The end third of Brush-tailed rock-wallaby’s tail is bushy, and typically brown to black, giving the animal its common name. One of the largest rock-wallabies, this animal, however, is not very big as compared to other wallaby species. In course of time, Brush-tailed rock-wallabies have adapted to their rugged habitat, becoming able to move swiftly through rocky terrains of their range. This is greatly due to soles on their flexible and well-padded hind feet, which have rough texture, providing good grip on rocks. In addition, the long and bushy tail of the animal helps the wallaby balance, when it leaps over boulders. Brush-tailed rock-wallabies are covered with long and thick fur, which is dull brown above, reddish-brown on the rump and lighter underneath. Black colored bands run along the pale grey flanks of the wallaby.
Small and scattered populations of these wallabies are found in Australia, namely, throughout south-eastern Queensland, eastern New South Wales and Victoria. The Brush-tailed rock-wallaby prefers boulder strewn outcrops and rocky habitats with nearby forest, woodland, heath or grassland.
Brush-tailed rock-wallabies are social and nocturnal animals. Choosing the most suitable area of their rocky habitat, Brush-tailed rock-wallabies form small colonies. These animals are highly territorial. Both males and females fiercely defend their home ranges as well as their den sites. Females in a colony are highly sociable towards each other: they are known to share their dens with other females and groom one another. Territories of adult males usually overlap with these of one or more adult females. These animals usually spend their daytime hours in shelters, where they find refuge from predators and rest. Brush-tailed rock-wallabies typically rest in vegetation, caves or overhang. They also spend time sunbathing on steep rocks. However, the period of highest activity is dusk and down. During this time, the wallabies come out of their shelters to feed; they can be observed moving amongst rocks, climbing up faces of cliffs and easily leap over, leaning on tree trunks.
These animals have polygynous mating system, where males mate with multiple females. Meanwhile, female individuals can mate with more than one male if their partner disappears from the colony. They have no specific breeding season. Gestation period lasts for about 30 days, yielding a single joey, which is born with undeveloped eyes, hind limbs and tail. As soon as born, the baby climbs up into the pouch of its mother, staying there for around 6 months. By the end of this period, the joey first comes out of the pouch. Then, for the next 7 - 20 days, the baby leaves the pouch multiple times, returning every time. And finally, at 9 months old, the young wallaby is completely weaned. Sexual maturity is reached at 20 months old in males, and by 18 months old in females.
Currently, the primary threat to the population of the Brush-tailed rock-wallabies is modification of their natural habitat due to: invasion of non-native plants; exotic herbivore grazing; drought; disease outbreaks; fires; clearance of habitat; tourism; residential development. The most dangerous predators of these wallabies are red foxes, which are able to find and reach once inaccessible shelters of these animals, causing high numbers of mortality.
According to the IUCN Red List, the total population size of Brush-tailed rock-wallabies is estimated to be between 15,000 and 30,000 individuals, including 20,000 mature individuals. They are classified as Vulnerable (VU), and numbers of their population are decreasing today.
Due to their herbivorous diet, Brush-tailed rock-wallabies help disperse the seeds of the fruit they eat.