Brush-tailed rock-wallaby: cliff-hangers of the Great Divide

Name(s): Brush-tailed rock wallaby (Petrogale penicillata)

Size: Height: up to 600mm; tail length a shaggy 620mm. Weight: adults generally 5-8kg, but males can get up to 11kg.

Diet: Herbivore

Habitat/range: Rocky escarpments in the Great Dividing Range from southern Queensland to Eastern Victoria (and the Grampians in western Victoria!)

Conservation status: National conservation status currently under review. Brush-tailed rock wallabies are listed as Critically Endangered in VIC, Endangered in NSW, and Vulnerable in QLD. They no longer exist in the wild in the ACT.

Superpower/fun fact: Can balance on a knife edge and jump two metres high!

Nicknamed “The Shadow” after a 1943 children’s book by Leslie Rees, brush-tailed rock wallabies are a beautiful, athletic, and often elusive (hence the nickname) macropod of eastern Australia’s rugged mountain ranges.

Like all rock wallabies, they make their home in complex rocky outcrops. However, brush-tailed rock-wallabies take things to the extreme. While some species, particularly in northern and western Australia, can be found on relatively low rock piles, brush-tails really live up to the rock wallaby name. They cling to cliff edges in deep gorges, and happily hop around scree slopes and boulder fields among the mountain peaks of the Great Dividing Range. These cliffs and crags can be hundreds of metres high and in the words of A.B. Banjo Patterson, are truly “twice as steep and twice as rough”!

Brush-tailed rock wallabies flourish in habitat dominated by spectacular rocky peaks, vertical slopes, dark caves, precarious overhangs, and wild rivers. This is all thanks to the grip provided by the highly textured soles of their rubbery feet, and their agility and amazing jumping capabilities. Think of them as Australia’s mountain goat (but far cuter). They use their powerful hind legs to repeatedly ricochet off rock, easily traversing cliff faces and rock gullies, while using their long tails for balance and as a rudder to steer them.

To put this skill into perspective, 2.5-metre-high fences are needed to keep them contained when in captivity; anything less and they could clear it from a standing start. They have been seen balancing on tree limbs 8 metres up, with young sheltering among mistletoe, in tree hollows, or on the odd occasion, down rabbit warrens. Two years ago, one of the authors trapped an escapee off the gable of a house roof in the Adelaide Hills – just a walk in the park for a brushy!  These incredible aerial gymnasts could comfortably balance on the top edge of your bedroom door and so are quite at home on precipices overlooking terrifyingly sheer drops.

Unlike other rock wallaby species, the brush-tailed rock wallaby’s habitat extends into colder climates, with parts of their range in snow during winter months. To cope with this, they have a thick, shaggy rufus-black coat, a brushy tail (hence the name), and small, rounded ears to conserve heat. This only adds to the charisma of their round baby faces, striking cheek stripes, large hazel eyes, and long lashes.

Brush-tails are a shy species that tend to remain hidden, an easy feat in the rugged and difficult to access terrain in which they live. They have good reason to be cautious as they have to cope with both aerial (wedge-tailed eagles) and terrestrial (foxes, cats, dingoes, spotted-tailed quolls and even lace monitors) predators. Brush-tails rely on their steep terrain and boulder-ridden homes to provide protection from these predators, with mothers stashing their young deep in complex rocky jumbles. Unfortunately this isn’t always protection enough.

Following European settlement, hunting for the fur trade, disease and predation by exotic pests caused a dramatic decline in abundance of the species across their range. By the 1920s, they were even believed to be extinct in Victoria and southern New South Wales. But this charismatic mammal has always attracted passionate people who admire their agile grace and tenacious ability to survive, leading to remarkable stories of rediscovery and recovery. By the 1970s, multiple small and highly vulnerable colonies were uncovered in Victoria and southern NSW. The plight of the brush-tailed rock wallaby became better known, and the resulting struggle to save a species has led to several remarkable conservation innovations. As part of developing the assisted breeding technique called cross-fostering, tiny joeys from the Snowy (as small as two grams!) were flown first class from Canberra to Adelaide to be foster-reared by yellow-footed rock wallaby and tammar wallaby surrogate mothers. Their cryptic nature and inaccessible habitat in NSW have also led to them being the poster child for the development of a now commonly used non-invasive monitoring technique using faecal DNA.

Despite living on almost sheer drops, having to evade multiple predators, and attempting to recover from serious population declines, brush-tailed rock wallabies continue to defy the odds. One thing’s for sure, they really do live life on the edge!

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