Innovative Strategies in the Fight Against Cane Toads: Protecting Freshwater Crocodiles

Grinch, Crocodiles, and the Fight Against Cane Toads

When Dr. Seuss likened the Grinch to the “tender sweetness of a seasick crocodile,” he might have unwittingly captured a fascinating reality about these reptiles. When crocodiles feel nauseous, they don’t simply regurgitate their last meal; instead, they tend to become sluggish and prefer to lounge around rather than pursue another snack.

In a groundbreaking study conducted in Australia, researchers suggest that mild nausea may actually protect crocodiles from a toxic invader. To explore this idea, ecologists set traps baited with cane toad carcasses in the natural habitats of freshwater crocodiles, where they typically hunt. However, unlike the usual lethal toads, these were treated with a nauseating chemical. The findings from this experiment, recently published in the journal Proceedings of the Royal Society B, indicate that these specially tainted toads could change the dietary habits of crocodiles in a way that ultimately preserves their lives.

Cane toads were introduced to Australia in 1935 with the noble intention of controlling pests that threatened sugar cane crops. However, like many introduced species, the toads quickly became an ecological menace themselves. These hefty amphibians, which can grow as large as a chihuahua, appear to be a delicious meal to native predators. Unfortunately, they secrete potent toxins from glands near their heads when they feel threatened, making them a dangerous target for unsuspecting hunters.

Even formidable predators like freshwater crocodiles are not immune to the deadly effects of cane toads. In regions where these toads have proliferated, crocodile populations have seen staggering declines of more than 70 percent.

Dr. Georgia Ward-Fear, a conservation ecologist at Macquarie University in Australia, notes that previous attempts to eradicate cane toads have been largely ineffective, leading to the conclusion that “cane toads are here to stay.” In response to this challenge, Dr. Ward-Fear and her team have adopted a novel strategy aimed at helping native wildlife coexist with these invasive creatures.

To deter predators from consuming the toxic toads, the researchers employ a method known as conditioned taste aversion. Dr. Ward-Fear likens this approach to a beneficial experience of food poisoning, suggesting that conservationists can effectively “train animals not to eat cane toads by providing them with nonlethal encounters with cane toad baits.” This innovative tactic represents a hopeful shift in the battle against the cane toad invasion, aiming to safeguard native wildlife while adapting to the challenges posed by introduced species.