The fat-tailed dunnart (Sminthopsis crassicaudata) is a species of mouse-like marsupial of the Dasyuridae, the family that includes the little red kaluta, quolls, and the Tasmanian devil.

S. c. centralis is found in Killalpannina (as Killalpanima, Lake Eyre East), near Etadunna, South Australia.

The habitats in which the species can be found include sparse grasslands, open shrublands and farmlands where there is considerable bare land.

The fat-tailed dunnart's diet includes insects such as beetles, spiders, small reptiles, and amphibians.

The fat-tailed dunnart is often eaten by other carnivores, including invasive foxes and cats, as well as other feral animals that share its environment.

Two conditions must occur in order for the fat-tailed dunnart to use daily torpor: low ambient temperatures and food shortage.

[5][7] This species does not use torpor for extended periods of time, thus the heart rate is variable and does not reach a steady state, such as seen in long-term torpidators.

[9] After awaking from a torpid state, these marsupials actively seek out areas in which they can bask in the sun to aid in this process.

During times of cold temperatures, the fat-tailed dunnart shares nests with rodent species such as the house mouse, (Mus musculus), to conserve heat.

[11] In August 2022, it was announced that the University of Melbourne will partner with Texas-based biotechnology company Colossal Biosciences to attempt to re-create the thylacine using the fat-tailed dunnart, one of its closest living relatives, and return it to Tasmania.