Animal Spotlight: Perentie Monitor

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Via Australia Zoo

Taxonomy:

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Reptilia
  • Order: Squamata
  • Family: Varanidae
  • Genus: Varanus
  • Species: giganteus
  • Average Length: 5.8 – 6.6 ft (1.8 – 2 m)
  • Average Weight: 33 lbs (15 kg)
  • Oldest Known: 19.7 years

Perentie monitors only occur in the Australian deserts: from the central coast of Western Australia to arid western Queensland and into northern half of Southern Australia. Preferring arid habitats, the perentie digs its burrows in sandy ground and are most abundant around rocky outcrops as well as gorges and ranges. It also inhabits rocky ranges, flat-topped elevated land, semi-arid savanna, caves, sand ridges, and rock crevices. The monitor is also common on Barrow Island, off the coast of Western Australia, where it is an ecologically significant top predator.

Physical Description:

Also known as a monitor or a goanna, the perentie is Australia’s largest lizard. It has a creamy coloration, becoming browner on the upper parts, occasionally with a reddish tinge, with age. The body and tail are darkly speckled and have transverse bands of pale, dark-edged spots from the neck to two-thirds of the way down the tail. Its powerful legs are dark brown and end in five clawed toes while the tail is flat and extremely strong.Other than the black lines on the throat, the lizard’s long neck has unique spot patterns that can be used to identify individuals.

The perentie’s snout is long and is flattened at the end. And unlike other lizard species, the perentie has a forked tongue like a snake, which can constantly flick in and out. It picks up scents from the air, transferring them to the structure called the Jacobson’s organ, which is located on the roof of the mouth. The teeth are sharp and slightly curved.

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In late 2005, researchers from University of Melbourne discovered that perenties, among other monitors and iguanas, may be somewhat venomous. Previously, bites inflicted were thought to be simply prone to infection because of bacteria in the lizard’s’ mouth. But, these researchers have shown that the immediate effects are caused by mild venom.

Diet:

Perenties are carnivores and will eat almost anything they can overpower. This includes other reptiles, birds, mammals, and carrion. The monitor will supplement its diet with turtle eggs and insects. They are also significant predators to the introduced rabbit and house mouse.

Perenties do not chew their food. Instead, mouthfuls are swallowed whole, with a characteristic jerking motion. These lizards will track their prey by sight or by sensing with their tongue.

Behavior:

Like all monitors of the Varanus genus, it is able to effectively track its prey using its long tongue, which picks up chemical signals in the air. Mates may also be located in this way. Like other varanids, the perentie learns to recognise good locations for food and other resources, returning regularly to these sites when foraging. When prey is caught, it is shaken violently until dead, and then swallowed whole.

The perentie monitor is unique in its ability to run extremely fast over great distances. It will hold its legs underneath its body, walking erect like a mammal. In addition, it also capable of running solely on its hind legs, with its front legs tucked close to the body. This lizard is a fast, reaching speeds up to 25 miles (40 kilometers) per hour, enabling it to run solely on its hind legs. To reach such speeds, the perentie expands and contracts the sides of its neck, effectively making the throat behave like bellows, pumping air from the nostrils down to the lungs while it is running. In addition to this athletic ability, monitor lizards also have extremely good eyesight.

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In general, male perenties are territorial and will fight other males for access to a female. During combat, males will grasp each other with their forelegs while standing on their hind legs, trying to push their rival to the ground. When threatened, the perentie will often rise on its hind legs, swell its throat by distending their throats with air, and hiss loudly. They can also cause injury to the intruder by whipping it with their very strong tail, and by biting or scratching with their large teeth and claws. Defensive behavior includes lashing the tail, clawing, and hissing.

Courtship resembles that of other monitors. The male perentie licks and nuzzles the female, and several copulations will take place over a few days. Breeding in spring to early summer, the female perentie lays one clutch of six to twelve eggs per year. Reptile eggs are vulnerable to damage due to their thin casing, and are not fully impervious to water, allowing them to be laid in the absence of open water. To protect its eggs and keep them at constant optimum temperature and humidity, the perentie lays its eggs inside a termite nest. Termites maintain the temperature and humidity of their nests with the utmost vigilance, and the conditions are ideal for perentie eggs. After around three to nine months later, the brightly colored young will hatch.

Conservation and Threats:

perentie_map

There are no known threats to the perentie at present. The species has not yet been assessed by the IUCN and is listed as data deficient. However, it is listed on Appendix II of CITES as near threatened. This is not necessarily because it is currently threatened with extinction, but it may become so unless trade is closely controlled and monitored.

No specific conservation measures are currently known to be in place. But, in some parts of its range, all reptiles, including the perentie, are under protection.

Interesting Facts:

  • The perentie is the world’s fourth largest lizard.
  • The skin pattern of the perentie is said to be the inspiration for a particular style of Aboriginal woodcarving.
  • They are a delicious source of food for the desert Aboriginal people and Wedge-tailed eagles. Their fat is also used for medicinal and ceremonial purposes.Young perenties are vulnerable to snakes and other large goannas.
  • Goannas, the group the Perentie monitor belongs to, are among the world’s oldest lizard families and are thought to be highly intelligent.
  • In Australia, there are 25 different species of monitor, just less than half of the world’s known species of monitors.
  • Their status in many Aboriginal cultures is evident in the totemic relationships.

References + For More Reading:

Perentie Monitor

Arkive: Perentie (Varanus giganteus)

Australian Goannas, Our Monitor Lizards

BBC Nature: Perentie

IUCN: Perentie

Australia Zoo: Perentie

EOL: Perentie

Lifespan of a Goanna Lizard

Largest Australian Monitor

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