Spooky bat photoluminescence phenomenon baffles scientist

In a discovery that hits that little bit harder as it gets closer to Halloween, six species of bats have left scientist gobsmacked.

A US-based study has found that some bat species can glow under UV light – just in time for spooky season.

A team from the University of Georgia have tested 50 museum specimens across six species of bats: big brown bats, eastern red bats, Seminole bats, southeastern myotis, gray bats and Brazilian free-tailed bats for photoluminescence, meaning they glow under ultraviolet light.

The study found that all the bats were photoluminescent, across species, sex, and age, they all glowed the same.

The glow was always green and came from their wings, their back limbs, and the membrane between their legs.

A big brown bat on a mossy cave wall. Photo: istock

Photoluminescent bats photographed under UV light. Picture: Roberson et al., Ecology & Evolution, 2025 Picture: Briana Josephine Roberson, Santiago Perea, Daniel DeRose-Broeckert, Steven B. Castleberry.

“The data suggests that all these species of bats got it from a common ancestor,” said Steven Castleberry, a wildlife biologist at the University of Georgia.

“They didn’t come about this independently.”

The study showed that the way the different species and specimens all glowed the same ruled out a few explanations for the photoluminescence.

For example, it can’t help bats differentiate between their fellow species or another, or a potential mate from a rival.

“It may be an artefact now, since maybe glowing served a function somewhere in the evolutionary past, and it doesn’t anymore,” Castleberry added.

Examining live bats will be the next step in determining whether the glow has a behavioural function.

This is only the most-recent development in glowing bat research.

Previously, researchers from the Universidad Nacional Autonoma de Mexico and the University of Texas in Austin discovered a colourful glow coming from the bristles of hair on the toes of Mexican free-tailed bats.

This was while they were using UV-fluorescent powder to track bats.

They ruled out the theory that the source of photoluminescence had been transferred from the bat’s habitat, and also checked their co-roosting cave myotis bats.

The cave myotis also had a slight glow on its toes, although not as bright as those spotted on the Mexican free-tailed bats.

Are any other animals photoluminescent?

Bats definitely aren’t the only glowing animals, with a range of species also emitting photoluminescence.

Toes of a Mexican free-tailed bat that glow under ultraviolet light. Picture: Fernando Gual-Suárez

It occurs when light particles from part of the light spectrum are absorbed by a material (photons), and then re-emitted as another colour.

Coral and jellyfish are two marine species that glow, while scorpions and certain reptiles and birds are also photoluminescent.

Studies of museum species have shown how widespread the phenomenon is, with at least 125 mammals lighting up when exposed to ultraviolet light.

Are any Australian mammals photoluminescent?

Yes – platypuses are photoluminescent, glowing bright green when exposed to UV light.

This was discovered in 2020, but scientists haven’t yet nailed down why this is the case.

Following this discovery, Australian scientists put other native species to the test, finding that both wombats and bilbies are also photoluminescent.

Carnivorous marsupials were found to not be photoluminescent, which makes sense given one type hunts the other.

A photoluminescent prey wouldn’t be able to hide from a predator.

Originally published as Spooky bat photoluminescence phenomenon baffles scientist