Fluorescence is a natural phenomenon where energy levels are excited and the material emits its characteristic light, red or green, or yellow or something else.
Luminescence in organisms
This phenomenon is also present in many species of animals, it is observed in corals, sea turtles, frogs, scorpions, flying squirrels, parrots, rabbits, etc. We all remember that cats’ eyes glow in the dark. , because this fluorescent light appears on them when they absorb a chemical substance, like protein, UV light emits a special light.
However, it is not known how widespread this phenomenon is among mammals, and it is not clear whether or not this fluorescence is true fluorescence for some species, and what is its biological function?
So a team from the Western Australian Museum, led by the museum’s curator of mammals, Kenny Travoylan, tried to study this phenomenon by shining ultraviolet light on the museum’s collection of preserved animals.
The team examined a subset of preserved and unprotected samples with fluorescence spectroscopy at 3 different wavelengths to assess whether a true luminescence event was present, according to the team’s study published Oct. 4 in the Journal of the Royal Society Open Science. Is this phenomenon normal or a result of the methods used to preserve the specimens?
The team also examined whether fluorescence was linked to biological traits, and looked for correlations between the type and size and lifestyle of each mammal species, in an attempt to identify the benefits of glowing under UV light.
A wide range of mammals
As the abstract of the study notes, the researchers found that fluorescence is widespread across mammalian species; They identified examples of this phenomenon among 125 species representing all 27 orders and 79 families of living mammals.
For many species, there was no evidence of a change in the optical emission spectrum from the organism when the wavelength used for excitation changed, suggesting that the ‘luminescent’ mammal was already luminescent, and the mode of preservation affected its intensity. Luminosity.
Luminescence is more common and intense among nocturnal species, and they burrow to live underground, where most of their bodies are illuminated.
Scientists are still unclear whether luminescence has a specific biological role in mammals, and it appears to be a ubiquitous property of non-pigmented fur and skin. Nocturnal species.
Half of the mammal families
As a report published on the ScienceAlert website points out, the glowing effect is not limited to platypuses and wombats, which were identified as bioluminescent species a few years ago. All species of mammals tested by the research team emit green, blue, pink or white pigment under UV light.
The inside of the fox’s pointed red ears turned bright green, and the polar bear glowed like a white shirt under the black light, as did the white stripes of the zebra and the fur of the yellow tiger. The orange leaf-nosed bat’s wings become a stark white texture, while its fur glows pink. Big Philby’s ears and tails shone as bright as diamonds.
The study showed that fluorescence is present in almost half of the mammalian families, almost all clades and all 27 orders. Luminescent areas include white and pale fur, quills, whiskers, claws, teeth, and some bare skin. The only mammal without external luminescence is the dwarf spinner dolphin; Only his teeth are luminous.
Scientists know that keratin is a protein found in nails, skin, teeth, bones, feathers, whiskers, and fingernails, and is a bioluminescent protein. But when the researchers observed fluorescence in the dyed fur, they learned that a chemical other than keratin was producing the fluorine-like effect.
Some fluorescent functions
Mammals that are most active at night, dusk, or dawn may use luminescence for mating or territory defense in low light. “Luminescence is more common and more intense among nocturnal creatures,” the team says.
The platypus closes its eyes underwater to hunt, so its glowing belly fur is unlikely to be a useful visual cue, however, it may be a form of camouflage used by many aquatic animals.
Or the platypus absorbs and reflects UV light to hide it from predators and the wavelengths of light visible to prey.
The southern marsupial mole is one of the most active mammals due to its yellow and white fur. But this species lives underground. Researchers theorize that the keratin in its fur may have been reinforced to protect against abrasive soil particles, with a side effect of fluorescence.
Despite many skeptics, there is some evidence that fluorescence is evolutionarily beneficial in some mammals.
Evidence : Conversation + Scientific alert + Websites