The perentie (''Varanus giganteus'') is the largest
monitor lizard
Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recogn ...
or
goanna
A goanna is any one of several species of lizards of the genus '' Varanus'' found in Australia and Southeast Asia.
Around 70 species of ''Varanus'' are known, 25 of which are found in Australia. This varied group of carnivorous reptiles ranges ...
native to
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
. It is
one of the largest living lizards on earth, after the
Komodo dragon
The Komodo dragon (''Varanus komodoensis''), also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest extant ...
,
Asian water monitor
The Asian water monitor (''Varanus salvator'') is a large varanid lizard native to South and Southeast Asia. It is one of the most common monitor lizards in Asia, ranging from coastal northeast India, Bangladesh, Sri Lanka, mainland Southeast A ...
,
crocodile monitor
''Varanus salvadorii'', also known as the crocodile monitor, Papuan monitor and Salvadori's monitor, is a species of monitor lizard endemic to New Guinea. It is the largest monitor lizard known from New Guinea, and is one of the longest lizard ...
, and intersecting by size with the
Nile monitor
The Nile monitor (''Varanus niloticus'') is a large member of the monitor family (Varanidae) found throughout most of Sub-Saharan Africa and along the Nile, with invasive populations in North America. The population in West African forests and sa ...
.
Found west of the
Great Dividing Range
The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills, that runs rough ...
in the arid areas of Australia, it is rarely seen, because of its shyness and the remoteness of much of its range from human habitation. The species is considered to be a
least-concern species
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
according to the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
.
Its status in many
Aboriginal cultures is evident in the
totem
A totem (from oj, ᑑᑌᒼ, italics=no or ''doodem'') is a spirit being, sacred object, or symbol that serves as an emblem of a group of people, such as a family, clan, lineage, or tribe, such as in the Anishinaabe clan system.
While ''the wo ...
ic relationships, and part of the
Ngiṉṯaka
Ngiṉṯaka (), also spelled Ngintaku, is a giant perentie lizard Ancestral Being from Aṉangu and Pitjantjatjara religion and mythology. It is associated with Angatja, an area along an important songline.
Ngiṉṯaka is one of the two major ...
dreaming, as well as
bush tucker
Bush tucker, also called bush food, is any food native to Australia and used as sustenance by Indigenous Australians, the Aboriginal and Torres Strait Islander peoples, but it can also describe any native flora or fauna used for culinary or ...
. It was a favoured food item among desert Aboriginal tribes, and the fat was used for medicinal and ceremonial purposes.
Taxonomy
British zoologist
John Edward Gray
John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for ...
described the perentie in 1845 as ''Hydrosaurus giganteus'', calling it the "gigantic water lizard".
George Albert Boulenger
George Albert Boulenger (19 October 1858 – 23 November 1937) was a Belgian-British zoologist who described and gave scientific names to over 2,000 new animal species, chiefly fish, reptiles, and amphibians. Boulenger was also an active botani ...
moved it to the genus ''Varanus''.
Within the monitor genus ''
Varanus'', it lies within the subgenus ''Varanus''. Its closest relatives belong to a lineage that gave rise to the
sand goanna
The sand goanna (''Varanus gouldii'') is a species of large Australian monitor lizard, also known as Gould's monitor, sand monitor, or racehorse goanna.
Taxonomy
John Edward Gray described the species in 1838 as ''Hydrosaurus gouldii'', noting ...
and the
Argus monitor
The yellow-spotted monitor (''Varanus panoptes''), also known as the Argus monitor, is a monitor lizard found in northern and western regions of Australia and southern New Guinea.
Taxonomy
The first description of the species was provided in a ...
.
Description
The lizard can grow up to long, although the typical length is around and weigh up to —maximum weight can be over , rivaling the
rock monitor
The rock monitor (''Varanus albigularis'') is a species of monitor lizard in the family Varanidae. The species is endemic to Central, East, and southern Africa. It is the second-longest lizard found on the continent, and the heaviest-bodied; lo ...
for the title of the fifth-largest lizard. However, perenties are relatively lean lizards and are less bulky than either the Komodo dragon or the Asian water monitor. The
Nile monitor
The Nile monitor (''Varanus niloticus'') is a large member of the monitor family (Varanidae) found throughout most of Sub-Saharan Africa and along the Nile, with invasive populations in North America. The population in West African forests and sa ...
can also compete in size, in some exceptional cases reaching more than 2.4 m in length.
Venom
In late 2005,
University of Melbourne
The University of Melbourne is a public research university located in Melbourne, Australia. Founded in 1853, it is Australia's second oldest university and the oldest in Victoria. Its main campus is located in Parkville, an inner suburb nor ...
researchers discovered that all monitors may be somewhat
venomous
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
. Previously, bites inflicted by monitors were thought to be prone to infection because of bacteria in their mouths, but the researchers showed that the immediate effects are caused by mild envenomation. Bites on the hand by
Komodo dragon
The Komodo dragon (''Varanus komodoensis''), also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest extant ...
s (''V. komodensis)'', perenties (''V. giganteus''),
lace monitor
The lace monitor or tree goanna (''Varanus varius'') is a member of the monitor lizard family native to eastern Australia. A large lizard, it can reach in total length and in weight. The lace monitor is considered to be a least-concern species ...
s (''V. varius''), and
spotted tree monitor
''Varanus timorensis'', the Timor monitor or spotted tree monitor, is a species of small monitor lizards native to the island of Timor and some adjacent islands.
