The South American polka dot tree frog (Hypsiboas punctatus) almost looks like a cartoon character from an animated film: friendly hues of greens, yellows and reds, polka dots on its back and the bizarre superpower of being able to glow in the dark.
According to a report from Nature, the ability to absorb light at short wavelengths and re-emit it at longer wavelengths -- called flourescence -- is a rare trait to find in terrestrial animals. No amphibian was ever found to be flourescent until now as researchers share the glow-in-the-dark properties of the polka dot tree frog in a new paper published in the journal Proceedings of the National Academy of Sciences.
At first, the researchers believed frogs might be flourescent because they have the pigment called "biliverdin", which turns amphibians' bones and tissues green. In certain insects, proteins linked to this pigment emits a red flourescence.
However, when Carlos Taboada, a herpetologist at the University of Buenos Aires, and his colleagues pointed a UVA flashlight on polka dot tree frogs near Santa Fe, Argentina, the group found that these creatures emitted an intense greenish-blue glow instead.
This green glow is because of three specific molecules in the frogs' lymph tissue, skin and glandular secretions: hyloin-L1, hyloin-L2 and hyloin-G1. They're very unique among flourescent molecules in animals, with their closest counterparts found in plants, according to co-author Norberto Peporine Lopes who is a chemist at the University of São Paulo in Brazil.
With these molecules, the polka dot tree frogs are able to give off a shockingly generous amount of light, around 18 percent as much visible light as a full Moon. For now, very little is known about this species of frog's visual system, so it's unknown if they can detect or see their own flourescence.
Co-author Julián Faivovich, a herpetologist from the University of Buenos Aires, is interested in studying the other 250 tree frog species with translucent skin to see if they are flourescent too. It's a long list to go, but there are plenty of scientists to go around.
"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," he quipped.