A species of very large rat (Mus giganteus), found in India and Ceylon. It does much injury to rice fields and gardens.

A ratlike marsupial animal (genus Perameles) of several species, found in Australia and Tasmania.

"Miserable as a bandicoot" - very miserable indeed, even though these marsupials are generally considered markedly cheerful.

any of various agile rat-like terrestrial marsupials of Australia and adjacent islands; insectivorous and herbivorous

A bandicoot is any of about 20 species of small to medium-sized, terrestrial marsupial omnivores in the order Peramelemorphia. The word bandicoot is an anglicised form of the Telugu word pandi-kokku, (loosely, pig-rat) which originally referred to the unrelated Indian Bandicoot Rat. The other two species of peramelemorphs are the bilbies.