Giant Burrowing Frogs Hide Until Heavy Rain, So a Census Means Waiting for a Downpour

Fifty-three southern giant burrowing frogs have been released into the wild in East Gippsland, Victoria, Australia, ABC News reported on Nov. 8. They came from a Zoos Victoria breeding program that began with tadpoles rescued after the 2019–20 Black Summer fires.¹

The program started from very little. Snowline Ecology herpetologist Matt Clancy said the tadpoles were found in areas no larger than a puddle, and he described the discovery as a miracle. The fires had destroyed large areas of the species’ forest habitat.¹

“A lot of those areas were just completely burnt and reduced to no vegetation at all, which we think had quite a severe impact on some of the populations of this species,” Clancy said, as quoted by ABC News.¹

The release came almost six years after the fires. The species has fewer than five known breeding sites in Victoria.¹

A frog that is hard to find

The southern giant burrowing frog is roughly the size of a cricket ball. It lives in south-eastern Australia, from south of Kangaroo Valley in New South Wales, through Victoria, to Walhalla in central Gippsland.¹

Nobody has a full count of how many are left. The frogs are secretive and spend most of their time underground until heavy rain, which makes a census a job for people willing to wait for a downpour.¹

Related: Once Thought Extinct, a New Zealand Weevil Went From 6 to 260 in a Lab

“So they’re very elusive, quite a tricky species to work on,” Clancy said in the ABC report. He added that this makes finding one all the more rewarding.¹

Fire is not the only problem. Bushfires, drought and chytridiomycosis, an amphibian disease, have all hit wild numbers hard.¹

From rescued tadpoles to a breeding program

Specialist amphibian keepers at Melbourne Zoo and Healesville Sanctuary raised the rescued tadpoles. According to Zoos Victoria and the ABC, the keepers then bred the species in captivity for the first time last year.¹

Zoos Victoria threatened species keeper Meagan Lane spoke about the work in the ABC report.¹

“This is the first time that this species has been held in any zoo environment,” Lane said.¹

Lane said scientists have now secured the frogs’ genetics for future generations and gained valuable insight into the species.¹

Listening for frogs in the forest

Scientists will keep monitoring the released frogs, and they have set up song meters in the forest. These devices detect frog calls, which helps field teams find places where the frogs might be breeding.¹

“To know the species is going to continue and hopefully breed and persist out in those wild populations is just the best news we could ever hear as keepers,” Lane said.¹