The desert monitor is the most northerly distributed monitor species and one of the largest reptiles in its expansive range. The body is long and robust, with sturdy limbs, and a long, powerful tail which can be used liked a whip in defence. The nostrils of this species are particularly distinctive, comprising diagonal slits much closer to the eye than the tip of the snout. Colouration is highly variable, but is always far more vivid in juveniles, which are generally yellow or orange with bold black bands running across the body and tail. As the desert monitor ages its colour and markings fade, becoming light brown, yellow or dark grey, with faint or non-existent banding. In some adults the upperside may be marked with creamy spots and mottling or with small, dark spots extending to the tail and throat. This species is divided into three subspecies which occupy distinct geographical regions and can be identified by size, tail shape, and the number of bands on the body and tail. Varanus griseus griseus has a rounded tail and highest number of bands, Varanus griseus caspius reaches the largest size and has a laterally compressed tail, while Varanus griseus koniecznyi is the smallest subspecies and has the fewest bands.