Happy frogs inside their sauna at Macquarie University.Credit: Anthony Waddle
“In the winter, their physiology is really depressed, and the chytrid is thriving because it’s cold. This is when you see mass die-offs of populations, and this is the critical time for us to do conservation.”
The genius of the frog saunas is their simplicity. By creating “Jenga towers” of bricks, researchers created habitats with different humidity and heat levels, allowing frogs to move between holes in the bricks and adjust to different temperatures as they go.
Inside, the humidity is as high as 100 per cent, perfect for frogs that secrete mucus from their skin (frogs don’t sweat, as such). The team leaves the greenhouse flaps open, so the frogs can leave if they choose, but they are showing no signs of wanting to leave their greenhouse saunas.
“They’re all free from chytrid, and they’re all super-fat and healthy,” Waddle said.
In May, Waddle won a prestigious Future for Nature award for his work saving amphibians from the deadly fungus.
The next step, he said, would be to get the rescued frogs breeding and then release them back into the wild in summer – complete with antibodies that would protect them against future chytrid infections.
“It’s actually the first time, to my knowledge, that someone’s done a release where we’ve attempted to mitigate chytrid in Australia,” he said.
“They’re declining in the wild because of chytrid … once it’s in the environment, it’s there forever. It’s part of the ecosystem, so you have to manage it.”
Chytrid is an invasive species and amphibian pathogen thought to originate from the Korean peninsula.
“It’s actually the worse invasive species ever … nothing else has caused as many extinctions,” Waddle said.
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“You think about things like cane toads and cats and rats … it’s worse than all of those. Just in Australia, we’ve lost six species [to chytrid], and it happened very quickly.”
Researchers have created about 70 frog saunas in Greater Sydney, and have compiled social media clips demonstrating how anyone can build a frog sauna in their backyard.
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