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:
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
Captive brush-tailed rock-wallabies have lived over 11 years.
Average lifespan
Status: captivity: 11 years.
Average lifespan
Status: captivity: 14.4 years.
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
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 )
An apparently narrow hybrid zone has formed between Petrogale penicillata and Petrogale herberti. In this zone, at the north of Petrogale penicillata's range, some female hybrids are fertile, which allows limited gene exchange between the two populations. This exchange is not widespread, however, allowing each species to retain its genetic identity.
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 ; tactile ; acoustic ; chemical
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
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
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
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 )
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); sexual ; 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)
The brush-tailed rock-wallaby or small-eared rock-wallaby (Petrogale penicillata) is a kind of wallaby, one of several rock-wallabies in the genus Petrogale. It inhabits rock piles and cliff lines along the Great Dividing Range from about 100 km north-west of Brisbane to northern Victoria, in vegetation ranging from rainforest to dry sclerophyll forests. Populations have declined seriously in the south and west of its range, but it remains locally common in northern New South Wales and southern Queensland.[4] However, due to a large bushfire event in South-East Australia around 70% of all the wallaby's habitat has been lost as of January 2020.
In 2018, the southern brush-tailed rock wallaby was declared as the official mammal emblem of the Australian Capital Territory (ACT), although it has not been seen in the wild in the ACT since 1959.[5]
Petrogale penicillata was first described by John Edward Gray in 1827.[3] The taxon has been named for a species complex, the Petrogale penicillata-lateralis group, the systematics of which continued to be resolved.
A species of Petrogale, rock wallabies have a dense and shaggy pelage that is rufous or grey brown. The tail is 500 to 700 millimetres long, exceeding the 510 to 580 mm combined length of the head and body. The colour of the tail is brown or black, the fur becoming bushy towards its shaggy, brush-like end. The weight range is from 5 to 8 kilograms. The upper parts of this wallaby's pelage is either entirely rufous-brown, or a grey brown over the back and shoulders with brown fur at the thigh and rump. The paler under parts may feature a white blazon on the chest. Very dark fur covers the lower parts of the limbs, paws and feet, and on the sides beneath the fore limbs of the animal; a whitish stripe may appear along the side of the body.[6]
The coloration of the species in the northern parts of population is paler and fur is shorter in length. The black-footed and flanked species Petrogale lateralis, which occurs in central Australia, is distinguished by its larger size and the shorter and darker fur of the tail and hind parts. Herbert's rock-wallaby (P. herberti) overlaps in the northern range of this species, their coloration is greyer than the warm brown of this species and lighter at the darker features of the limbs; the tail of that species also lacks the blackish features and bushy end.[6] The pads of the feet are well developed and their coarse texture allows good traction on rock surfaces.[7]
The species is able to negotiate difficult rocky terrain with great agility, their compact yet powerful build is assisted by counter-balancing the long tail and feet suited to holding the animal at precarious edges and on inclined surfaces. The species favours north facing refuges, and while largely nocturnal in venturing out from shelter they will bask in winter sun for short periods. Procreation is founded on breeding females utilising a single male for insemination, with births that occur throughout the year. Groups in cooler latitudes or higher altitudes may tend to reproduce in a period between February and May. The females of the colony cohere as maternal groups, with male progeny moving to other groups within the colony or migrating to another location. Individual foraging territories for the species are around 15 hectares, perhaps more for males.[7]
Found along the Great Dividing Range in fragmented populations that remain after its historical contraction in range from the east and south. The southern edge of the range is the Grampians, and no further west than the Warrumbungles range in New South Wales. The northernmost groups have remained less affected by ecological changes, these are found in southeast Queensland.
Petrogale penicillata shelters during the day in rocky habitat, within vegetation or cavities of preferably complex terrain that allows them to find cooler temperatures and to elude or remain inaccessible to predators. Their great agility while hopping and climbing provides opportunities at ledges, cliff-faces, overhangs, caves and crevices.[7]
As part of the acclimatisation movement of the late 1800s, governor Grey introduced this and four other species of wallabies (including the rare parma wallaby) to islands in Hauraki Gulf, near Auckland, New Zealand, where they became well-established. In modern times, these populations have come to be viewed as exotic pests, with severe impacts on the indigenous flora and fauna. As a result, eradication is being undertaken, after initial protection for review of their Australian populations and the return of some wallabies to Australia. Between 1967 and 1975, 210 rock-wallabies were captured on Kawau Island and returned to Australia, along with thousands of other wallabies.[8] Rock-wallabies were removed from Rangitoto and Motutapu Islands during the 1990s, and eradication is now underway on Kawau. Another thirty-three rock-wallabies were captured on Kawau during the 2000s, and returned to Australia, before eradication began.[9][10]
In 2003 some Kawau brush-tails were relocated to the Waterfall Springs Conservation Park north of Sydney, New South Wales, for captive breeding purposes.
Due to an escape of a pair in 1916, a small breeding population of the brush-tailed rock-wallabies also exists in the Kalihi Valley on the island of Oahu in Hawaii.
Attempts at reintroduction into the Grampians National Park during 2008-12 were not successful, largely due to fox predation.[11] Nevertheless, March 2017 saw the emergence of a fourth offspring, bringing the total number of rock–wallabies present within the Grampians National Park to eight.[12]
The Brush-tailed rock wallaby was once common throughout South-East Australia, but due to clearing of native habitat, exotic plant introduction, predation by introduced species and changing fire patterns as a result of climate change they have been wiped out from much of their Southern and Western ranges.
In late 2019 fierce bushfires swept through New South Wales and Victoria, burning protected areas inhabited by the wallaby. It is estimated that 70% of all brush-tailed rock-wallaby habitat was destroyed. In the aftermath of the fires in Victoria, where the wallaby was thought to have been hunted to extinction by the early 20th century by settlers who prized its fur and skin, until some who had survived were discovered in the Grampians in 1970,[13] a colony of 13 has been detected in the Grampians National Park while a further 50 are known to exist in the Snowy River National Park.[14]
The brush-tailed rock-wallaby or small-eared rock-wallaby (Petrogale penicillata) is a kind of wallaby, one of several rock-wallabies in the genus Petrogale. It inhabits rock piles and cliff lines along the Great Dividing Range from about 100 km north-west of Brisbane to northern Victoria, in vegetation ranging from rainforest to dry sclerophyll forests. Populations have declined seriously in the south and west of its range, but it remains locally common in northern New South Wales and southern Queensland. However, due to a large bushfire event in South-East Australia around 70% of all the wallaby's habitat has been lost as of January 2020.
In 2018, the southern brush-tailed rock wallaby was declared as the official mammal emblem of the Australian Capital Territory (ACT), although it has not been seen in the wild in the ACT since 1959.
