The Julia Creek dunnart is a small marsupial that is nocturnal and carnivorous, and is the biggest of the genus Sminthopsis, 19 species of which are found in Australia. It almost became extinct before being discovered in the 1930s. It was rediscovered in 1992 after people thought it had been exterminated by invasive animals such as the domestic cat and the European fox. Populations have increased slightly since that time, as Australians have begun killing stray cats.
The Julia Creek dunnart inhabits the Mitchell Grass Downs, as well as north-western Queensland, Australia in the Desert Uplands. It shelters within the cracking clay soils in the dry season or amongst low grass and shrubs after the summer rain. Its choice of habitat seems due to the density of cracks and holes and in the soil, instead of the season-dependent vegetation cover.
Julia Creek dunnarts are solitary and nocturnal, they shelter deep in cracks in the ground in the day and emerge at night to hunt. They seem to be very mobile and occupy stable home ranges of a size from 0.25 ha to 7.12 ha. This species can induce a hibernation-like state in times of famine in order to survive.
Julia Creek dunnarts are insectivores and eat different insects (silverfish, cockroaches, slaters and crickets), skinks, spiders, scorpions, centipedes, and long-tailed planigales.
Very little is known about the mating behavior in Julia Creek dunnarts. It is known that they breed in spring and summer. They make nests in grass tussocks, within dense cover. Two litters may be produced during an extended season if the environmental conditions are suitable. Gestation lasts 13 days and litters typically number eight. In captivity, females reach maturity at 17–27 weeks but may extend mating into a third year. The males reach maturity from 28–31 weeks, the females maturing earlier then males from the same litter. The later maturity of males may be a means of limiting inbreeding in small populations.
Exotic predators (especially foxes and cats), grazing by cattle and sheep, and the prickly acacia are major threats to these animals. Further threats include climatic factors, inappropriate fire regimes, and small population size.
No estimate of population size is available for this species, but it is very sparsely distributed within its range and scattered. Currently this species is classified as Near Threatened (NT) on the IUCN Red List and its numbers today are decreasing.
The Julia Creek dunnarts may affect predator populations, as items of prey.