Smithsonian’s National Zoo reports that Panamanian golden frog populations at El Copé, in Panama, disappeared over a few months in late 2004. The same page says no individual has been seen in the wild across the species’ historic range since 2009. A bright yellow frog that talks with its hands used to be a stream resident of the Panamanian highlands. Today it lives in zoos.
The disease behind that story is chytridiomycosis, caused by the chytrid fungus. A 2019 study in Science by an international team tied it to the decline of at least 501 amphibian species. The authors call it the greatest recorded loss of biodiversity attributable to a disease. The fungus itself has no hobbies other than spreading.
This article keeps two stories apart. First the frog: what it is, where it lived and how it behaves. Then the fungus: what the sources say it is and does. Then the place where they meet, with a clear split between what is well supported and what is still debated.
The frog: species facts
The Panamanian golden frog (Atelopus zeteki) is called a frog, but the San Diego Zoo Wildlife Alliance says its skin secretions are the most toxic in the family Bufonidae, the true toads. It is a cousin of the American toad, at least on the family tree.
| Feature | What the sources say |
|---|---|
| Range | Western-central Panama, along the slopes of the Central Cordillera (Smithsonian) |
| Habitat | Wet and dry forest streams at about 335 to 1,315 meters, or 1,100 to 4,300 feet (Smithsonian) |
| Size | Males 3.5 to 4.8 cm; females 4.5 to 6.3 cm (both zoos agree) |
| Color | Light yellowish green to bright gold, often with black blotches, though some have none (San Diego Zoo) |
| Toxins | Skin contains tetrodotoxin and zetekitoxin (Smithsonian); bright color warns predators |
| Signals | Arm waving and foot lifts; no eardrums (San Diego Zoo) |
| Eggs | 200 to 620 per clutch, attached to rocks or pebbles (San Diego Zoo) |
| Tadpoles | Hatch in about 9 days, then grow for 6 to 7 months |
This article is not a guide to handling these frogs. Their skin carries toxins, so watch them from a distance, or in photographs.
The sources disagree on one habit. The San Diego Zoo says males make whistling calls. Smithsonian’s National Zoo says males attract females with visual displays instead of calls. Both agree on the waving: males wave their arms at females, and Smithsonian adds that females may wave back.
Threats to the frog that are not the fungus matter too. Smithsonian lists habitat loss and fragmentation and over-collection for the pet trade. The San Diego Zoo says frogs were once captured for tourism and as good-luck pets. The fungus is not the only villain in this story, only the one our sources call the greatest.
The fungus: disease facts
The next facts are about chytrid, not about the golden frog.
A 2010 review in PLoS Pathogens by Rosenblum and colleagues describes how the fungus works. The infective stage is the zoospore, a swimming cell with a flagellum, a whip-like tail. It lands on frog skin, enters skin cells, grows into a rounded body, and divides to make new zoospores that are released at the surface. Infected skin thickens.
How it kills is less certain. The authors hypothesize that the fungus disrupts the skin’s control of gas, water and salts, and they say the loss of salts and a water imbalance in severely infected animals are enough to cause death. A 2019 study adds that the fungus dies when it dries out, which helps explain why wet places suffer most. It also reports that two fungal species cause the disease and that both likely originated in Asia, and that humans helped spread them.
The damage, in numbers
The 2019 Science study is the widest count we found. We read the authors’ submitted manuscript on a university repository, and the published wording may differ.
| Finding | Number |
|---|---|
| Amphibian species whose decline chytrid contributed to | At least 501, or 6.5% of described species |
| Of those, confirmed or presumed extinct in the wild | 90 (18%) |
| Of those, with abundance down by more than 90% | 124 more |
| Peak of the declines | The 1980s |
| Show signs of recovery / still declining | 12% / 39% |
The authors say three Neotropical groups, Atelopus, Craugastor and Telmatobius, account for 45% of the severe declines and extinctions. The golden frog’s genus is the first. They also say the evidence is mostly retrospective, because many species declined before the disease was discovered, and that they report the numbers conservatively.
Where the two stories meet
A 2006 PNAS paper by Lips and colleagues linked the rapid arrival of chytrid at El Copé, Panama, to mass mortality and biodiversity loss across eight frog and salamander families. That fits the golden frog’s loss at the same site, but the abstract we could read does not discuss the golden frog by name.
A 2014 lab study went further. Researchers in the PLoS ONE paper infected eight captive-bred golden frogs with a hypervirulent Panamanian strain. All eight died within about five weeks. Infection grew exponentially, and a weaker earlier exposure did not help. The authors call the species a potential acute “supershedder,” meaning infected frogs may release many fungal cells. The limits are big: eight infected frogs, one strain, one high dose, and captive conditions at 21 to 22 degrees Celsius. The paper also has small inconsistencies in its own numbers, which is why we say “about five weeks.”
A 2021 lab study tested a rescue idea. Becker and colleagues added helpful skin bacteria, one of them genetically modified. All exposed frogs still became infected, and survival did not differ among exposed groups. The authors say the added bacteria were probably too scarce to protect the frogs. Smithsonian’s National Zoo describes a breeding partnership of zoos and nonprofits, the Panamanian Golden Frog Species Survival Program, and the San Diego Zoo Wildlife Alliance says it received 20 young frogs in 2003 and has hatched almost 500. For the same fungus in Chile, see Darwin’s frog.
