| Perentie | |
|---|---|
_(10244734736).jpg) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Family: | Varanidae |
| Genus: | Varanus |
| Subgenus: | Varanus |
| Species: | V. giganteus |
| Binomial name | |
| Varanus giganteus (Gray, 1845) | |
 | |
| Distribution of the perentie | |
| Synonyms[2] | |
Hydrosaurus giganteus,Gray | |
Theperentie (Varanus giganteus) is a species ofmonitor lizard. It isone of the largest living lizards on earth, after theKomodo dragon,Asian water monitor, and theCrocodile monitor.[3][4] Found west of theGreat Dividing Range 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 aleast-concern species according to theInternational Union for Conservation of Nature.
Its status in manyAboriginal cultures is evident in thetotemic relationships, and part of theNgiṉṯakadreaming, as well asbush tucker. It was a favoured food item among desert Aboriginal tribes, and the fat was used for medicinal and ceremonial purposes.
British zoologistJohn Edward Gray described the perentie in 1845 asHydrosaurus giganteus, calling it the "gigantic water lizard".[5]George Albert Boulenger moved it to the genusVaranus.[6]
Within the monitor genusVaranus, it lies within the subgenusVaranus. Its closest relatives belong to a lineage that gave rise to thesand goanna and theArgus monitor.
Perenties are the largest living species of lizard inAustralia. Perenties can grow to lengths of 2.5 m (8 ft 2 in) and weigh up to 20 kg (44 lb), possibly up to 3 m (9 ft 10 in) and 40 kg (88 lb), making it the fourth-largest extant species oflizard (exceeded in size only by theKomodo dragon,Asian water monitor andcrocodile monitor).[7][8][9] However, perenties are very lean among large monitors, making it significantly less bulky than therock monitor at a similar size.
In late 2005,University of Melbourne researchers discovered that all monitors may be somewhatvenomous. 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 byKomodo dragons (V. komodensis), perenties (V. giganteus),lace monitors (V. varius), andspotted tree monitors (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.[10]
University of Washington 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 ofsquamate biochemical systems".[11]
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.
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 climb trees easily. They often stand on their back legs and tails to gain a better view of the surrounding terrain. This behavior, known as "tripoding", 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 attack. The bite of a perentie can do much damage, not only from the teeth but also because of the oral secretions.
The perenties areapex predators that do not have natural predators in their range.[12]They are highly active carnivores that feed on mostly reptiles, small mammals, and less commonly birds such asdiamond doves.[13] They hunt live prey, but also scavenge carrion. Reptilian prey includes mostly lizards (such asskinks andagamids) and more seldom snakes, but this species also displays a notable example ofintraguild predation, as it eats an unusually large number of other monitor lizard species such asridge-tailed monitors,black-headed monitors,Gould's monitors, and evenArgus monitors.[14][15][16] Perenties also eat smaller members of their own species; such is the case of a 2 m (6 ft 7 in) perentie killing and eating a 1.5 m (4 ft 11 in) perentie.[17] Other lizard prey includecentral bearded dragons andlong-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.[18] Although adults feed predominantly on vertebrate prey, young perenties eat mostly arthropods, especially grasshoppers and centipedes.[19][17][20]
Prey is typically swallowed whole, but if the food item is too large, chunks are ripped off for ease of consumption.[21]
The perentie can lay its eggs in termite mounds or the soil.[22]
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