Far More Mammals are Fluorescent than Researchers Realized

But why it's so widespread remains a mystery

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We’ve spent a long time as a species viewing ourselves as separate from the rest of the animal kingdom. This perspective remains true in many parts of the world, especially the West, but new research challenges it. The more experts analyze, study, and experiment with animals, the more they discover we aren’t as different as we think.

Scientists have discovered, for instance, that elephants create and use names for individuals, and dolphin mothers seem to talk to their young using a form of baby talk. Similarly, fluorescence is widespread throughout nature, and now researchers discovered it’s also present in every mammalian group, including ourselves — but they can only theorize as to why.

Fluorescence

Fluorescence is common and can be found just about everywhere — from light bulbs and the cash in your pocket to over 500 minerals. Even tonic water is fluorescent. Fluorescent materials radiate visible light when exposed to the ultraviolet (UV) spectrum. But it’s also found in plants, animals, and everything in between.

Florescent organisms have atoms and molecules that absorb short-wavelength UV light (photons), which is invisible to us. This absorption increases the atom or molecule’s energy level to an excited state. When returning to their original state, they emit longer wavelengths, which we see as a colorful glow.

Research over the years has identified natural chemicals, pigments, and proteins in animals’ bones, claws, feathers, fur, skin, and teeth that emit fluorescent glows when exposed to UV lightwaves. Edward Narayan, a senior lecturer in animal science at the University of Queensland, Australia, told Newsweek:

"One example is when an animal's surface absorbs high-energy, short-wavelength UV light and emits the fluorescence as a lower-energy, colored, often pink, green or blue, glow. Fluorescence can make the previously invisible UV light visible by shifting it within the range of white light, so an animal does not necessarily have to see into the UV spectrum to detect fluorescence."

The phenomenon has been well-documented across animal species, including various amphibians, corals, fish, insects, and spiders. A 2020 study discovered that under UV light, platypuses’ bodies glow blue-green. However, scientists have documented the presence of fluorescence in only a few mammalian species. But that’s changing thanks to new research that analyzed fluorescence in over 100 mammal species.