Endangered frog dads ‘give birth’ after 7,000-mile trip

Endangered male frogs with an unconventional approach to child-rearing have ‘given birth’ to 33 tiny young in the UK as part of an urgent mission to rescue the species from a devastating fungal disease.

Southern Darwin’s frog tadpoles grow up inside the vocal sacs of their fathers and are ‘born’ through their mouths as froglets.

The brooding dads made an incredible 7,000-mile journey by boat, plane, and car to London Zoo from their remote island off the southern coast of Chile.

The frogs were first discovered by Charles Darwin in 1834. Conservationists say that keeping a population in captivity will buy the species time while efforts are made to make their forest home safe again.

Amphibian chytridiomycosis is a fungal disease that has affected at least 500 amphibian species, making it one of the most devastating infectious diseases described by science.

In 2023, surveys confirmed the arrival of the deadly chytrid fungus to Southern Darwin’s frogs in the Parque Tantauco forests in southern Chile. The frogs are particularly susceptible and monitored populations declined by 90% within a year.

Last October conservationists from London Zoo located a chytrid-free population. The task was challenging – not only are the frogs tiny, they are extremely well camouflaged to blend into their mossy homes.

They travelled in specially designed, climate-controlled boxes on a long, complex route: a six-hour boat ride, a 15-hour drive to Chile’s capital Santiago, and a final flight to Heathrow.

Each fully grown male, which weighed less than 2g and measured under 3cm, continued to carry the little tadpoles until they metamorphosed into froglets.

You can watch the moment a Southern Darwin’s froglet is ‘born’ in this clip from Sir David Attenborough’s landmark nature series Life on Earth.

Ben Tapley, curator of amphibians at London Zoo, said: “This is a landmark moment in our work to protect the Darwin’s frog from the devastating impact of chytrid fungus.

“The successful parent-rearing of these froglets is a powerful symbol of hope for the species [and] highlights what can be achieved when conservationists work together.”

Andrés Valenzuela Sanchez, ZSL’s Institute of Zoology research fellow, said: “These frogs are not only vital for the future of their species but also help us better understand how we can combat chytrid fungus and safeguard other amphibians globally.”

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