Varanids or Varanidae are 'Monitor Lizards'.
Gouldii Gouldii are Sand Monitor and Gouldii Flavirufus are Desert Sand Monitors they are sub-species which the Desert form have nicer colours and patening, also the Desert Form on average grow to about 1.2m whereas the Gouldii Gouldii Grow to an average of 1.4-1.6m (Some have been know to reach 1.8m). Gouldii Flavirufus are mainly found in Central Australia, Gouldii Gouldii are found in most areas of Australia and are wide-spread across the land, therefore can withstand lower temperatures. Another difference between the two is that G. Flavirufus are harder to obtain than Gouldii Gouldii.