Perentie

## Description

The perentie (Varanus giganteus ) is the largest monitor lizard or goanna native to Australia. It is the one of the largest living lizards on earth, after the Komodo dragon, Asian water monitor, crocodile monitor, and intersecting by size with Nile monitor. Found west of the Great 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 a least-concern species according to the International Union for Conservation of Nature.

Its status in many Aboriginal cultures is evident in the totemic relationships, and part of the Ngiṉṯaka dreaming, as well as bush tucker. It was a favoured food item among desert Aboriginal tribes, and the fat was used for medicinal and ceremonial purposes.

## Appearance

The Perentie is the largest monitor lizard native to Australia, and the fourth-largest living lizard on earth. It has a very strong tail and powerful legs with 5 clawed toes. The color pattern is brown with large cream or yellow rosettes.

## Distribution

Perenties are found in Western Australia, South Australia, the Northern Territory, and Queensland. They inhabit arid desert areas, rocky outcroppings, and gorges, with hard-packed soil and loose stones.

## Behavior

These lizards lead a solitary life; they generally avoid human contact and will 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 tail 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. When detected, perenties will either freeze (lying flat on the ground, and remaining very still until the danger has passed) or run. If cornered, this powerful carnivore will stand its ground and use its arsenal of claws, teeth, and whip-like tail to defend itself. They inflate their throats and hiss as a defensive or aggressive display, and strike at opponents with their muscular tails. Perenties will also lunge forward with open mouths, 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 from their mouths. Perenties are normally active hunters but may also hide and ambush prey when needed. They attack by either biting with their strong jaws or whipping the prey with their long, powerful tail; their tails are so strong, that they can easily break a dog's leg with a single blow. Once they bring their prey down, they shake it to death in their strong jaws and then swallow it whole. Perenties use their tails both offensively and defensively.

## Venom

In late 2005, University of Melbourne researchers discovered that all monitors may be somewhat venomous. 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 dragons, (V. komodensis), perenties (V. giganteus ), lace monitors (V. varius ), and spotted 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.

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 of squamate biochemical systems".

## Diet

Perenties are carnivores and scavengers and feed on a wide variety of prey. Depending on their size, they hunt insects, lizards, fish, birds, turtle eggs, small animals such as rats and rabbits, and carrion. Larger individuals will also hunt large animals, such as small kangaroos, wombats, and even lone dingoes.

## Reproduction

Perenties breed in spring and summer. Females lay eggs in deep sandy burrows or termite mounds. The clutch usually consists of 6 to 12 eggs and hatchlings appear 9-12 months later.

## Population

### Population threats

There are no major threats to perenties at present. However, these lizards were once a favored food item among desert Aboriginal tribes, and their fat was used for medicinal and ceremonial purposes.

### Population number

The IUCN Red List and other sources don’t provide the number of the perentie total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

### Ecological niche

Perenties are important predators and also scavengers in the ecosystem they live in. As these lizards feed on carrion they prevent the spread of disease and assist with a sort of “natural recycling”.