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Goannas Taught the Terrible Taste of Toads

Researchers are investigating whether goannas can be taught to avoid eating cane toads at a remote site close to the cane toad invasion front in the east Kimberley.

Three of the five species of goannas found in the region are heavily impacted by toads, so researchers from the University of Sydney and the WA Department of Parks and Wildlife have joined Balanggarra Rangers to fit transponders to members of two of these species: the yellow-spotted monitor (Varanus panoptes) and the sand goanna (Varanus gouldii). Cameras have also been set up around their burrows to monitor their activities.

Once these goannas are located, they are trained in “taste aversion” by dangling a small toad from a fishing rod. The team has found that if a goanna has eaten a small non-lethal toad, they usually won’t eat another in subsequent trials. This taste aversion training could prevent goannas from eating larger toads that could kill them when the main toad front arrives, which is expected during the wet season at the end of this year.

Since entering the Kimberley region from the Northern Territory in 2009, cane toads have been advancing at around 50 km/year. The front is much more spread out than previously thought, with the faster, bigger toads evolving longer legs and moving up to 8 months in front of the main pack.