Between the electricity-sensing invoice, venomous heel spurs and egg laying, the platypus was already one of the strangest mammals alive today (SN: 5/8/08). Now, researchers have discovered that this Australian oddity has one other sudden function: It fluoresces underneath ultraviolet mild.
Platypuses’ dense, waterproof fur absorbs ultraviolet mild and emits a blue-green glow, mammologist Paula Spaeth Anich and colleagues found considerably serendipitously. An opportunity sighting of a fluorescent flying squirrel within the wild had led the researchers to the mammal assortment on the Area Museum in Chicago. After analyzing the museum’s preserved squirrel skins and finding that fluorescence occurred in at least three flying squirrel species, the crew determined to look at pelts from marsupials too, as these had been the one mammals beforehand known to possess fluorescent fur. And it simply so occurred that the drawer of monotremes — an early department of mammals that, immediately, is represented solely by platypuses (Ornithorhynchus anatinus) and echidnas — was the following one over from marsupials.
“We had been curious,” says Anich, of Northland Faculty in Ashland, Wis. “So, we pulled the monotreme drawer, and we shined our [ultraviolet] mild on the platypuses. They usually had been extremely, vividly fluorescent inexperienced and blue.”
To ensure the glow wasn’t one thing uncommon concerning the Area Museum’s pelts, the crew additionally examined a platypus specimen on the College of Nebraska State Museum in Lincoln. Positive sufficient, it also glowed, the researchers report on-line October 15 in Mammalia.
Anich is assured that the glow isn’t an artifact of preservation, as a result of a number of of the examined squirrel species and the echidna pelts didn’t fluoresce. It’s additionally probably that the residing animals glow like their pelts, she says, as that’s been the case for all different identified fluorescent mammals.
“I’m curious to know myself now,” says Josh Griffiths, a wildlife ecologist with the environmental consulting firm Cesar in Parkville, Australia, who has been working with platypuses for over a decade. “Subsequent time I’m out trapping, I’ll take a UV mild with me and check it out.”
What, if any, function this fluorescence might have stays a thriller. Anich’s hunch is that it helps camouflage the largely nocturnal platypuses from nighttime predators which have UV imaginative and prescient, since, by absorbing among the UV mild, platypuses mirror much less of it.
Griffiths isn’t satisfied. “Possibly up in northern Queensland, they get chomped by a crocodile now and again,” he says. “However primarily, they only don’t have any predators.” As a substitute, he thinks that the glow could possibly be serving to the often solitary animals spot each other or talk once they do meet up. One thing comparable is thought to occur in some nocturnal frogs (SN: 4/3/17).
Actually, all identified instances of fluorescence in mammals happen in species which can be energetic at night time or the low mild of daybreak and nightfall, so Anich thinks the glow has one thing to do with darkness. “We don’t know as a lot concerning the nocturnal world,” she notes, so it’s potential there are lots of other fluorescent mammals awaiting discovery (SN: 2/27/20).
It might even be that the ancestor of all mammals glowed this manner. To see this function in “all three of the foremost branches” of mammals — placental mammals, marsupials and monotremes — “is admittedly indicative that it’s an ancestral trait,” Anich says, and she or he’d prefer to see additional analysis discover that chance.
Evolutionary and ecological significance apart, Griffiths is worked up to see if these findings will help biologists who research these shy, elusive animals. “Platypuses are simply bloody tough to check within the wild,” he explains, so maybe fluorescence will permit researchers to detect these creatures extra reliably.
Even when not, the glowing fur definitely provides to platypuses’ repute for bizarreness. “It’s one other bizarre factor about this bizarre creature,” he says.