Quirks & Quarks

Lizards Learn Not to Eat Toxic Toads

Scientists teach Australian Lizards encountering invasive and poisonous toads to avoid them

Scientists teach Australian Lizards encountering invasive and poisonous toads to avoid them

Australian goanna, or monitor lizard (Georgia Ward-Fear)
The invasive cane toad has decimated many native animal populations in Australia, including the monitor lizard (known locally as the goanna). In some areas, the goanna population has been reduced by 90 percent. The unsuspecting lizards eat the toad, unaware of its extreme toxicity, and the toxin kills the lizard in 10 to 30 seconds.

But a new study by Georgia Ward-Fear, an ecologist and PhD candidate at the University of Sydney, has found a new way of helping the lizards deal with cane toads. In a recent experiment, young cane toads, who do not yet carry a lethal amount of the toxin, were introduced to areas ahead of the main invasion by adult cane toads.

The lizards who consumed the juvenile toads became ill, but were not killed, and most did not make the same mistake again. When the deadly adults arrived, the lizards avoided them. Of all the lizards trained in this way, more than half survived the 18 months of the study. It is hoped this practice can be introduced on a larger scale. 

Related Links

Paper in The Royal Society Biology Letters
- University of Sydney release
- BBC story
- Phys.org story
- Smithsonian Magazine story


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