Magical Metamorphosis of Endangered Littlejohn's Tree Frog

This is a new generation of frogs part of nationally-significant genetic restoration & world-first rewilding program

Conservation organisation Aussie Ark is thrilled to witness over 1000 endangered Littlejohn’s Tree Frog tadpoles begin their magical metamorphosis into frogs in the Conservation Ark facility in Somersby NSW, representing the next major step in the nation’s first breeding and rewilding program for this native amphibian.

In partnership with the University of Newcastle, Aussie Ark first joined the program in December 2025, receiving 29 adult founders from the University’s Centre of Conservation Science. In a landmark effort to curb the extinction trajectory of the Littlejohn’s Tree Frog (Littoria littlejohni) and bolster generic diversity, this original cohort was a mix of captive-born and wild-sourced frogs from four otherwise fragmented wild habitats; the Blue Mountains, Dharawal, and the Watagans, and Cordeaux. Frogs were paired, and in June of this year Aussie Ark announced the world’s first crossbreeding success between some of these populations, with four females producing hundreds of eggs.

Specialised aquaria at Conservation Ark are now full of exactly 1,111 tadpoles! This incredible number is apt for a ‘first-ever’ conservation effort!

Conservation Ark Ranger Tilly Morrison has worked in the Littlejohn’s Tree Frog breeding and rewilding program since its inception and is ‘hopping with joy’ as she watches the tadpoles sprout legs and arms.

“Tadpoles take about two months to start morphing like this,” Ms Morrison said. “For a while they look kinda silly, with four legs and a tail; half fish, half frog! Once their front legs have developed they can leap out of the water within days. So we’re on high alert!”

The Conservation Ark team is busy preparing dozens of new tanks to accommodate the 1000+ future frogs, with plans for a wild release in a year’s time.

Dr Kaya Klop-Toker from the University of Newcastle’s Centre for Conservation Science said the team was thrilled about how successful the captive breeding at Aussie Ark has been.

“These animals will play a vital role in saving this species by helping us to understand the best ways we can breed animals to restore genetic diversity that has been lost due to fragmentation and disease," Dr Klop-Toker said.

This ‘genetic rescue’ of the Littlejohn’s Tree Frog is hugely significant, especially considering the frog’s conservation status. In the wild, the species is only found in three fragmented locations, with one of its last strongholds in the Watagans in NSW. Sadly, this breeding area has been earmarked for the development of EnergyCo’s Hunter Transmission Station which will obliterate the habitat. Aussie Ark fought for many months to stop this project but was unsuccessful.

The organisation continues to work with the University of Newcastle to identify alternative release sites and offer a future for this precious cohort of new frogs.

This holistic breeding and rewilding program – from rescue to rehabilitation to ultimate release – is complex and expensive. Please help Aussie Ark save the Littlejohn’s Tree Frog from extinction by donating now at aussieark.org.au