I should not have presumed and should have asked for more details of the location. It could also possibly be a wild Brown Rat and I cannot totally exclude a Pseudomys species.
As George said, R. fuscupes are found in areas of dense undergrowth, often with ferns and fallen logs.
Most of the terrestrial Australian mammal fauna has been around for around 100 million years. Rodents, probably a mouse-like ancestor, are a ‘late arrival’ at around 15 million years ago and have since evolved to into everything from water-rats to hopping mice. In all of these species, the females have only 4 nipples and all are located in the lower abdominal or inguinal (groin) areas. These rodents are referred to as the “old endemics”.
There are seven species of native rodents all belonging to the genus Rattus. These appear to have been derived from a common ancestor that arrived millions of years later than the original founding rodent stock. These seven species may have anywhere between 6 and 12 nipples, 6 of which are always located on the lower abdomen and the rest, if present, in the pectoral area. These rodents are referred to as the “new endemics”.
The Long–haired, Dusky and Cane-field Rats have 12 nipples. Bush, Swamp and Pale-field rat have 8 or 10 nipples. The Cape York Rat has 6 nipples. The Bush Rat subspecies “lutreolus” in SW Vic (sometimes split into two subspecies) has 10 nipples.
Black Rats usually have 10 nipples, Brown Rats 12.
Blue
UPDATE: Indeed I was too presumptuous. Well done Brown.snake – right on the money.
Just goes to show that there is no substitute for experience.