Australia’s Second-Smallest Rock-Wallaby Reappears in a Region Where It Had Not Been Seen for 50 Years

The second-smallest rock-wallaby in the world is about as long as a loaf of bread. On its strong hind legs, it hops around rocky outcrops, cliffs and crevices, using the rough pads on its feet to grip sheer rock. By day, the species stays hidden from predators, and by night, it comes out to feed.

This secretive and rarely seen creature, called the nabarlek, is endangered, put at risk by shifting fire regimes and introduced predators. But in a small spot of hope for the marsupial, Australian conservationists and the Dambimangari Aboriginal Corporation recently captured the species on camera at two sites in Western Australia where it had not been scientifically recorded before. Both lie in a remote region where the nabarlek had not been documented for 50 years.

Potter tells Smithsonian magazine that this unique trait may be linked to its diet of tough shrubs and grasses. Finding a nabarlek is difficult. And once scientists have detected a wallaby that fits the animal’s description, verifying that it’s the target species is no easy task, either.

The nabarlek looks nearly identical to the monjon (another small rock-wallaby that shares its range), and its genes very closely resemble those of the short-eared rock-wallaby. So, to confirm their discovery, the team took multiple steps, using both camera trap imagery and genetic analysis to rule out the presence of these other creatures. First, they set out five cameras that operated at night, triggered by the motion of nearby animals.

They looked through the resulting photos to determine that the short-eared rock-wallaby is not found at the sites, assuring them that its similar-looking DNA would not be confused with that of the nabarlek. The short-eared rock-wallaby can easily be dismissed with images, because it doesn’t look the same as the nabarlek. Then, to make sure that the photographed wallabies were indeed nabarlek rather than the roughly identical monjon, researchers collected scat samples from the site to analyze their DNA.

These results came back with positive news for conservation: The elusive nabarlek had been found. On paper, the nabarlek’s range includes parts of northern and northwestern Australia. The new wallaby detections were in the Kimberley, a vast expanse of plateau, rivers and canyons on the northern coast of Western Australia.