The Panamanian golden frog (Atelopus zeteki) is a unique and beautiful amphibian from the highlands of Panama. This yellow or orange and black “frog” is actually a type of toad that walks more than it hops. It resides in areas near fast-moving streams and rivers in the mountainous forests within the country. The International Union for Conservation of Nature (IUCN) lists the Panamanian golden frog as Critically Endangered, which is one step before becoming Extinct.
In the wild they are believed to be in such low numbers that they may no longer be able to sustain as a wild population; in fact, no one has seen a Panamanian golden frog in the wild for quite some time. Massive population decreases are believed to be caused by chytrid fungus, habitat destruction, the exotic animal trade and sedimentation of egg-laying sites in rivers and streams. Now, they exist mostly in captive zoo breeding populations.
One of these breeding populations has been housed in a bio-secure room at the Detroit Zoo’s National Amphibian Conservation Center for 16 years, and has contributed several years of offspring to the Panamanian Golden Frog Species Survival Plan (SSP). SSPs are cooperative management programs through the Association of Zoos & Aquariums (AZA) that aim to reproduce, genetically manage and possibly reintroduce endangered animals into the wild with the assistance of other wildlife management organizations. In addition to its active role in the SSP, the Detroit Zoological Society (DZS) employs several other strategies to conserve the Panamanian golden frog in the wild. At this time, there is nowhere identified in the wilds of Panama to safely release captive-bred tadpole or juvenile golden frogs to the wild.
Breeding the Panamanian golden frog in captivity involves understanding the complex conditions found in their wild habitat. They have an interesting life cycle from courtship to final metamorphosis. In the wild, males of this species will perch on rock outcroppings or on top of large leaves that overhang or are near a flowing stream or river. The males then begin to call, thrusting out the vocal sacs on their throats as they produce a low trill vocalization meant to alert females to their presence as well as warn other males to stay away. Since these animals breed and live in close proximity to the loud sound of rushing water, their low-toned vocalizations can be very difficult to hear. For this reason, golden frogs have evolved a type of sign language they can use to communicate to mates as well as rivals. These amphibians have the ability to execute a “wave” using their front legs to take the place of their hard-to-hear vocalization when conditions around the stream are noisy. This type of communication is known as semaphore behavior.
Once a pair of golden frogs has successfully mated in the wild, the female will deposit up to several thousand small round white eggs underneath a rock in a steam or river and away from direct sunlight. This is done because the white eggs lack pigment entirely and would be adversely harmed by the ultra violet (UV) radiation from the sun. This same issue has to be addressed at the Detroit Zoo. The animals are bred inside aquariums in a specially modified room just for this species. After the breeding pairs are chosen for the year, the animals are placed together in an aquarium. Prior to the onset of the “wet season,” misting cycles within the frogs’ habitat are coordinated to simulate the “dry season,” giving the frogs a sense of seasonality, which helps stimulate them to breed. If eggs are laid in the aquarium, amphibian staff must protect the eggs from the naturalistic UV lighting over the breeding tanks by wrapping black trash bags around the aquarium. This simulates total darkness, which allows the light-sensitive eggs to develop unharmed. Once eggs develop pigment, the trash bags can be removed.
Eventually, the eggs develop and a small black and yellow tadpole emerges from the egg casing. These tadpoles are very well adapted to living in fast, flowing stream environments with strong mouthparts which assist them in clinging to the rocks in turbulent water as they scrape away at algae and the microorganisms they depend on for food. At the Detroit Zoo, we reproduce the golden frog food source by smearing a wet algae mix on small plastic food plates and allowing the mixture to dry. Once the algae is dry, the plates are placed in the water and the tadpoles move over and around the plate, scraping off the food with their specialized mouthpart. After several weeks, the tadpoles metamorphose into fully formed little toadlets, which are turquoise green and black in color, a color phase that camouflages them in while living in a forest habitat. They eventually turn mostly yellow or orange and black upon reaching adulthood.
Along with the extensive breeding program, conserving the Panamanian golden frog involves reaching out to the communities where these animals live and educating the public. In 2015, I assisted the staff at a small conservation center in El Valle, Panama, called the El Valle Amphibian Conservation Center (EVACC). This center is dedicated to breeding, exhibiting and educating the public on Panama’s native amphibians. While in Panama, I assisted EVACC with their amphibian exhibits and breeding programs. The DZS is also becoming involved in developing educational materials to better educate an already sympathetic public about conserving their environment and this important amphibian. Recently, DZS Curator of Education Claire Lannoye-Hall has been appointed as the SSP Education Advisor for the Panamanian Golden Frog SSP. Within this role, the Detroit Zoo will be instrumental in developing educational programs and cultural awareness within Panama.
The Panamanian golden frog holds a special place in the Panamanian culture. Signifying good luck, the golden frog can be seen on lottery tickets and in gift shops all around the country. The history of this little amphibian within Panama can be illustrated by the presence of “rana dorada” or golden frog, in some of the petroglyphs within the country dating back to pre-European contact. Perhaps those ancient artists were hoping for a little luck as they etched images of this mystical amphibian into the rocks of the cloud forest. Hopefully, with a little of that same luck and continued dedication from the Detroit Zoological Society and its conservation partners, the Panamanian golden frog will not disappear from history for good.
– Mark Vassallo is an amphibian department zookeeper for the Detroit Zoological Society, and works in the National Amphibian Conservation Center at the Detroit Zoo.