Cane toads, introduced to Queensland in 1935, carry bufotoxins in glands behind the head that are lethal to most Australian predators. As the toad front advanced west, northern quoll populations disappeared behind it, in some areas within months of the toads' arrival.
The intervention borrows from conditioned taste aversion, a well-established learning phenomenon in which an animal that becomes ill after eating a novel food avoids it afterwards. Researchers fed captive-raised quolls small toad-meat baits dosed with thiabendazole, which causes nausea without lasting harm. Trained quolls subsequently avoided live toads, and radio-tracked releases showed better survival than untrained animals over the following weeks.
The technique is not a cure. It has been demonstrated in field trials at limited scale, teaching each animal individually is expensive, and whether learned avoidance passes reliably from mothers to young is uncertain. Toad-free offshore islands, where quolls have been translocated as insurance populations, remain a central part of the recovery effort.