Mertens' Water Monitor
Encyclopedia
Mertens’ Water Monitor (Varanus mertensi), often misspelled Merten’s Water Monitor, is a member of the monitor lizard
family found in northern Australia
, and is a wide-ranging, active foraging, opportunistic predator of aquatic and riparian
habitats. It is named after German
herpetologist
Robert Mertens
.
, across the Top End
of the Northern Territory
and the Gulf Country
, to the western side of the Cape York Peninsula
in Far North Queensland
.
s through their range, through poisoning after eating them. Because of this they are listed as Vulnerable
under Northern Territory legislation.
Monitor lizard
Monitor lizards are usually large reptiles, although some can be as small as in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semiaquatic monitors are also known...
family found in northern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, and is a wide-ranging, active foraging, opportunistic predator of aquatic and riparian
Riparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by...
habitats. It is named after German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
herpetologist
Herpetology
Herpetology is the branch of zoology concerned with the study of amphibians and reptiles...
Robert Mertens
Robert Mertens
Robert Mertens was a German herpetologist. The Robert Mertens' day gecko is a species named after him, and he also postulated Mertensian mimicry....
.
Description
The monitor grows to a length of about one metre. It is dark brown to black above, with many cream to yellow spots. The underparts are paler – white to yellowish – with grey mottling on the throat and blue-grey bars on the chest. The tail is strongly compressed laterally, with a high median dorsal keel, and is about 1.5 times the length of head and body.Distribution and habitat
The monitor is found in coastal and inland waters across much of northern Australia, from the Kimberley region of Western AustraliaWestern Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, across the Top End
Top End
The Top End of northern Australia is the second northernmost point on the continent. It covers a rather vaguely-defined area of perhaps 400,000 square kilometres behind the northern coast from the Northern Territory capital of Darwin across to Arnhem Land with the Indian Ocean on the west, the...
of the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
and the Gulf Country
Gulf Country
The Gulf Country is the name given to the region of woodland and savanna grassland surrounding the Gulf of Carpentaria in north western Queensland and eastern Northern Territory on the north coast of Australia...
, to the western side of the Cape York Peninsula
Cape York Peninsula
Cape York Peninsula is a large remote peninsula located in Far North Queensland at the tip of the state of Queensland, Australia, the largest unspoilt wilderness in northern Australia and one of the last remaining wilderness areas on Earth...
in Far North Queensland
Far North Queensland
Far North Queensland, or FNQ, is the northernmost part of the Australian state of Queensland. The region, which contains a large section of the Tropical North Queensland area, stretches from the city of Cairns north to the Torres Strait...
.
Behaviour
The monitor is semi-aquatic, a strong swimmer and seldom far from water. It is often seen basking on mid-stream rocks and logs, and on branches overhanging swamps, lagoons and waterways throughout its range. When disturbed it drops into the water where it can stay submerged for long periods.Feeding
The monitor feeds both on land and in the water, mainly on fish, frogs and carrion, also taking terrestrial vertebrates and insects when available. It has a good sense of smell and may dig up prey when foraging, including the eggs of freshwater turtles.Breeding
The monitor lays eggs in a burrow, usually with egg-laying taking place early in the dry season and hatching in the following wet season. The eggs hatch within 200–300 days after laying, depending on temperature, with the hatchlings able to enter the water and swim immediately.Conservation and status
Mertens’ Water Monitors are threatened by the spread of Cane ToadCane Toad
The Cane Toad , also known as the Giant Neotropical Toad or Marine Toad, is a large, terrestrial true toad which is native to Central and South America, but has been introduced to various islands throughout Oceania and the Caribbean...
s through their range, through poisoning after eating them. Because of this they are listed as Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
under Northern Territory legislation.