In the lush forests of Panama, a small rocket frog called Pratt’s rocket frog (Colostethus pratti) once filled the air with its distinctive calls. Then, a deadly fungal disease called chytridiomycosis swept through, decimating amphibian populations across Central America. In places like Altos de Campana National Park, where these frogs were once common, they vanished completely.
During our acoustic monitoring research, we discovered that some C. pratti populations were bouncing back, even with the fungal pathogen still present. This suggested the frogs may have evolved resistance to the disease that nearly wiped them out. In Panama, we often find frogs that declined from the pathogen either recovering or persisting at low levels. But the fact that they declined to extinction in one national park while recovering elsewhere offered a unique opportunity: a human-assisted recovery of wild rocket frogs through translocation. In the United States, mountain yellow-legged frogs have recovered using this approach, and we hoped to replicate this success in Panama.
Twelve breeding pairs were collected from the recovering population at Bajo Bonito and brought to a quarantine facility, where they were tested for the fungus and treated preventatively. Male-female pairs then spent two weeks acclimating in mesh enclosures filled with leaf litter at the release site. Previous trials had shown that frogs released directly into new habitats dispersed rapidly and suffered higher mortality rates. This gentler approach gave them time to adjust before venturing into their new home.
The team is using acoustic monitoring technology—an array of automated recorders listening for the frogs’ loud, distinctive calls—to track the population over time. This cost-effective method will reveal whether the frogs survived and dispersed. For now, the forests of Altos de Campana have restored a missing voice to the soundscape—a small but significant victory in the fight to preserve the planet’s embattled amphibians. It’s still too early to evaluate whether the population will persist, but watch this space for updates!
Meet Jorge Guerrel manager of the Panama Amphibian Rescue and Conservation Center and Dr. Gina DellaTogna STRI research associate and executive director of the Amphibian Survival Alliance who has been leading assisted reproduction research efforts around the world.
From the humid lowlands of Mexico to the tropical forests of Colombia, one sound unites the nocturnal chorus of Latin America: the distinctive tungara frog call. These small amphibians, scientifically known as Engystomops pustulosus, create one of nature’s most recognizable and beloved soundscapes across Central and South America.
The Magic of Tungara Frog Sounds
The tungara frog call is unmistakable—a sharp “tunk” followed by a descending whine that sounds almost electronic. Males gather near temporary pools, ponds, and puddles after rainfall, creating symphonies that can be heard for miles. Their vocalizations serve a crucial purpose: attracting females during breeding season, which typically coincides with the rainy months.
Cultural Connection Across Generations
For millions of people across Latin America, tungara frog sounds represent more than just amphibian biology—they’re the soundtrack to childhood memories, rainy evenings, and the rhythm of tropical life. Grandparents in rural villages often tell stories timed to the evening chorus, while children learn to identify the approach of rain by the intensity of the frogs’ calls.
Natural History and Habitat
Tungara frogs are remarkably adaptable, thriving in both pristine rainforests and human-modified landscapes. They prefer shallow, temporary water sources for breeding, making them common around homes, farms, and urban areas. This adaptability has helped preserve their populations even as development spreads across their range.
These resilient amphibians typically measure just 2-3 centimeters long, with bumpy, warty skin that helps them blend into leaf litter during daylight hours. Their calls intensify during peak rainy season, creating the iconic soundscape that has become synonymous with tropical nights from Mexico’s Yucatan Peninsula to Colombia’s Pacific coast.
The tungara frog’s voice continues to connect communities across Latin America, proving that sometimes the smallest creatures create the most enduring memories.
The chytrid fungus disease is responsible for global amphibian population declines, such as the endangered limosa harlequin frog shown above. (Brian Gratwicke/Smithsonian’s National Zoo and Conservation Biology Institute)
Researchers may have a new tool in the fight to protect neotropical frogs from extinction, thanks to climate data. In a recently published study in the journal Diversity and Distributions, researchers from the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) and the Smithsonian Tropical Research Institute (STRI) created a high-resolution map of Panama showing how a deadly amphibian disease moved across Panama over a 13-year period. But the data also provides insight into where the disease is the most dangerous and shows regions that may be havens for reintroduced, captive-bred frogs.