Taxonomy
Kimberley rock monitors (''Varanus glauerti''), banded tree monitors (''V ...
s (''V. scalaris'') have been observed to cause swelling within minutes, localised disruption of blood clotting, and shooting pain up to the elbow, which can often last for several hours.
University of Washington
The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington.
Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...
biologist Kenneth V. Kardong and toxicologists Scott A. Weinstein and Tamara L. Smith have argued that the suggestion of venom glands "... has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to the scientists "... reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". They concluded, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of
squamate
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...
biochemical systems".
Distribution and habitat
Perenties are found in the arid desert areas of Western Australia, South Australia, the Northern Territory, and Queensland. Their habitats consist of rocky outcroppings and gorges, with hard-packed soil and loose stones.
Behaviour and ecology
Perenties generally avoid human contact and often retreat before they are seen. Being able diggers, they can excavate a burrow for shelter in only minutes. Their long claws enable them to easily climb trees. They often stand on their back legs and tails to gain a better view of the surrounding terrain. This behaviour, known as "
tripoding
A tripod stance is a behaviour in which quadruped animals rear up on their hind legs and use their tail to support this position. Several animals use this behaviour to improve observation or surveillance, and during feeding, grooming, thermoregu ...
", is quite common in monitor species. Perenties are fast sprinters, and can run using either all four legs or just their hind legs.
Typical of most goannas, the perentie either freezes (lying flat on the ground, and remaining very still until the danger has passed) or runs if detected. If cornered, this powerful carnivore stands its ground and uses its arsenal of claws, teeth, and whip-like tail to defend itself. It can inflate its throat and hiss as a defensive or aggressive display, and can strike at opponents with its muscular tail. It may also lunge forward with an open mouth, either as a bluff or as an attack. The bite of a perentie can do much damage, not only from the teeth, but also because of the oral secretions.
Feeding
![Perentie & Echidna](https://upload.wikimedia.org/wikipedia/commons/7/77/Perentie_%26_Echidna.jpg)
The perenties are
top predators
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...
that do not have natural predators in their range.
They are highly active carnivores that feed on mostly reptiles, small mammals, and less commonly birds such as
diamond dove
The diamond dove (''Geopelia cuneata'') is a resident bird in Australia. The dove predominantly exists in areas near water but which are lightly arid or semi-arid in nature, being Central, West and Northern Australia. They are one of Australia's ...
s. They hunt live prey, but also scavenge carrion. Reptilian prey includes mostly lizards (such as skinks and agamids) and more seldom snakes, but this species also displays a notable example of
intraguild predation
Intraguild predation, or IGP, is the killing and sometimes eating of a potential competitor of a different species. This interaction represents a combination of predation and competition, because both species rely on the same prey resources and a ...
, as it eats an unusually large number of other monitor lizard species such as
ridge-tailed monitors,
black-headed monitor
The black-headed monitor or black-tailed monitor (''Varanus tristis'') is a relatively small species of monitor lizards native to Australia. It is occasionally also called the mournful monitor, freckled monitor (''Varanus tristis orientalis'') o ...
s,
Gould's monitors, and even
Argus monitor
The yellow-spotted monitor (''Varanus panoptes''), also known as the Argus monitor, is a monitor lizard found in northern and western regions of Australia and southern New Guinea.
Taxonomy
The first description of the species was provided in a ...
s. Perenties also eat smaller members of their own species; such is the case of a 2-m perentie killing and eating a 1.5-m perentie.
Other lizard prey include
central bearded dragon
The central bearded dragon (''Pogona vitticeps''), also known as the inland bearded dragon, is a species of agamid lizard found in a wide range of arid to semiarid regions of eastern and central Australia.
Taxonomy
''Pogona vitticeps'' was fi ...
s and
long-nosed water dragons. Coastal and island individuals often eat a large number of sea turtle eggs and hatchlings, and hide under vehicles to ambush scavenging gulls. Mammalian prey includes bats, young kangaroos & other small marsupials, and rodents. They have also been occasionally seen foraging for food in shallow water. They are able to kill kangaroos and dismember those too large to be swallowed whole using their powerful forelimbs and claws. Although adults feed predominantly on vertebrate prey, young perenties eat mostly arthropods, especially grasshoppers and centipedes.
Prey is typically swallowed whole, but if the food item is too large, chunks are ripped off for ease of consumption.
Breeding
The perentie can lay its eggs in termite mounds or in the soil.
Gallery
Image:Perentie Lizard Perth Zoo SMC Spet 2005.jpg, A perentie in the Perth Zoo
Perth Zoo is a zoological park in South Perth, Western Australia. The zoo first opened in 1898 and by 2011 housed 1258 animals of 164 species and an extensive botanical collection.
It is a full institutional member of the Zoo and Aquarium Ass ...
, Western Australia
Image:Perentie closeup.png, Closeup of a perentie in the wild
Image:Perentie.jpg, In Australia's Red Centre
Image:Perentie Lizard Pair.jpg , Pair of perenties in Perth Zoo
References
*
Further reading
* Cogger, H. (1967). ''Australian Reptiles in Colour''. Sydney: A. H. & A. W. Reed,
External links
{{Taxonbar, from=Q932293
Varanus
Reptiles of Western Australia
Reptiles described in 1845
Taxa named by John Edward Gray
Reptiles of the Northern Territory
Reptiles of Queensland
Monitor lizards of Australia
Apex predators