What is known, and what is still debated
| Question | Where the sources stand |
|---|---|
| Does chytrid kill golden frogs? | Strong support: all eight lab-exposed frogs died, and both zoos name it the greatest threat. The lab test was small |
| How does it kill? | A hypothesis about salt loss in the skin; the authors say the factors behind its virulence were not conclusively identified |
| Where did it come from? | Debated: Africa was suggested early, but the 2010 authors said the origin may not be Africa; Asia is favored in 2019 |
| Does it persist outside frogs? | 2010: conclusive evidence lacking; 2019 lists persistence in other hosts and the environment as a reason for its power |
| Why few declines in Asia, Africa, Europe and North America? | Unknown. The 2019 authors list less study, early coexistence, recent arrival or unsuitable conditions |
| Can it be stopped in the wild? | The 2019 authors say mitigation in nature remains unproven |
What this looks like in practice: a timeline
| When | What happened | Source |
|---|---|---|
| 1938 | Earliest evidence of the fungus, in African clawed frogs collected that year | 2010 review |
| 1980s | Declines tied to chytrid peak worldwide | 2019 study |
| 1998 | The fungus is discovered | 2019 study |
| 2003 | The San Diego Zoo group receives 20 young golden frogs | San Diego Zoo |
| Late 2004 | Golden frogs vanish from El Copé over a few months | Smithsonian |
| 2005 to 2009 | Smithsonian gives both 2005 and 2009 for the last wild sightings | Smithsonian |
Common mistakes and myths about chytrid
Mix-up: chytrid is a virus or a bacterium. It is a fungus.
Myth: it kills every amphibian. Lab deaths in the 2010 review ranged from 0 to 100 percent, depending on species, age and temperature. The 2019 study found few declines in Asia, Africa, Europe and North America, despite the fungus being widespread there.
Myth: it is the only threat to golden frogs. Smithsonian also names habitat loss and over-collection. In some species, the 2019 authors say, chytrid acts together with habitat loss, climate change and invasive species.
Mix-up: “extinct in the wild” means gone. Becker and colleagues say large captive populations have kept the species from going extinct.
Myth: friendly bacteria cure it. In one test, they did not.
Conservation status
The Panamanian golden frog is listed as Critically Endangered on the IUCN Red List of Threatened Species. That is the category as distributed by GBIF, the Global Biodiversity Information Facility, and we checked it on November 9, 2026. Critically Endangered means the species is judged to face an extremely high risk of extinction in the wild.
Our sources use stronger words: Smithsonian says extinct in the wild, the San Diego Zoo says believed extinct in the wild, and Becker and colleagues say thought extinct in the wild. The category we read is not “Extinct in the Wild,” which is a separate IUCN category. We did not change it, and the gap may reflect the lag in GBIF’s copy or the cautious wording of “believed.” The pressures our sources name are chytrid fungus, habitat loss and fragmentation, and over-collection. We have no confirmed population trend beyond Smithsonian’s statement that none has been seen in the wild since 2009.
Categories are reviewed and can change, and the copy GBIF distributes can trail the IUCN website by some months, which is why we print the date we checked. GBIF’s copy does not give the year of the IUCN assessment, so we do not state one.
Frequently asked questions
Is the Panamanian golden frog extinct?
Not entirely. Smithsonian's National Zoo says no individual has been seen in the wild across its historic range since 2009 and describes the species as extinct in the wild, while the San Diego Zoo Wildlife Alliance says believed extinct in the wild. Captive populations survive. The IUCN category we read is Critically Endangered.
What is chytrid fungus?
It is a fungus that infects amphibian skin and causes a disease called chytridiomycosis. A 2019 study in Science says two fungal species cause it: Batrachochytrium dendrobatidis, discovered in 1998, and B. salamandrivorans, discovered in 2013. The first is the one tied to the Panamanian golden frog.
How does chytrid kill frogs?
A 2010 review proposes that the fungus disrupts the skin's control of gas, water and salts, and says the loss of salts in severely infected frogs is enough to cause death. The authors also say the exact factors that make it deadly were not conclusively identified.
Where did chytrid fungus come from?
This is debated. A 2010 review noted early evidence in African clawed frogs collected in 1938, but said the origin might not be Africa. A 2019 study says both fungal species likely originated in Asia and that humans helped spread them. Neither source treats the question as closed.
Can golden frogs go back to the wild?
Not yet, according to the San Diego Zoo Wildlife Alliance, which says none will be reintroduced until the disease threat has lessened. Smithsonian's National Zoo says the goal is to return them once chytrid can be combated.
Sources
- Smithsonian's National Zoo and Conservation Biology Institute, Panamanian golden frog. https://nationalzoo.si.edu/animals/panamanian-golden-frog (opened )
- San Diego Zoo Wildlife Alliance, Panamanian golden frog. https://animals.sandiegozoo.org/node/134 (opened )
- Scheele et al. 2019, Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity (Science; author manuscript on UCL Discovery). https://discovery.ucl.ac.uk/id/eprint/10069937/1/Garner_Scheele-et_al-Science_2019_Amphibian%20fungal%20panzootic%20causes%20catastrophic%20and%20ongoing%20loss%20of%20biodiversity.pdf (opened )
- Rosenblum et al. 2010, The Deadly Chytrid Fungus: A Story of an Emerging Pathogen (PLoS Pathogens, via PubMed Central). https://pmc.ncbi.nlm.nih.gov/articles/PMC2813266 (opened )
- Lips et al. 2006, Emerging infectious disease and the loss of biodiversity in a Neotropical amphibian community (PNAS; abstract on James Cook University repository). https://researchonline.jcu.edu.au/1621/ (opened )
- DiRenzo et al. 2014, Fungal infection intensity and zoospore output of Atelopus zeteki, a potential acute chytrid supershedder (PLoS ONE, via PubMed Central). https://pmc.ncbi.nlm.nih.gov/articles/PMC3968150 (opened )
- Becker et al. 2021, Genetically modifying skin microbe to produce violacein and augmenting microbiome did not defend Panamanian golden frogs from disease (ISME Communications, via PubMed Central). https://pmc.ncbi.nlm.nih.gov/articles/PMC9723765 (opened )