A Wisconsin biologist made an unexpected discovery with an ultraviolet flashlight in hand one crisp spring night: a hot pink flying squirrel.

Jon Martin, who's also a professor at Northland College in Ashland, spotted the pink bubblegum-hued mammal in his UV beam as the creature feasted at a birdfeeder.

"I point the light at it and bam! Pink fluorescence," Martin told Newsweek.

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Shocked, Martin asked then Northland College student Allie Kohler, who now attends Texas A&M University, to help him investigate the bizarre sighting.

"[It was] seemingly unnatural in the natural world," Kohler told the magazine.

Together, the pair, along with two other colleagues, studied roughly 135 squirrel specimens and came to the conclusion that three species of flying squirrels — southern, northern and Humboldt’s flying squirrel, according to The New York Times — glimmered pink under UV light. Their extensive research on the New World flying squirrels was published last week in the Journal of Mammalogy.

"Fluorescence in varying intensities of pink was observed in females and males of all extant species across all sampled geographic areas in North and Central America and a temporal range of 130 years," the group wrote in a synopsis of their research.

It's still unclear why the creatures' naturally brown fur turns that shade of pink under UV light, though some guess it may be a way to communicate or identify their own species around dusk and dawn when they typically are the most active.

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“I think these kinds of discoveries just cause us to pause in wonder at the world around us," Erik Olson, an assistant professor at Northland who helped with the study, told Newsweek.