Scientists Are Teaching This Endangered Species to Stop Poisoning Itself

April 22, 2016 | Erica Tennenhouse

Northern Quoll, Dasyurus hallucatus
Photo credit: Wildlife Explorer/Wikipedia (CC BY 3.0)

Australia has its own version of a Screamapillar

But this one is not sexually attracted to fire like the critter featured on The Simpsons, about which Homer remarked: “Are you sure God doesn’t want it to be dead?”

Instead, furry quolls are hungry for poisonous cane toads—an invasive species from Central and South America that were introduced to Australia in 1935.

Their toxic skin is only part of the problem. The cane toad is also a prolific breeder, laying thousands of eggs at a time. Its population has grown to over 200 million, with no signs of slowing down. As the toads spread across northern Australia, they devastate native predator populations.

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Consuming a single cane toad can be a death sentence for a quoll. But this has not curbed their appetite for these deadly amphibians, and some quoll populations are in grave danger. Of particular concern is the northern quoll, which is already locally extinct in Kakadu National Park. If toxic toads weren’t enough, northern quolls are also under threat from feral cats.

Perhaps the quolls can be excused for continuing to poison themselves—after all, they have not had much time to evolve the ability to recognize and avoid the toads. But scientists have decided that what the quolls really need is a stern lesson.

Scientists have devised a method for teaching quolls to avoid attacking cane toads.  This involves presenting captive quolls with appetizing ‘cane toad sausage’ —a blend of skins from the least toxic cane toads and nausea-inducing chemicals. Those that invariable chow down on the treat become mildly ill, but are otherwise unharmed.

Importantly, they begin to associate the smell and taste of cane toad with nausea, and gradually learn to avoid it—this is known as ‘conditioned taste aversion.’

Quolls appear to be good students. A successful trial in 2010 showed not only did the toad-smart females survive and reproduce in the wild, but the next generation also learned to avoid eating cane toads from them.

This week, 10 ‘toad-smart’ quolls will be released into the wilds of Kakadu as part of a three-year plan to help re-establish a population there, according to a press release.

Threatened Species Commissioner Gregory Andrews said the project was part of a AUD$750,000 (USD$585,000) investment strategy to make Kakadu safe again for its native species.

“Quolls are an iconic carnivorous Australian marsupial and an incredibly important part of our ecosystem,” he said. “By teaching the quolls not to eat cane toads and making Kakadu safe for them from feral cats, we can ensure their survival in this important world heritage-listed area.”

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