The South American polka dot tree frog is adorable under any circumstances, with a pale yellow body and signature dots. However, it has a secret that has been well hidden from science until recently. This unassuming frog was found to glow blue and green under ultraviolet illumination.
According to the journal Nature:
"The ability to absorb light at short wavelengths and re-emit it at longer wavelengths is called fluorescence, and is rare in terrestrial animals. Until now, it was unheard of in amphibians. Researchers also report that the polka dot tree frog uses fluorescent molecules totally unlike those found in other animals.
Three molecules — hyloin-L1, hyloin-L2 and hyloin-G1 — in the animals’ lymph tissue, skin and glandular secretions were responsible for the green fluorescence. The molecules contain a ring structure and a chain of hydrocarbons, and are unique among known fluorescent molecules in animals. The closest similar molecules are found in plants, says study co-author Norberto Peporine Lopes, a chemist at the University of São Paulo in Brazil."
Here you can see the change when the regular lights are dimmed and an ultraviolet light is turned on:
The polka dot tree frog may not be the only frog species capable of such a glowing change of color. The researchers are eager to see if frogs with similar translucent skin also transform under UV light. With this discovery, there's a whole new way to look at frogs!