A tiny frog has been hiding a flashy secret. Researchers have discovered that an amphibian from the Amazon is the world’s first known fluorescent frog. Glowing an ethereal green when positioned under UV light, the scientists think that the trick may actually be fairly common among amphibians, it’s just scientists hadn’t thought to look, until now.
The frog in question, known as the polka-dot tree frog (Hypsiboas punctatus), is usually a light green color flecked with red, white, and yellow spots. It inhabits much of the Amazon basin, a common critter of the river fringes and waterways. But it was only when researchers were investigating the pigment in the amphibian’s skin that they made the surprise discovery. When they lit the creature with UV light, they found that it fluoresced. Their work is published in the Proceedings of the National Academy of Sciences.
Delving deeper into the froggies' flashy abilities, the researchers from the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires, Argentina, were able to identify three molecules in the amphibians’ lymph tissue, skin, and glandular secretions that give them their green glow.
The tiny frog in all its glowing green glory. Taboada et al. 2017
The reason behind the amphibian's glow, however, is a little harder to discern. The researchers found that it emitted an impressive amount of light, equivalent to around 18 percent of a full Moon, or 30 percent of light at twilight, which for some frogs is enough to see by. This has led the scientists to suspect it may play an important role in communication between individual amphibians.
While bioluminescence, in which creatures actively produce light through chemical processes, is fairly well documented in vertebrates, particularly fish, fluorescence in amphibians is a whole lot rarer. Fluorescence involves the ability to absorb light with short wavelengths and then re-emit it at longer wavelengths, meaning they tend to glow a green or yellow color.
Scientists have steadily been uncovering that quite a few vertebrate animals seem to display this neat trick, such as the swell shark of the eastern Pacific and even a species of turtle. Although it is thought to be much more common in the watery depths of the oceans, it’s not only limited to those living in marine environments, as it has also been discovered that some parrots have fluorescent feathers.
This latest find, however, marks the first time that an amphibian has been found to fluoresce. And the researchers suspect that the polka-dot tree frog may not be alone in this. They predict that many other species of frog that have translucent skin may have been secretly glowing without our knowledge. “I'm really hoping that other colleagues will be very interested in this phenomenon, and they will start carrying a UV flashlight to the field,” Julián Faivovich, co-author of the study, told Nature.
The frog is found across much of the Amazon rainforest. Taboada et al. 2017