Iridescent Mammals Are Much More Common Than We Thought

More than a dozen mammal species shimmer and glint purple and green, like precious opals. Their fur is iridescent, meaning its colour appears to change depending on the animal’s orientation relative to the viewer. The effect is similar to an oil slick’s colourful sheen, or the metallic dazzle of hummingbird feathers – and it’s more common among mammals than biologists thought.

Jessica Leigh Dobson at Ghent University in Belgium was studying colour in mammals using specimens at the Royal Museum for Central Africa, also in Belgium, when she noticed an electric blue glint on the fur of a tropical vlei rat (Otomys tropicalis).

“I immediately headed back to the office to see if it was documented anywhere, because everything I’d read up to then had been telling me [mammal] iridescence is only found in golden moles,” says Dobson. Golden moles are African burrowing mammals more closely related to aardvarks and elephants than true moles, their name derived from their tinsel-like hairs.