MANGROVE MONITOR Varanus indicus (Daudin, 1802)
The Mangrove Monitor attains 1.5 metres and is found in mangrove and riverine habitats of Cape York, Queensland and coastal Northern Territory. This very distinctive lizard also occurs in New Guinea and other islands to the north of Australia.
Most specimens can be found when actively in search of their vertebrate food. When threatened the Mangrove Monitor usually takes to water where it will remain until danger passes.
Arnhem Land Aboriginals capture this lizard for food by canoeing down estuarine rivers and beating overhanging mangroves with long poles as they progress. The startled Monitor is then caught as it makes for the water.

The above was from the book Australian Reptiles and Frogs by Raymond Hoser and now available on a fantastic CD-Rom along with a vast amount of other information, papers and the like on reptiles, frogs and other wildlife.