There are 26 recognised species of goanna or monitor lizards in Australia. The Rosenberg's (Varanus rosenbergi) is the only goanna on Kangaroo Island. The species was once common over a large portion of southern Australian, but their numbers have declined so drastically that Rosenberg's are now listed as vulnerable to threatened across their mainland range. Kangaroo Island is their last stronghold and only place where long term research has been conducted. Kangaroo Island is the last stronghold for this species.
Here are some quick facts about the Rosenberg’s goanna, they:
- are found in heath, open forest, sand dunes, coastal areas and woodland
- individually they require large areas of habitat
- are not sexually mature until 6-9 years of age
- utilise termite mounds for nesting purposes, laying up to 14 eggs
- are KI’s largest native predator, feeding on roadkill, birds, eggs, small mammals, many invertebrates and other reptiles
- can live at least 30 years
- are generally very curious.
Natural Resources Kangaroo Island, together with the community, are aiming to maintain and enhance the state of valuable natural resources in the region. Studies of Rosenberg’s goanna began on the island in 1966 and are maintained today under the direction of Dr Brian Green and Dr Peggy Rismiller. Green and Rismiller are continuing investigations into the changing goanna population and drawing information about their general ecology.
Male Rosenberg’s have been tracked moving over areas of up to 15 square kilometres. Females tend to travel less due to the large energy investment associated with breeding and egg development – digging an incubation chamber can take more than two days and eggs are guarded for another fortnight before normal activities are resumed.
More than 1000 hatchlings have been given lifetime identification tags but only 89 marked hatchlings have been recovered in the study area in the past 10 years. Juvenile survival rates are low, with only one out of 12 surviving the first year. It has still not been established when the goannas reach sexual maturity.
Due to their attraction to carrion, the rate of Rosenberg’s goanna road deaths increase in line with the amount of traffic around the island – the summer holiday tourism season has previously seen more than 570 reported road kills.
How can you help?
Vital population statistics can be established by fresh road deaths. In 2012 the first community survey, Goanna Watch was undertaken by Green and Rismiller to record any sightings of dead or alive goannas sighted across the Island, including dates and specific locations. This survey will again be held in 2017. For more information about the Goanna Watch program email firstname.lastname@example.org.
If you come across a fresh road kill specimen, and it is safe to do so, collections can be taken to the KI Natural Resources Centre during business hours where they will be frozen and taken to Dr Peggy Rismiller at the Pelican Lagoon Research and Wildlife Centre.