Since 2009, no one has seen a Panamanian golden frog in the wild. These bright yellow frogs disappeared completely when an amphibian fungal disease, chytridiomycosis, swept through Panama reaching El Valle de Anton, the last stronghold of golden frogs.
Researchers at the Smithsonian Institution predicted these declines based on the pattern of disease spread, but to get ahead of the disease, a coalition of organizations built the the Panama Amphibian Rescue and Conservation Project (PARC) with a mission to safeguard golden frogs (Atelopus zeteki) and other amphibians most at risk of extinction. After successfully breeding them in captivity, the project has begun releasing frogs to understand the science of rewilding these imperiled animals.
“We provide care for some of the most endangered amphibians in Panama, and now we are entering a new phase of our work to study the science of rewilding,” said Roberto Ibañez director of PARC.
The golden frog is endemic to Panama and was found only near fast-running streams flowing from the mountainous region of central Panama. Chytridiomycosis, the deadly fungus that infects a frog’s skin leading to death, can swim through water and hitch a ride on other wildlife, even on people’s shoes. The disease is still present in many other areas of Panama, so the release trial presents an opportunity to understand how frogs transition from human care to the wild.
Researchers released 100 golden frogs in soft-release pens, known as mesocosms, and came back to monitor them post-release. The frogs initially spent 12 weeks in the mesocosms, and about 70% of them died from chytridiomycosis. Although that number may seem stark, the data collected from the deceased frogs will be used to understand disease dynamics and how the animals regain their skin toxicity after consuming a wild diet. Many of the remaining frogs were fully released following the 12-week trial.
“These crucial data will inform our conservation strategy moving forward,” said Brian Gratwicke, conservation biologist with the Smithsonian Zoo and Conservation Biology Institute. “Our earlier modeling suggested there may be release sites we can select that will be climatic refuges — places that are suitable for the frogs but too hot for the fungus. Our observations here show that we can maintain frogs for long periods in mesocosms, and if we discover signs that they regain their skin toxins, that will be important information as we roll out our release trials to other more climatically favorable places.”
Three other species were released in 2025 under the Smithsonian’s Tropical Amphibian Research Initiative. These included crowned tree frogs (Triprion spinosus), Pratt’s rocket frogs (Colostethus pratti) and lemur leaf frogs (Agalychnis lemur). The release trials have exceeded researchers’ expectations with excellent survivorship of lemur leaf frogs, while passive acoustic monitoring indicates that the crowned tree frogs and Pratt’s rocket frogs are surviving as well.
Banner image: Panamanian golden frogs in captivity in 2006. Image by Rhett Ayers Butler/Mongabay.
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