How It Works

Toxic Madagascan toads threaten the island’s native wildlife

The introduction of the common Asian toad (Duttaphrynus melanostictus) to Madagascar was accidental. It is thought that they arrived after stowing away in freight containers arriving from south-east Asia in the late 2000s. The toxic amphibians quickly established a population of over 4 million around the port city of Toamasina, and experts now fear that the foreign species could damage the already delicate ecosystems on the island.

“In Australia, the introduction of cane toads has caused profound perturbation to many ecosystems by removing key predators from local food webs with their toxins,” says Wolfgang Wüster of Bangor University in a press release. “Similar effects are likely to occur in Madagascar, where toads were never present before, as well; predators that frequently feed on toads and do not rapidly learn or evolve to avoid them are likely to become much rarer or possibly extinct.”

The new report published in Current Biology is the first genetic evidence that the majority of native predators in Madagascar are sensitive to the toad’s toxin. James Reardon, an eradication expert with New Zealand’s Department of Conservation, and co-author of the report published  June 4th has suggested that the species must be eradicated or effectively contained to reduce further damage to the population. “If the toads become established in the Pangalanes canal system — one of the longest manmade canals in the world — eradication will no longer be an option, and they will likely cause ecological damage similar to that of the cane toad in Australia.”

“Madagascar is a wildlife haven, containing some of the planet’s richest biodiversity, including lemurs,” said Christian Randrianantoandro of Madagasikara Voakajy, another co-author of the report. “Without swift action, we expect the effects of this toad to be devastating. It could disrupt food chains and cause native predators, prey, and competitors to decline or even go extinct.”



For more information about science and technology, check out the latest copy of How It Works, available now from My Favourite Magazines and all good newsagents. If you have a tablet or smartphone, you can also download the latest digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, subscribe today!

Why are cane toads such a problem in Australia?

Top 5 Facts: Climate change

What makes some fungi so lethal?