The Woylie (Bettongia penicillata), also known as the Brush-tailed Bettong, is a member of the Potoridae family. Its habitat includes temperate forests and scrubs as well as arid shrublands and grasslands. It formerly ranged over all of southwest Western Australia, most of South Australia, the northwest corner of Victoria and across the central portion of New South Wales. It was abundant in the mid-19th century. By the 1920s it was extinct over much of its range. As of 1992 it was reported only from four small areas of Western Australia.
It is strictly nocturnal and is not gregarious. During the day it rests in a well-made and hidden nest which consists of grass and shredded bark. It digs out food such as bulbs, tubers and fungi with its strong foreclaws. The Woylie has an unusual diet for a mammal. Although it may eat bulbs, tubers, seeds, insects and resin, the bulk of its nutrients are derived from underground fungi, which can only be digested indirectly. In a portion of its stomach, the fungi are consumed by bacteria. These bacteria produce the nutrients that are digested in the rest of the stomach and small intestine.
It is able to use its tail, curled around in a prehensile manner, to carry bundles of nesting material.
The bettongs’ decline seems to have been caused by a number of factors. These include the impact of introduced grazing animals, clearing for agriculture, predation by introduced Red Foxes, and possibly changed fire regimes.