Researchers have discovered the first amphibian ever with natural fluorescence: a small frog that glows bright green under ultraviolet light. It’s not common to find any critter with such a feature, but this is a first as far as frogs are concerned, making the polka dot tree frog (for now, at least) one-of-a-kind. Why the frog possesses this ability is unknown.
Things in nature that glow aren’t uncommon, but that typically comes in the form of bioluminescence, which is a light given off by creatures that is generated by the creature itself. Perhaps the most commonly encountered example is fireflies, which lets off a soft green or yellow glow. Also common is bioluminescent plankton, which typically glows blue when disturbed.
This frog, while appearing similar under ultraviolet light, is different. If you were to encounter the frog in the wild, it would look ordinary and you’d never suspect it would turn bright green/blue in the right conditions. This type of lighting effect has previously been found in certain scorpions and birds.
Why the frog — or any other animal — possesses fluorescence is unknown; it could be involved in attracting mates, in communicating with others in its species, or something else entirely. The color is at stark contrast with the researchers’ expectations; they thought it may glow red under a blacklight. The frog was found in Argentina near Santa Fe.