1.5-minute read

As quirky creatures go, the platypus (Ornithorhynchus anatinus) is a pretty tough act to follow. The web-footed, duck-billed, paddle-tailed, venom-producing water dweller is one of only five egg-laying mammals on Earth. Although the ancient, semi-aquatic oddity has been paddling around the streams, lakes, and lagoons of eastern Australia for around 110 million years, researchers have only recently discovered another unusual platypus-ian trait—biofluorescence. Platypus fur contains special proteins that absorb sunlight and re-emit it as a blue-green glow under ultraviolet (UV) light.

Why the need for built-in brightness? Because the platypus is primarily active at night, scientists believe its biofluorescence could be an adaptation to the murky, low-light underwater world it inhabits. By absorbing rather than reflecting UV light, the fluorescent fur of the platypus may help keep it hidden from the prying eyes of predators with UV sensitive vision. Navigating in stealth mode could be especially important to the animal’s survival, given that it closes its eyes and ears underwater and can’t see or hear when trouble is headed its way.

While St. Nick’s reindeer could probably do with a break, it looks like he won’t be hitching a submersible sleigh to a team of platypuses anytime soon. Unlike Rudolph’s blinking, bright-red nose, the nocturnal animal’s blue-green fluorescence isn’t visible to the naked human eye.

You may also be interested to learn that the platypus doesn’t glow it alone. Fluorescent substances that emit light in shades of yellow, green, red, blue, and pink have also been found in the bones, fur, and skin of birds, reptiles, amphibians, and other night critters, including the flying squirrel, which glows hot pink and the water opossum, which glows purple.

Blue platypuses, pink flying squirrels, and purple opossums! We might have to spring for a UV flashlight!