North American flying squirrels have been found to shine bright pink when lit with ultraviolet light.
In what surely must be a career highlight, Dr Jon Martin of Northland College, Wisconsin, stumbled upon the bizarre effect when out looking for fluorescent lichens, mosses and plants using a UV torch in his backyard. By chance, a flying squirrel was out scavenging food from his bird feeder. When he shone a torch on it to see what was going on, the squirrel’s fur fluoresced a vibrant Cheshire Cat pink.
Puzzled by what he had seen, Martin assembled a team to investigate the effect in stuffed flying squirrels stored at the Minnesota Science Museum and the Field Museum of Natural History. All of the 100 animals they found glowed pink under UV. They also found the same effect in five live species of flying squirrel but it was not seen in non-flying red and grey squirrels.
The exact purpose of the squirrels’ glowing fur is unknown. It’s most likely to be for communication or camouflage purposes, the team say.
“They could be communicating with members of their own species by showing off their fluorescence to each other, or it might be a sort of mating display,” said team leader Allison Kohler. “The other hypothesis is that they could be using this fluorescence as an anti-predator trait to communicate with other species, avoiding predation by other species by blending in or dealing with their potentially ultraviolet-saturated environments.”