Mystery of Glowing Bats: Why Do Certain Species Shine Under UV Light? | CNN

Researchers in Georgia have made an interesting discovery: some North American bats glow under UV light. This isn’t just a Halloween trick; it’s a real feature of these animals.

Using ultraviolet lighting, scientists found that six different species of bats emitted a green glow. This is the first time such luminescence has been recorded in bats from this geographical area. The findings, announced by the University of Georgia, add to a growing list of mammals known to glow. But the reason why some mammals show this glow while others do not remains a mystery.

“We already knew many mammals have this glow. The big question is: why?” said Steven Castleberry, a wildlife ecology professor involved in the study. He explains that understanding this glowing feature can help with conservation and management of bat populations.

Briana Roberson, a lead author of the study, was inspired to research glowing mammals after reading about others that share this trait. A significant paper from 2019 discovered that flying squirrels also fluoresce under UV light, sparking interest in what other creatures might do the same.

In a recent study published in 2023, researchers identified 125 mammal species that glow under UV rays. Additionally, studies from around the world have focused on other bat species, including one that found the toes of the Mexican free-tailed bat glow as well. This broad interest highlights a fascinating trend among mammals.

Roberson focused her research on six bat species, including big brown and eastern red bats. During her research, she used UV light on dozens of specimens, observing that all emitted a green glow from their wings and hind limbs.

The researchers initially proposed that the bats might use their glow for camouflage in their leafy summer roosts. However, after comparing the luminescence with that of chlorophyll used in photosynthesis, they found no match. This led them to contemplate other possibilities, like whether the glow helps bats identify one another.

Despite testing various hypotheses, the purpose of the glow is still unknown. Roberson noted, “It’s possible for glowing functions to be more diverse than we previously thought.” Castleberry added that it’s also possible the glow is a trait that once served an ecological purpose but no longer does.

Expert Kenny Travouillon, a curator at the Western Australian Museum, supports the idea that fluorescence is common among mammals. He stated that around 200 species currently show this trait, suggesting that many more could exist among the over 6,000 mammal species worldwide.

“Fluorescence is likely an inherited trait from the ancestors of modern mammals,” Travouillon explains. Understanding the purpose behind this glowing feature remains an ongoing area of research, paving the way for more questions and discoveries in the future.

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