline of a wild colony at the Jenolan caves in central New South Wales led to the first concerted management response to the continuing decline of Petrogale penicillata. The colony was of unknown size but supplemented by the release of 88 locally enclosure-bred animals in 1988. Late in 1992, the remaining wild animals at Jenolan were trapped and transferred to a nearby enclosure with the goal of establishing a captive breeding program. Such captive breeding programs generally allow for a far greater degee of direct control than can be exercised with wild animals. The NSW National Parks and Wildlife service (NPWS) has responded to the ongoing decline of Petrogale penicillata by initiating a program incorporating: 1) A survey to locate all sites where Petrogale penicillata> is extant; 2) a community awareness and involvement campaign; 3) the development and implementation of Population Management Plans (PMPs) for extant sites; 4) on-going research into threats and impacts.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: near threatened

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G4 - Apparently Secure

Classified as Near Threatened (NT) on the IUCN Red List (1).

Population

Population Trend

Major Threats

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 Actions

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).

When brush-tailed rock-wallabies were more widespread in Australia, they were shot as agricultural pests. They were able to enter and feed in orchards, and vegetable gardens required fences several meters high to exclude them.

Negative Impacts: crop pest

Captive populations of Petrogale penicillata are the focus of behavioral, management and genetic research.

Positive Impacts: research and education

Comments: Subspecies purpureicollis and godmani formerly were regarded as distinct species (see Nowak 1991:97).

Individuals on Oahu reportedly do not resemble living Australian individuals or museum specimens--rapid evolution? (Conant 1988). However, genetic data indicate that the Petrogale in Hawaii represent typical P. penicillata and are not consistent with suggestions that the Hawaiian population represents a novel taxon (Eldridge and Browning 2002).

Peradorcas concinna sometimes has been included in the genus Petrogale.