 The red fox has been implicated in the extinction and decline of several native Australian species, particularly those of the family Potoroidae including the desert rat-kangaroo.The spread of red foxes across the southern part of the continent has coincided with the spread of rabbits in Australia and corresponds with declines in the distribution of several medium-sized ground-dwelling mammals, including brush-tailed bettongs, burrowing bettongs, rufous bettongs, bilbys, numbats, bridled nail-tail wallabies and quokkas.Most of these species are now limited to areas (such as islands) where red foxes are absent or rare.