The Julia Creek dunnart (Sminthopsis douglasi) is a marsupial with a buffy brown upperside and white underside. This dunnart has a body length of 100–135 mm with a tail of 60–105 mm to make a total length of 160–240 mm. Its weight is between 40 and 70 g. The length of the hind foot is 22–24 mm. The species has a dark brown triangle colour from above and below the eye with the point at the nose, and another dark stripe on top of the skull. A healthy dunnart has a carrot-shaped tail filled with fat stores.