Heath Goanna Fact File
Wild 30 years
Captive 30 years
The heath goanna is a large species of monitor lizard found across the southern regions of Australia. They are Australia's most cold tolerant monitor.
Across the body their scales are colored slate grey with bands of yellow, orange and cream running down the body. At the end of the body is a long tail. Hatchlings are patterned with more intense oranges.
Females will deposit their eggs in to a termite nest which they are sealed inside. This provides the perfect temperatures for incubation along with a ready food source when the young hatch in the spring.
Removal of termite mounds, habitat clearing and vehicle strikes have all contributed to the decline of these lizards.
Learn more about the heath goanna by reading on below.
Heath goannas are a slate grey color with bands of yellow, orange or cream spots running down the body. They have a white belly. A black stripe runs out from the eye and down the neck.
At the end of the body is a strong tail which is long and has a distinct dorsal ridge. The tail is blackish with bands along its length which are cream or yellow in color. The tip of this tail is slate gray in color.
Juvenile animals have bolder orange marking’s which fade as they grow.
An adult male heath goanna can reach a length of 1.5m (5ft) long with a weight of up to 1.9kg (4lbs). Females may be as little as half the size of the male.
Australia is the native home of the heath goanna. Here they are found across Western Australia, South Australia, New South Wales, the Australian Capital Territory and Victoria.
They have the southernmost range of any Australian monitor and are the most cold tolerant of any Australian monitor speices.
Habitats occupied by the heath goanna include woodland, heath, sclerophyll forest and temperate forest. They prefer areas with sandy soil.
They use burrows to hide and rest. These may be hollow logs, rock crevices or a burrow which has been made by themselves or another monitor. They may also make use of mammal burrows such as a rabbit warren.
Their home range can be anywhere from 80 to 1000 hectares in size. They are territorial and prevent entry by other goannas in to this territory.
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Heath goannas will typically begin their mating period around the longest day of the year. Mating take’s place over the next four to six weeks.
The female will lay up to 14 eggs 21 days after her last mating.
These are deposited in a termite mound during summer. It may take up to 2 days for the female to excavate a suitable chamber in the termite mound in which to deposit her eggs. Once the female lay’s her eggs termites will quickly begin to repair the damage which seals the eggs inside. If they do not she will backfill the chamber.
Over autumn and winter these eggs are maintained at a constant temperature and humidity inside the termite mound. They will hatch in the spring.
Following hatching the juvenile heath goannas dig themselves out of the mound. In some instances, the mother may also return to dig the hatchling’s out of the termite mound. The hatchlings will live within the mound to feed on the termite’s it houses for the first few days of their life.
Only one in twelve hatchlings’ will survive to one year of age.
Sexual maturity is reached at 9 years’ old. Due to the high energy demands of breeding, females typically rest a year in between breeding attempts.
Rosenberg’s monitors are solitary animal’s only coming together for breeding season.
They are active by day. Their dark coloration assist’s with warming up in the colder region’s where they live.
Predators and Threats
Natural predators of the heath goanna include birds and snakes. Juvenile heath goannas may be preyed upon by adult monitor’s.
Introduced predators such as cats, dogs and red foxes eat heath goannas.
When threatened they tend to run along the ground unlike the similar lace monitor which will flee up a tree.
Their habitat is being destroyed including termite mounds being removed which leaves them without a suitable place to lay eggs. This habitat is also increasingly fragmented which leaves these animals at risk as they need large areas to find food.
Rosenberg’s monitors are regular road kill victims. As more roads in their habitat are sealed and speed limits increased the rate at which these animal’s die increase’s.
In parts of their range, mainly the east, they are confirmed to be declining due to these threats but the overall population trend is yet to be confirmed.
The heath goanna is also known as the heath monitor, Rosenberg’s goanna and Rosenberg's monitor.
Heath goannas were first described by a German herpetologist in 1957. Originally they were considered a subspecies of the sand goanna (Varanus gouldii) but in 1980 became their own species.
Studies are ongoing to determine if these reptiles are actually two unique species with some differences present in a population in the eastern states.
Cody Pope, CC BY-SA 2.5 <https://creativecommons.org/licenses/by-sa/2.5>, via Wikimedia Commons
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Paul Asman and Jill Lenoble, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
Swanson, S. (2014). Field Guide to Australian Reptiles. New South Wales. Pascal Press.
Smith, James. (2016). Wildlife of Greater Adelaide. Stepney. Axiom Publishers.
Bennett, D. and Sweet, S. (2010). Varanus rosenbergi (Heath Monitor, Southern Heath Monitor). [online] Iucnredlist.org. Available at: http://www.iucnredlist.org/details/178031/0 [Accessed 13 Feb. 2018].
Department of Environment, Water and Natural Resources. (2015). Help Save the Heath Goanna. [Brochure]. Retrieved from https://www.discoverycircle.org.au/wp-content/uploads/2015/09/AMLR-Goanna-Factsheet.pdf
NSW Government, Office of Environment and Heritage (2017, September 5th). Rosenberg’s Goanna – profile. [Online], Retrieved from http://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=10826
Pelican Lagoon Research & Wildlife Centre. Rosenberg Goanna. [Online]. Retrieved from http://www.echidna.edu.au/rosenberg_goanna/rosenberg_goanna.html
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