The coloration of the upper parts of djoongari is a pale yellowish fawn interspersed with darker brown guard hairs.

Another specimen held at the British Museum, an old female obtained by F. M. Rayner during the voyage of HMS Herald in 1858, was designated as the holotype.

but suffered greatly after the arrival of Europeans and feral animals, and eventually its range became reduced to coastal sand dunes on Bernier Island, leaving it severely endangered.

In 2003 the Australian Wildlife Conservancy (AWC) released some Shark Bay mice onto Faure Island in the hope of creating another population.

Despite the presence of owls the reintroduction was successful and the population quickly grew to a larger size than that of Bernier Island, no longer leaving the species on the brink of extinction.

It is slightly smaller than a black rat, and quite social, living in small family groups of 4–8 that sheltered by day in a nest of soft, dry grass in a burrow.

[11] However, a 2021 genetic study found that it survived on small islands off the coast of Western Australia, in populations which were formerly thought to be their own species known as djoongari.