In 1935, Australia introduced the cane toad to its sugar cane fields to battle beetle infestations–and the ecosystem has never been the same. The toxic toads took a liking to Australia and began spreading through the northeast, killing the native predators like crocodiles, snakes, and lizards that dined on them. A small cat-like marsupial, the quoll, was no exception. In the decades after the toads’ introduction, quoll populations in northern Australia have dipped precipitously. This year, ahead of the toads’ march into the quolls’ last stronghold, the Kimberly region, scientists have found a clever way to save the endangered marsupial: training it to detest the taste of toad so it won’t get poisoned [Los Angeles Times]. And the success of the experiment has suggested a bizarre conservation campaign.
In their research, scientists from the University of Sydney found that other predators like crocodiles and snakes can learn to avoid trouble, because one experience of snacking on a sickening poison toad is usually enough to teach them a lesson. But because the smaller quoll will die from eating a single large toad, it never learns to make that association. So the researchers decided to train the marsupials to avoid the toads using a method known as conditioned taste aversion.