Since its first scientific description in 2000, Batrachochytrium dendrobatidis (Bd), a fungus that causes the deadly amphibian chytrid disease, has devastated amphibian populations in Central and South America. Believed to have originated in Asia, chytrid has since spread to many parts of the world, and the disease is responsible for wiping out nine frog species in Panama alone.
Like other fungi, chytrid requires a cool, wet environment to thrive. In chytrid-friendly conditions, disease outbreaks can decimate frog populations. But scientists have found that the fungus cannot thrive when the temperature is too high or the air is too dry. While the disease has spread throughout mainland Panama, the team wondered if the climate parameters might create an opportunity to find pockets where chytrid was less likely to kill.
By pairing satellite data with 13 years’ worth of atmospheric modeling, researchers created an ultra-high-resolution, daily temperature and humidity map for the nation. They paired this with a second dataset of over 4,900 disease samples taken from 314 sites across Panama. The second dataset tracked the amount of fungus present on each frog, known as the fungal load, over 13 years. When overlaid, the two data sets provided a clear picture of when and where the chytrid disease was the most intense. Higher elevations consistently remained more hospitable to the fungus, but rainy seasons brought chytrid-friendly conditions to the lowlands and led to waves of outbreaks.
“By compiling the hard-earned data from many amphibian researchers, we have been able to draw an unprecedented, detailed picture of the intensity of Bd in Panama through time and space,” said Carrie Lewis, doctoral student at George Mason University’s Department of Geography and Geoinformation Science, who led the study. “My hope is that we can use this detailed information to inform conservation actions in a more refined way.”
Although chytrid disease has devastated amphibian populations, the presence of the chytrid fungus alone is not a death sentence. Recognizing this, the research team built three models: one showing fungal presence; a second at “medium intensity,” which researchers consider an indicator of a serious infection; and a third at “high intensity,” which researchers associated with significant disease outbreaks. Researchers found that by examining the weather conditions 15 days prior to sampling, they could predict the presence and intensity of the chytrid fungus.
By mapping out the path and intensity of chytrid, it became clear that the disease thrives in mountainous regions, which tend to remain cooler and more humid than lowland areas. With this knowledge, researchers may be able to identify climatic refuges—areas less suitable for the chytrid disease where frogs may have a fighting chance against the fungus.
“The ability to identify places where frogs might be able to survive chytrid is critical for two reasons,” said Brian Gratwicke, NZCBI biologist and senior author of the study. “One, it allows us to look for frogs in those areas who might have developed resistance to the fungus. Two, those same areas might be sites where we can return captive-bred frogs into the wild. Both aspects could be significant turning points in the fight against the chytrid disease.”
Since 2009, the Panama Amphibian Rescue and Conservation Project based in Gamboa, Panama, has bred 12 species of frogs, all of which are facing extinction. After years of successful breeding, there are now enough animals to begin rewilding efforts. As researchers work toward reintroduction trials for imperiled Panamanian species, these prediction models will be crucial to determining when and where trials should take place.
This collaboration between 18 coauthors was partially supported with funding from the National Science Foundation, the German Science Foundation and the Bezos Earth Fund through the Tropical Amphibian Research Initiative.
Modern zoos and aquariums around the world specialize in captive breeding endangered species, they care for living collections of animals and help safeguard against their extinction. Our own project is a partnership between the Smithsonian’s National Zoo and Conservation Biology Institute, Cheyenne Mountain Zoo, Zoo New England and the Smithsonian Tropical Research Institute. This explainer video captures some of what zoos and aquariums around the world have been doing to breed endangered species.
