Its fur glows “a soft greenish blue” under a UV lamp:
The recent discovery has not been found in any other monotreme species, and it has scientists wondering: Have we been overlooking an ancient world of fluorescent fur?
“Biofluorescence has now been observed in placental New World flying squirrels, marsupial New World opossums, and the monotreme platypus of Australia and Tasmania,” the authors write.
“These taxa, inhabiting three continents and a diverse array of ecosystems, represent the major lineages of Mammalia.”Carly Cassella, “The Mystery of The Platypus Deepens With The Discovery of Its Biofluorescent Fur” at ScienceAlert
The platypus has other unusual features for a mammal, of course:
It’s not enough to be a mammal who lays eggs, sports a duck-like bill and webbed feet, hunts using electroreception, and wields venomous spurs. The platypus also glows green under ultraviolet light.
The finding is also interesting from an evolutionary perspective … Monotremes, marsupials, and placental mammals (eutherians) split off from a common ancestor some 150 million years ago … That’s a lot of time and lot of possible evolution.”George Dvorsky, “As If the Platypus Couldn’t Get Any Weirder” at Gizmodo
Dvorsky also tells us at Gizmodo that “fungi, fish, phytoplankton, reptiles, amphibians, and at least one species of tardigrade” have either biofluorescence or bioluminescence as well. One wonders how exactly the individual species of tardigrade (water bear) began to do that. What was the time frame there?