Post by Deleted on Nov 6, 2023 8:45:43 GMT
At night, loads of animals do something very weird – and no one knows why
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Rabbit ears, dolphin teeth and pretty much every inch of polar bears are fluorescent – in fact, 125 new species of mammal have been found to glow in the dark.
A new study has shone a light on the surprising phenomenon, and found that biofluorescence is seen in half of all mammal families.
Scientists have long known certain animals glow under UV light, such as the platypus and possums. However, with no explanation for why this occurs, it was not known to be so widespread.
Now, a team at the Western Australian Museum led by Dr Kenny Travouillon has identified dozens more dazzling species after a thorough examination of the institution’s collections.
A zebra’s white stripes, the inside of a fox’s ears and the wings of a bat all glowed a ghostly green under UV as the team showed fur, quills, whiskers, teeth, claws and skin all exhibit the strange property.
Fluorescence occurs when certain chemicals absorb non-visible light, such as UV, and emit a longer wavelength visible light back.
In the case of most mammals, the study suggests this is likely a result of molecules called fluorophores in hair and the protein tryptophan in keratin, found in skin, quills, whiskers and claws.
However, the authors needed to be sure what appeared to be fluorescence wasn’t simply the phenomenon of light scatter, which is essentially a reflection of the light source. But when changing the wavelength of the light shining on the animals, there was no corresponding change in the fluorescent light returned, confirming true fluorescence.
The authors noted fluorescence was most common in nocturnal species, but were still unable to answer the question of why animals glow in the dark.
While in some cases it may prove useful to be more visible at night, such as when looking for a mate, in many species there was little obvious explanation – such as in bats, which find each other using echolocation, or mammals that live underground.
The team also found biofluorescence was less common in flying or aquatic mammals, compared to those living above or underground, or in trees.
Biofluorescence v bioluminescence – what’s the difference?
Biofluoresence requires a direct light source – at its most basic it is essentially a reflection of light shone directly onto molecules that then re-emit the light at a different wavelength.
In bioluminescence, energy from chemicals reactions inside the organism is converted into light energy, which is emitted as a green or blue glow.
And as investigations continue into why so many animals glow in the dark, the researchers recommend future studies are carried out on living or recently deceased animals, to ensure preservation chemicals are not affecting the results.
‘Species of interest would include those with highly patterned pelts, which may be important for visual signalling or camouflage, and those with highly specialised life-histories,’ said the team, writing in the journal Royal Society Open Science.
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Rabbit ears, dolphin teeth and pretty much every inch of polar bears are fluorescent – in fact, 125 new species of mammal have been found to glow in the dark.
A new study has shone a light on the surprising phenomenon, and found that biofluorescence is seen in half of all mammal families.
Scientists have long known certain animals glow under UV light, such as the platypus and possums. However, with no explanation for why this occurs, it was not known to be so widespread.
Now, a team at the Western Australian Museum led by Dr Kenny Travouillon has identified dozens more dazzling species after a thorough examination of the institution’s collections.
A zebra’s white stripes, the inside of a fox’s ears and the wings of a bat all glowed a ghostly green under UV as the team showed fur, quills, whiskers, teeth, claws and skin all exhibit the strange property.
Fluorescence occurs when certain chemicals absorb non-visible light, such as UV, and emit a longer wavelength visible light back.
In the case of most mammals, the study suggests this is likely a result of molecules called fluorophores in hair and the protein tryptophan in keratin, found in skin, quills, whiskers and claws.
However, the authors needed to be sure what appeared to be fluorescence wasn’t simply the phenomenon of light scatter, which is essentially a reflection of the light source. But when changing the wavelength of the light shining on the animals, there was no corresponding change in the fluorescent light returned, confirming true fluorescence.
The authors noted fluorescence was most common in nocturnal species, but were still unable to answer the question of why animals glow in the dark.
While in some cases it may prove useful to be more visible at night, such as when looking for a mate, in many species there was little obvious explanation – such as in bats, which find each other using echolocation, or mammals that live underground.
The team also found biofluorescence was less common in flying or aquatic mammals, compared to those living above or underground, or in trees.
Biofluorescence v bioluminescence – what’s the difference?
Biofluoresence requires a direct light source – at its most basic it is essentially a reflection of light shone directly onto molecules that then re-emit the light at a different wavelength.
In bioluminescence, energy from chemicals reactions inside the organism is converted into light energy, which is emitted as a green or blue glow.
And as investigations continue into why so many animals glow in the dark, the researchers recommend future studies are carried out on living or recently deceased animals, to ensure preservation chemicals are not affecting the results.
‘Species of interest would include those with highly patterned pelts, which may be important for visual signalling or camouflage, and those with highly specialised life-histories,’ said the team, writing in the journal Royal Society Open Science.
Get your need-to-know latest news, feel-good stories, analysis and more by signing up to Metro's News Updates newsletter
