Waving the old year goodbye

In the last blog of 2013, I want to pay homage to a special amphibian, the Panamanian golden frog ( Atelopus zeteki), a creature with a beautiful yellow and black color, as an advertisement of its poisonous nature. As it is considered to bring good luck whenever you spot one, maybe writing and you reading about it, will give some good luck to the coming year. It is also one of the few amphibians, I can’t say for sure it is the only one, that has its own national holiday; the 14th of August is known, since 2010, as National Golden Frog Day and is celebrated in honor of this very special toad. Atelopus zeteki holds a strong position in local Panamanian culture; according to myth this toad will turn into solid gold after it has deceased. In past times, local tribes would use its poison to kill other animals, just as in the case of the golden poison frog in Colombia.

David Attenborough with a Panamanian golden frog. Credit: Kieron Molloy

David Attenborough with a Panamanian golden frog. Credit: Kieron Molloy

What I love about doing research for this blog is that time after time I come across new, interesting information and remarkable facts about the species I am looking into. Every time I find out that each species has its own very unique set of behaviors and features that sets it apart from the rest. It’s like entering a new country, that leaves you amazed about how much there is left in the world to discover. And you have to love the Internet for making all that information available to us.

The Panamanian golden frog is an anuran, that has the appearance of a frog, but belongs to the harlequin toads, a group of amphibians that has been hit hard by chytridiomycosis  and climate change. In fact, the first time I saw this particular species, was in the tv-series “ Life in Cold Blood” in which Sir David Attenborough filmed the last individuals of this species in the wild. After filming, the remaining individuals were brought into captivity, because chytridiomycosis and human presence in the area posed a great threat to the survival of the species. The exact location of the capture was kept secret, because part of the reason of their decline is that they have always been collected by local people (and probably for pet trade too). Their status in local culture as a good luck charm has brought them much misfortune: a sighting of the golden frog would bring luck to someone, but I guess only seeing them at one point didn’t suffice anymore. Apart from the sad message that was conveyed in the documentary we could also witness a very distinct behavior of the toad: waving with the forelimbs and forefeet, called semaphores.

Because they live near mountainous streams, where the sound of rolling water hitting the rocks is pretty dominant, the usual vocalization used by anurans is of less use. They do make croaking sounds, but these are low-pitched and not at all as loud as the sounds that most toads and frogs make. Furthermore, they lack fully developed ears, that most tetrapods do have, with only an inner ear present and no middle-ear that normally has a critical role in transforming the sound waves. Although it was first hypothesized that these toads couldn’t hear it all, experiments now suggest that their lungs act as a kind of eardrums and that they can indeed hear and even exhibit directional hearing. But still, as an adaptation to their surroundings, they have developed more visual cues to interact with their conspecifics. The waving is the most notable one and I can imagine that it is very effective, also because of the bright coloration of these toads, that can’t be missed against the background of the rocks they live on. It also just looks very peculiar,  when an amphibian demonstrates a certain behavior that seems to be more human than toadlike.  The waving is used in different ways; to get the attention of a female in the vicinity or it becomes part of a ritualistic ‘ battle’ with a competing male. The waving is used to intimidate their opponent and to establish who is the dominant male around. Ultimately, the male that stops waving, surrenders. Griswell researched more in depth on the co-occurence of vocal and visual communication (i.e. calling and waving) in the Panamanian golden frog and his results suggest that vocalizations and semaphores indeed function together and that waving may be important in providing information on the position of males.

A waving Panamanian golden frog in the Naional Zoo in Washington DC

A waving Panamanian golden frog in the Naional Zoo in Washington DC

There still remains a lot to be discovered about these animals and hopefully the future still leaves ample room to study them in the wild. At this moment however, the species only survives in zoos; two specific projects have been dedicated to the conservation of this species, one in the US (ARCC) and one in Panama (EVACC), where conservationists try to raise awareness as well with the local people on conservation of the golden frog. Numbers in captivity are rising and high enough to reintroduce some toads to the wild, but this is not attempted yet. Chytridiomycosis is still terrorizing their habitat and establishing a new population therefore has a small chance of success. On a final note, conservation of the species is not only important because of the intrinsic value each species has, but also for us humans. The toxin that is produced only by the Panamanian golden frog, zetekitoxin, is showing promising prospects in the treatment of cancer. Another example of the great wealth that biodiversity has to offer to us.

For the footage of the BBC-documentary, see here. And The Guardian has published an interesting article as well.

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