Distribution: Northern Australia from the Kimberley to the west side of the Cape York Peninsula
Habitat: Coastal and inland waters such as rivers, creeks and billabongs
Description: The Mertens Water Monitor is dark brown to green with numerous small, cream to yellow spots on its body. Its underbelly is white or yellowish. Sometimes it has grey patterns on its chest and throat. The Mertens Water Monitor has a laterally compressed tail, which acts like a rudder when swimming.
Diet: The Mertens Water Monitor is a carnivore. It mainly feeds on fish, frogs and small mammals but will also eat insects and small terrestrial vertebrates.
In the Wild: As its name suggests, this monitor is rarely seen far from water. It is often found climbing on rocks or trees or basking on branches overhanging water. The Mertens Water Monitor has a very good sense of smell and often digs up prey when foraging for food. The Mertens Water Monitor has nostrils on the top of its head which allows it to remain partially submerged like an alligator or crocodile when looking for prey.
Threats: The introduced Cane Toad is a major threat to the Mertens Water Monitor, as they compete for food sources. Monitors also eat Cane Toads and die when they ingest the toxins in the toad’s skin.
At Perth Zoo: You can see Mertens Water Monitors in the billabong exhibit in the Australian Wetlands.
Did you know? The Mertens Water Monitor can stay underwater for several minutes. It is equipped with a special nostril valve that shuts tightly when the monitor dives under water.