Recent discoveries highlighted that the fur of various mammal species glows in pretty shades of pink and red when exposed to ultraviolet (UV) light. Unravelling the cause of this unexpected phenomenon, an international collaboration lead by researchers from the Humboldt University in Berlin and the Museum für Naturkunde Berlin identified the molecule porphyrin, an organic colorant, as the source of this luminescent fur. Rather than serving an ecological function, as previously assumed, luminescent fur results from the body’s waste management of porphyrins. These findings imply that the process underlying luminescence is widespread in mammals