The southern brown bandicoot, Isoodon obesulus, is a plump grayish-brown generalized omnivorous marsupial, mostly restricted to southern coastal regions of mainland Australia and to the island state of Tasmania. Two subspecies are recognized, with I. o. nauticus restricted to the islands off the South Australia coast. I. obesulus lives in a range of habitats, especially those providing some vegetative cover and with soils yielding earthworms, grubs, insects, and roots. Shrinking distributions toward coastlines and water courses suggest that I. obesulus may be less tolerant of drought than many marsupials. The illegal introduction of the red fox (Vulpes vulpes) into Tasmania in 2001 or 2002 and its potential establishment could lead to a decline in bandicoot populations similar to those seen in the past century on mainland Australia following fox introductions there.