In the wild, it is now restricted to a very small range in mainland south-western Western Australia, where it has become rare, and on two fox-free islands off the coast: Bald Island and Rottnest Island—which is its stronghold. On Rottnest it is common and occupies a wide range of habitats, ranging from semi-arid scrub to cultivated gardens.
Quokkas are the only member of the genus Setonix. They are 40 to 54 cm long with a 25 to 30 cm tail—which is rather short for a macropod. They have a stocky build, rounded ears, and a short, broad head. Although looking rather like a very small, dumpy kangaroo, they can climb small trees and shrubs. Their coarse fur is a grizzled brown colour, fading to buff underneath.
Quokkas are gregarious and gather in large groups where food is available: primary items are grasses, sedges, succulents and foliage. They breed at any time on the mainland, but in late summer on Rottnest.
Although numerous on the small offshore islands, they have a very restricted range and are classified as vulnerable. On the mainland, where they must contend with introduced foxes, they require dense ground cover for refuge.