Scientists in Australia are sounding alarm bells after large numbers of frogs have mysteriously died. Collie Ennis is a research associate in the Department of Zoology at Trinity College Dublin and he spoke to Cormac Ó hEadhra on RTÉ Radio 1's Drivetime about the phenomenon. (This piece includes excerpts from the conversation which have been lightly edited for length and clarity - full discussion can be heard above).

So what is going on with the frogs in Australia? "We don't know, and that's what's frightening at the moment", says Ennis. "Dr Jodi Rowley from the Australian Museum and her colleagues had set up a citizen science project for people to record frogs in their local neighborhood, because frogs in Australia are already getting hammered by a number of different factors, climate change and habitat destruction, all the usual stuff that affects wildlife.

"But in the last four or five weeks, they have been reporting mass die-offs of frogs all over Eastern Australia. From New South Wales to Victoria and Queensland, people have been finding six and seven frogs dead on their decking. They're going for jogs, they're finding them on the side of the road dead, falling out of trees. It's mainly the very quintessential Australian frog, it's the dumpy frog, the big green tree frogs, beautiful-looking creatures, look like Kermit the Frog, but they're very charming little creatures, and people are very, very fond of them around their gardens."

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From RTÉ Archives, Hall's Pictorial Weekly checks out the frog swallowing competition at the Ballycumber sports day in Co Offaly in 1973

It's the fact that all the deaths are occuring in the open which is the most concerning. "When frogs die, you never really see them out in the open. They tend to be hidden away somewhere. They're very cryptic creatures. Most of these frogs would be nocturnal. For them to be out during the day, dying on the streets, dying on patios, is highly unusual. They're also changing colors, they're lethargic, their skin is falling off, and red blisters and sores all over them. This points to something severely wrong in the population."

The theory is that a fungus is knocking the frogs for six. "There's a fungus that's wiped out populations of frogs worldwide called the chytrid fungus and perhaps that's having an effect. It's well known to be down there, and it has wiped out four species of frogs in Australia already. Perhaps with cold winter, and a combination of maybe other factors that could be causing it. They've been fighting this pandemic for decades. It's wiped out 50 species of frogs all over the world. If we find out it's that specific disease, that will be good news, but it's not a certainty."

The bad news? "The really scary thought is that another novel disease has developed in Australia", says Ennis, "and like we saw with Covid, these things tend to spread around the world. Frogs are a very key species in the food web. They eat a lot of pest species and bugs that we don't want, and they get eaten by a lot of animals that depend on them. Snakes, and mammals, and other creatures eat frogs. So they are really, really a keystone species in the food web, and a great indicator of healthy ecosystems. For them to disappear will be an absolute disaster for the environment in general, and a tragedy because they are such endearing and wonderful little creatures. So it is something that we should watch."

It's a really big mass-mortality event for amphibians, and the speed and the scale of it is terrifying

So far, Irish frogs remain in the clear, but this may change. "The Herpetological Society of Ireland conducted a survey a number of years ago, and we haven't detected chytrid fungus in Ireland. But that fungus has travelled all over the world, along with a number of other nasty bugs that have really given amphibians in general an awful beating.

"This event is very significant because it's such a large-scale event. It's a really big mass-mortality event for amphibians, and the speed and the scale of it is terrifying. We don't want to see that replicated outside of Australia. We definitely don't want that, especially given the fact that the amphibian numbers are already under pressure all over the world."