The Fat-tailed Dunnart (Sminthopsis crassicaudata), is a species of mouse-like marsupial of the Dasyuridae family, the family includes the Little Red Kaluta, quolls, and the Tasmanian Devil. Its range in Australia is in diverse habitats except for the Kimberley region of Western Australia and northern Territory like Arnhem Land and Kakadu National Park, but avoids the Wannon and Mallee scrub habitats in Victoria. In the northeast of Victoria, the species can also be found in grassy woodlands and shrublands.
The Fat-tailed Dunnart has an average body length of 2.3 to 3.5 inches with a tail of 1.75 to 2.75 inches. Ear length is 0.55 to 0.63 inches. Its weight varies between 0.35 to 0.7 ounces. It is one of the smallest carnivorous marsupials. The tail becomes fat a few millimeters from the anus and right up to the tip of the tail.
This species breeds from July to February, with the young in the pouch from July to April. Gestation is for 13 days and the young remain in the pouch for 70 days with litter size on average 7.5 with a 33% infant death rate. They generally have 2 litters per year with females not breeding for the first year. The average life span of the female is 18 months, and male 15 months.
The Fat-tailed Dunnart’s diet includes insects such as beetles, spider larvae, small reptiles, and amphibians. It stores fat reserves in its carrot-shaped tail for times of food shortage.