Against the Odds: Zoo celebrates birth of new Endangered froglets, after deadly fungus rescue mission

London Zoo is celebrating 33 new precious froglets, following an urgent mission to rescue their species from the brink of extinction. 

The birth of the young Darwin’s frogs at the world-famous conservation Zoo is being heralded as a huge milestone by conservationists leading the international project to save the species from being wiped out – a threat they face thanks to the introduction of the deadly chytrid fungus to their native habitat. 

The tiny frogs, which are particularly susceptible to the fungus, needed a refuge, while conservationists figure out how to make their forest home safe once more. 

The urgent rescue mission, which saw conservationists embark on a 7000-mile expedition in October 2024 to a remote island off the coast of Chile to retrieve healthy frogs for safeguarding at London Zoo, was documented for ZSL by wildlife filmmaker Paul Glynn. The film, A Leap of Hope, has premiered on YouTube.  

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, highlights what can be achieved when conservationists work together, and serves as a critical reminder of the role of our conservation zoo. 

“We knew we were embarking on something special - the clock was ticking, and we needed to act quickly if we were going to save these frogs – and capturing this work on film has really cemented just how vital our work is.” 

Once a sanctuary for Southern Darwin’s frogs (Rhinoderma darwinii), populations of this species in the Parque Tantauco forests in southern Chile faced devastation in 2023, when surveys confirmed the arrival of the deadly chytrid fungus. This led to a catastrophic 90% decline in monitored populations within a year, due to amphibian chytridiomycosis – a disease which has now affected at least 500 amphibian species, making it the most devastating infectious disease recognised by science.  

Andres Valenzuela-Sanchez, ZSL’s Institute of Zoology research fellow, said: “By working with partners in Chile, we’re able to safeguard these frogs in their new home at London Zoo, ensuring that this unique species has a fighting chance of recovery. 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.” 

The 33 froglets were carried and brooded by 11 male frogs rescued as part of the mission. The frogs employ a unique strategy to protect and rear their tiny tadpoles – they carry them inside their vocal sacs. After travelling by boat, plane, and car to London, the fathers – each fully grown yet weighing less than 2.0g and measuring under 3cm – continued to carry the precious little tadpoles until metamorphosed into the next generation of the extraordinary species. 

A Leap of Hope, which saw filmmaker Paul Glynn trekking behind the conservation team through the cold, moss-covered forests of Tantauco Park for hours each day, shines a spotlight on the dedication and commitment of those behind the rescue – as well as the rescue team’s remarkable ability to spot a tiny green frog among a pile of leaf litter.  

Bastián Santana, from Ranita de Darwin NGO, said: “Documenting this journey and the discovery of these incredible frogs has been such a rewarding experience. The film captures not only the urgency of conservation work – acting quickly to save the world’s most vulnerable species – but it’s a crucial tool to raise awareness of threats amphibians currently face in the wild. It's a story of action and resilience that we hope will inspire others to support amphibian conservation.” 

With the rearing of these 33 froglets and more soon to follow, London Zoo hopes that its population of Southern Darwin’s frogs will grow from strength to strength, supporting reintroduction efforts in Chile, while helping scientists understand how to counter the devastating chytrid fungus.  

Tune in to watch A Leap of Hope: A huge mission to rescue a tiny frog on YouTube -