There are animals out there that glow, and a lot more of them than you might think. Indeed, you may assume that it’s only the gleaming fish, squid, and shrimp that make their own light. But many mammals glow, too, not through bioluminescence, but through photoluminescence, a distinct biological process that’s best spotted by observing animals under ultraviolet, violet, or blue light.
A team of researchers recently set out to identify the chemistry that makes some mammals glow under these wavelengths of light. Reporting their results in a study in PLOS One, the team found which photoluminescent chemical compounds, or luminophores, appear in the fur of the bandicoot — a mouse-like marsupial from Australia, as well as in the fur of five other Australian mammals.
“We wanted to find out whether the luminophores present in bandicoot fur might be common across multiple species,” said Linda Reinhold, a study author and a researcher at James Cook University, in Queensland, Australia, according to a press release.
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Photoluminescence in Australian Animals
While photoluminescent animals glow, they glow differently from bioluminescent animals, which generate light through chemical reactions. Instead, photoluminescence, which includes both biofluorescence and biophosphorescence, gives off a gleam by absorbing and emitting externally generated light, transforming it in the process from higher-energy wavelengths — like those of ultraviolet, violet, or blue light — into lower-energy ones.
Many mammals — and many Australian mammals in particular — possess photoluminescent fur, a widely accepted fact among biologists.
“Rats, along with bandicoots, possums, bats, tree-kangaroos, and many other creatures in Australia and around the world are photoluminescent; they glow under ultraviolet, violet, or blue light,” Reinhold said in the release.
But the first paper to chemically assess Australian animals’ luminophores, or the chemical compounds involved in their photoluminescence, was published only around 50 years ago, in 1971.
Setting out to learn more about the luminophores in Australia’s photoluminescent mammals, the team of researchers turned to the fur of seven separate species, including two species of bandicoot (Perameles pallescens and Isoodon macrourus), one species of quoll (Dasyurus hallucatus), one species of possum (Trichosurus johnstonii), one species of tree-kangaroo (Dendrolagus lumholtzi), and one species of rat (Rattus tunney), as well as the single species of platypus (Ornithorhynchus anatinus).
Identifying the photoluminescent luminophores present in these species’ fur, which shine in various (sometimes simultaneous) shades of pink, blue, yellow, and white, the team’s analyses showed that different luminophores were present in the fur of different animals, varying from species to species. The researchers write that the chemistry involved in the photoluminescence of Australian mammals is potentially much more complex than traditionally thought, with the results indicating the “presence of several luminophores that remain to be identified or confirmed.”
Read More: Glow-in-the-Dark Amphibians Are Way More Common Than Scientists Thought
Studying Luminophores
To study these animals’ luminophores, the team collected roadkill from Queensland, Australia, and analyzed the chemical composition of the carcasses’ fur with high-performance liquid chromatography, a technique that isolates specific chemical components from more complex mixtures.
“Protoporphyrin was present in all species in this study, but the intensity differed,” the researchers write. “It is possible that protoporphyrin is a ubiquitous compound in fur that varies in concentration in different species.”
Moreover, the team found that the pink photoluminescence in both bandicoot species, as well as in the quoll and possum, was probably tied to the presence of other porphyrin compounds in their fur, including uroporphyrin, coproporphyrin, and heptacarboxylporphyrin.
According to the study, the work is a first-of-its-kind analysis for these seven Australian species, all of which are found in the wet tropical forests of Queensland.
“This is the first study to indicate the extent of the mostly unidentified luminophore composition across species of marsupial, monotreme, and placental mammal fur from one bioregion of Australia,” the researchers write.
Read More: Birds-of-Paradise Use Biofluorescence to Attract Mates
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Sam Walters is a journalist covering archaeology, paleontology, ecology, and evolution for Discover, along with an assortment of other topics. Before joining the Discover team as an assistant editor in 2022, Sam studied journalism at Northwestern University in Evanston, Illinois.
