Why do some frogs glow under ultraviolet light?

Fluorescence in frogs happens when molecules in the skin absorb short-wavelength light and emit it at a longer wavelength, making the animal appear to glow under UV or blue light. In 2017, researchers reported this effect in South American species such as Hypsiboas punctatus, showing that amphibian fluorescence is real and biologically meaningful. The exact function is still debated, but it may help with communication, camouflage, or mate recognition in dim forest environments. This is different from bioluminescence, which produces light chemically. The effect is usually invisible in normal daylight unless special lighting is used.