The Panamanian golden frog is a rare species of toad which is endemic to Panama. The species belongs to the genus Atelopus. Panamanian golden frogs inhabit the streams along the mountainous slopes of the Cordilleran cloud forests of western-central Panama. The IUCN lists it as critically endangered. Individuals have been collected for breeding in captivity in a bid to preserve the species.
Despite its common name, the Panamanian golden frog is a true toad. It was previously considered a subspecies of Atelopus varius but is now classified as a separate species.
The skin colour of the golden frogs ranges from light yellow-green to bright gold, with some individuals exhibiting black spots on their back and legs. Female golden frogs are generally larger than males; females typically range from 45 millimetres (1.8 in) to 63 millimetres (2.5 in) in length and 4 grams (0.14 oz) 15 grams (0.53 oz) in weight, with males between 35 millimetres (1.4 in) and 48 millimetres (1.9 in) in length and 3 grams (0.11 oz) and 12 grams (0.42 oz) in weight.
Like some other frogs and toads, the golden frog is capable of secreting poison to help protect itself from predators. In the case of the golden frog, this is a water-soluble neurotoxin called zetekitoxin.
The skin of A. zeteki is highly toxic, containing around 500 mouse units of toxin. A mouse unit of toxin is defined at the amount of toxin it takes to kill a 20 gram mouse. The toxin is different from the toxin in other poisonous amphibians which is evident in its extremely high toxicity which differentiates it from both toxins from Dendrobates pumilio. Due to the danger of testing the poison in human it has been done on mice. With large doses of the poison death can occur in as little as 2 minutes and with smaller doses it can be delayed for 20 or 30 minutes. Death is preceded by clonic convulsions until the functions of the circulatory and respiratory systems cease.
The life span of the golden frog is 12 years. This toad is unusual in that it communicates by a form of semaphore, waving at rivals and prospective mates, in addition to the sounds more usual among frogs. This adaptation is thought to have evolved in the golden frog because of the noise of the fast-moving streams which formed its natural habitat. The male tends to stay near the streams where breeding occurs, while in the non-breeding season the female retreats into the forests. The male uses a soft call to entice prospective mates, then grabs the female and hangs on when she crosses his path. If she is receptive, she will tolerate amplexus; if not she will attempt to buck him off by arching her spine. Amplexus can last from a few days to a couple of months, with ovipositioning usually taking place in a shallow stream.
The species was filmed for the last time in the wild in 2007 by the BBC Natural History Unit for the series Life in Cold Blood by David Attenborough. The remaining few specimens were taken into captivity and the location of filming was kept secret to protect them from potential poachers.
Populations of amphibians, including the golden frog, suffered major declines possibly due to the fungal infection chytridiomycosis. The infection is caused by an invasive fungal pathogen that reached El Valle, the home of the Panamanian golden frog in 2006. Additional factors, such as habitat loss and pollution, may have also played a role.
Although captive populations seem to thrive well, reintroducing them to an area will not stop the threat of chytridiomycosis. There are no current remedies to prevent, or any ways to control, the disease in the wild, but efforts are being made. There was one attempt to prevent a wide variety of frogs from the disease, by using bacteria known as Janthinobacterium lividium that produces a chemical against the infections; however the skin of the Gold frogs was unsuitable for the bacterium used. The San Deigo zoo started a conservation effort and received their first frogs in 2003. Since then, they have been able to successfully breed 500 individuals in captivity but will not release then into the wild until the fungal disease is less of a threat. The San Deigo zoo also sends money to Panama to keep up the conservation effort in the frogs’ native country.
The temperature at which these amphibians keep may be in correlation with the infection of chytridiomycosis . It can be seen that the fungus is more prevalent in colder conditions. If there is a cold period, the behavior and immunity of the frogs may change around the same time more spores are released. When these frogs are infected with the fungus, their body temperatures rise to fight off the fungus. However, even if the infection leaves the frog and body temperature returns to previous normal levels, the infection can reemerge.
Not only do these frogs face the threat of the fungal disease but they also are threatened by the development of society. As trees are cleared for housing and urbanization, the habitat of A. zeteki is destroyed. Other threats include the encroachment agriculture, pollution, pet trade, and aquaculture.
“Project Golden Frog” is a conservation project involving scientific, educational, and zoological institutions in the Republic of Panama and the United States. The intended outcomes of this project include greater understanding of the golden frog, coordinated conservation effort by governmental agencies and non-governmental organizations, heightened awareness of current global amphibian declines, greater respect for wildlife among Panamanians and global citizens, and greater land preservation for threatened and endangered species throughout the world. This organization will use education, field studies, producing offspring through the already captive toads, and offering financial support to help preserve these toads.
There have been two significant efforts to save these frogs. One being Amphibian Recovery Conservation Coalition (ARCC)which started in 2004. The organization exported the endangered amphibians to the USA believing it was a better environment for the endangered species. In 2005, the Houston Zoo established the El Valle Amphibian Conservation Center (EVACC) in Panama so that the endangered frogs could have protected facilities in their native country. EVACC has become a tourist attraction and the populations of the housed species are watched closely by researchers.