World first for endangered frogs facing extinction

Littlejohn's Tree Frogs breed within 72 hours of arrival at WILD LIFE Sydney Zoo

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SYDNEY, April 29, 2026 /PRNewswire/ -- WILD LIFE Sydney Zoo has announced a groundbreaking achievement in conservation with the success of its first-ever on-site breed for release program. Within just 72 hours of arriving at a new custom-built facility, endangered frog species Littlejohn's Tree Frogs (Litoria littlejohni) have successfully produced three clutches of eggs, a milestone never before achieved in a zoo setting.

The achievement is the result of over a year of preparation in partnership with the University of Newcastle's Centre of Conservation Science and Amphibian ICU. The Littlejohn's Tree frog is an elusive native species facing imminent extinction, with threats such climate change, extreme habitat loss and degradation, and chytrid disease - an amphibian fungus which affects many Australian frog species. The impact of these threats has led to small and isolated populations, with reduced genetic diversity and therefore decreased reproduction and survival rates of tadpoles and metamorphs. 

The species is now found in only three remaining locations in the New South Wales Sydney Basin from the Watagan State Forest to the Woronora Plateau, and only with five fragmented populations.

The zoo received a cohort of 58 frogs from the University of Newcastle's Centre for Conservation Research and Amphibian ICU, including 22 wild founder individuals and 36 sub-adults hatched at the University last winter.

Ashley Wombey, Curatorial Manager Conservation, Population and Science said: "It has been over 12 months of preparation, which has included building a purpose-built breeding facility affectionately naming our "Frogservation Lab", installing life support systems with continual testing and monitoring to provide the ideal parameters that reflect their wild habitat.  The speed at which the frogs have displayed breeding behaviours tells us they have settled very quickly and that we have provided the perfect conditions for them to flourish. Not only is their arrival exciting, it is an important step in safeguarding the future of the species.  We are very excited to partner with the University of Newcastle, as the future of conservation is through collaboration."

Dr Alex Callen from the University of Newcastle's Amphibian ICU within the Centre for Conservation Science said: "The achievement is very exciting as it is only the second time that this species has been bred in human care. This Littlejohn's tree frog breeding program focuses on improving the genetic diversity of the species as it now occurs from only three isolated regions in the world." 

By establishing this breeding colony in the heart of Sydney, the zoo is ensuring that even if wild populations continue to decline, a genetically diverse "insurance population" is ready to be returned to the wild.

While a number of tadpoles have already hatched, they are in a sensitive stage of development. The zoo team is monitoring the remaining eggs closely, with more hatchlings anticipated within the next couple of weeks.

Visitors can learn more about this exciting project and get a glimpse of the "Frogservation Lab" now at WILD LIFE Sydney Zoo.

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