Crucifix Frogs breed thanks to YouTube clip

06 March 2020

Frogs that look like tiny green hot cross buns have been bred in captivity for the first time in the world - after an ingenious Melbourne Zoo keeper played a YouTube clip of a thunderstorm to get them in the mood.

Crucifix Frogs, which are named after the red cross-shaped marking on their backs, breed in the wild after rainstorms, when they crawl up from their underground burrows to mate in puddles.

Melbourne Zoo first started trying to get the native Australian species to spawn way back in the early 1990s.

The Zoo’s experts were aware that their best chance was during low-pressure weather systems, which the frogs recognise as a sign that rain is coming – but it took the final nudge from Ectotherms Keeper Raelene Hobbs to finally push them into action. 

“I found a ten-hour long clip of a thunderstorm on YouTube,” Mrs Hobbs said. “’It was called something like ‘epic heavy thunderstorm‘. I put it on an iPad and put the iPad in a sink opposite the frogs’ tank, which gave the sound a bit of a reverberation which we thought might help. Then I left the clip running for the whole night.”

Three clutches of eggs duly appeared, followed by tadpoles – and now Mrs Hobbs has 25 fingernail-sized baby frogs on her hands, with more tadpoles metamorphosing all the time. “They are ridiculously cute,” said the keeper. “I am elated. I still can’t quite believe it. It’s been a bit of an out-of-body experience.”

The Zoo’s five adult frogs – one male and four females – are also very engaging. About the size of 50 cent pieces, they are endearingly rotund – and have the habit of luring their insect prey by waggling their toes.

“People fall in love with them the minute they see them,” said Mrs Hobbs, who has worked with the frogs since 2011. “They look like blobs. And I suppose they have a ‘grumpy frog’ look on their faces.”

Crucifix Frogs live in semi-arid areas of New South Wales and Queensland, where they spend most of their lives burrowed up to three metres underground. They emerge after rain to mate, lay eggs and feast on termites before digging their way back into the earth. They can stay underground without eating or moving for years on end.

While the species is not at risk in the wild, keeper Mrs Hobbs said it is important to build up knowledge about how to breed them in captivity in case the frogs ever need our help in the future.

“We know how fast a species can disappear,” she said. “If there was a major drought in the areas where the frogs lived and there was no rain for 15 years, these frogs would disappear.”