What do you think of this fact?
The platypus looks like someone built a new animal out of spare parts. It has a bill like a duck, lays eggs even though it’s a mammal, and the males have a venomous spur. In 2020, one more item joined the list: it glows.
A lucky find in a museum
The story starts with flying squirrels. In 2019, a team led by Paula Anich of Northland College in the US had shown that their belly fur shines pink under UV light. While examining flying squirrel pelts at the Field Museum in Chicago, the researchers pointed the UV lamp at a platypus out of pure curiosity. According to National Geographic, the result was clear: the fur glowed blue-green.
The team then checked three museum specimens, two in Chicago and one at the University of Nebraska State Museum. All three glowed. The study was published in 2020 in the journal Mammalia.
What’s actually going on
The effect is called biofluorescence. The fur absorbs light of one color and gives off light of another. According to Smithsonian Magazine, platypus fur absorbed UV light with wavelengths between 200 and 400 nanometers and emitted light between 500 and 600 nanometers. That is visible light, which is why we can see the glow.
Nobody knows yet what it’s for. Because males and females glowed equally, the researchers doubt it plays a role in mating. Maybe it helps these nocturnal animals see each other, or hides them from predators. The team itself says only field observations can settle it.
Bonus fact: According to Smithsonian Magazine, before this discovery the only mammals known to fluoresce were American opossums, followed by the flying squirrels.
What we might be missing
The most exciting question is a different one. Humans are awake during the day, while many animals are active at night and at dusk. The study suggests we may be missing entire channels of animal communication, simply because we aren’t looking in the right light.
So the strangest mammal on Earth was hiding one more card in its fur.