Noted in the journal Mammalia, "shining an ultraviolet light on a platypus makes the animal's fur fluoresce with a greenish-blue tint. They're one of the few mammals known to exhibit this trait. And we're still in the dark about why they do it — if there is a reason at all."
Other animals that have exhibited this interesting trait are scorpions, lichens, puffin beaks, and believe it or not, North American flying squirrels glow bubble pink under UV light. Blue light, just a notch away from ultraviolet, turns our oceans into what looks like an indoor mini-golf course! It's also what causes multiple types of amphibians to glow green.
Nature is lit.
Story via The New York Times