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Mertens' Water Monitor

Varanus mertensi

Australia's Threatened Species Category

Endangered

Listed since: 21/12/2023

IUCN's Threatened Species Category

Endangered

Listed since: 20/02/2017

Population trend: Decreasing

Other names: Mertens's Water Monitor

Priority species? No

The Australian government's Threatened Species Action Plan 2022-2032 selected over 100 priority species derived from consultation with threatened species experts and the wider community. While all species are important, focusing on a limited number of species can help target effort and resources so that outcomes can be achieved, measured and shared.

Description

Mertens� Water Monitor is a large and robust lizard that reaches up to 1.5m in total length. It is a semi-aquatic monitor that is well adapted to the water, having nostrils positioned on top of the snout and a long, strong tail for powerful swimming. It occurs patchily across tropical northern Australia, from the west Kimberley in Western Australia, across the Top End of the Northern Territory, to the wet tropics in far north Queensland. It usually eats freshwater crabs, fish, insects, amphipods, spiders and frogs, however, it will also consume most invertebrate and small vertebrate prey that can be subdued, including shrimps, crayfish, aquatic snakes, lizards, nestling birds, small mammals, caterpillars, and eggs.

Threats

The greatest threat to the long-term persistence of Mertens� Water Monitor is the invasive and toxic cane toad. Although they appear to be persisting across the Top End of the Northern Territory, there are few remnant sites elsewhere within this species� distribution where cane toads have established.