Flying squirrels were already exceptional, as far as rodents go. Gifted with a flap of skin between their limbs, they can glide long distances between the trees where they live. But new research suggests some of the critters hide a bizarre secret—their fur glows a brilliant, bubble-gum pink under ultraviolet light.

This makes these squirrels one of only a few mammals known to fluoresce, which is the ability to absorb light in one color, or wavelength, and emit it in another. The finding raises tantalizing questions about the function of this glowing ability and suggests that the trait may be more common than previously thought among mammals.

The discovery happened entirely by accident, says Paula Spaeth Anich, a biologist at Northland