Indigenous to the Wallacean region of Indonesia, all members of Tiliqua gigas hail from humid lowland rainforests and scrubland, in contrast to their Australian relatives, Tiliqua scincoides, which prefer more semi-arid and dry grassland biomes. However, there may be a subpopulation of northern blue-tongues that do roam sections of humid rain & mangrove forests of Cape York Peninsula. Tho, such occurrences might just be temporary.
Other species that require higher humidity include the Tanimbar blue-tongue (T. s. chimaera) of Maluku Province, and a yet-to-be-described Tiliqua sp. that looks remarkably like the Northern blue-tongue.
