This intriguing science mystery by a debut Wisconsin author begins in the Northwoods, on a night ecologist Jonathan Martin was studying tree frogs in his backyard. Using his ultraviolet flashlight, he saw something pink and luminous flash through the upper canopy. He couldn’t believe his eyes: It was a flying squirrel. Specifically, a GLOWING flying squirrel. Nothing like it had ever been documented. The surprise discovery led to the formation of a small team of scientists at Northland College in Ashland. Was this phenomenon unique? Tied to a specific family of squirrels or certain species? Was the fur glowing from exposure to something, or did it glow naturally? Were there other animals that glowed? “Team Biofluorescent,” as they called themselves, began researching the scientific record to find out what else was known about biofluorescence in animals. There were many examples of jellyfish, coral, and sea anemones, and some land animals like tree frogs and chameleons, but only one record of a mammal, and nothing about flying squirrels. They narrowed their search by looking at other specimens at the Field Museum in Chicago, discovering even more surprises in the dark. Their exciting scientific discovery from 2019 is told here in an engaging account that includes explanation of scientific terms, and captivating photographs. (Ages 8-13)