Puffin Beaks Are Fluorescent, and They’re Not the Only Ones

Scorpions, stick insects and caterpillars are among the many critters that glow under UV light

Scorpions are among the animals that fluoresce.
Under a blacklight, scorpions put on quite a show. Matt Reinbold/Flickr CC

Atlantic puffins’ beaks are distinct and colorful—a feature scientists suspect might make them more attractive to the opposite sex​. But that's not the only fun thing about puffin beaks: They also fluoresce.

As Sarah Smellie reports for CBC News, Jamie Dunning, an ornithologist affiliated with the University of Nottingham, recently discovered that Atlantic puffins' breaks light up when placed under UV light.

"It was sort of discovered by accident," Dunning tells Smellie.

As a bird expert, Dunning was aware that crested auklets, a seabird in the same family as puffins, have fluorescent beaks. So he has long wondered if their puffin relatives could also put on a show under a blacklight.

In January, Dunning placed UV light on a puffin carcass. The beak’s two yellow ridges, called the lamella and the cere, lit up.

Why Puffins have glowing beaks is another question entirely. Puffins have the ability to see UV wavelengths, which are invisible to humans. This means other puffins can likely spot the fluorescent beaks in normal daylight conditions, The Independent’s Josh Gabbatiss writes.

"It's hard to say what it would look like [to them], we can't comprehend that colour space," Dunning tells Smellie. "But almost certainly it's attractive to the birds. They must be able to see it — that's the only reason it would exist."

Puffins aren’t the only fluorescing animals. After the news of the puffin began to circulate, astrophysicist and science writer Katie Mack took to Twitter with a brief list of animals that glow under UV light.

The list includes all scorpions. Though scientists still aren’t positive why they glow, one possible reson is to help with their night vision. As Ed Yong wrote for Discover in 2011, by fluorescing, scorpions could be converting UV light from the moon and the stars into the color they can see best, blue-green. It’s believed that the glow comes from a substance in the coating of the scorpion’s exoskeleton.

Many arthropods also fluoresce thanks to the outermost layer that that produces the glow, Wired previously reported. Stick insects, millipedes and grasshoppers all light up under UV light.

Just last year, researchers discovered the first known frog to naturally fluoresce: the South American Polka-dot tree frog. Their vibrant superpower comes from three molecules that linger in their lymph tissue, skin, and glandular secretions. And although researchers aren't entirely sure why they glow, they suggest it could help with communication.

Fluorescence is certainly not limited to the animal kingdom. Many minerals also glow under UV light.

Fossilized critters can also get in on the act. As Twitter user @NadWGab notes, if organic material is replaced by the mineral apatite as the critters fossilize, they will light up under UV light.

As for the puffins, Dunning tells Smellie that something about the ridges of the beak allows UV light to be absorbed and reemitted as a glow, but it’s unclear what that something is.

As Gabbatiss reports, Dunning and colleagues in Canada have written up a paper detailing their work that they plan to published in a scientific journal. But the team still has more research to do.

Having only tested a dead puffin’s beak, they must make sure the same glowing can be found for living puffins to eliminate the possibility that the fluorescence comes from decomposition.

To protect the puffins eyes from damaging UV radiation, Dunning had sunglasses made. They now need to test puffins when they're caught for tagging. The best part of these next steps: some of the glasses are aviators.

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