Iridescent mammals are much more common than we thought
It has long been claimed that only one mammal – the golden mole – has fur that shimmers with rainbow colours, but it now turns out that at least a dozen more mammals have iridescent fur too
By Jake Buehler
10 September 2025
The tropical vlei rat has fur that shimmers with iridescent hues
Jessica Leigh Dobson
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 .
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“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.
Dobson searched through the scientific literature and found casual mentions of other mammal species’ shiny fur dating as far back as the 1890s. Investigating further, she and her colleagues examined the fur on specimens of mammals that were associated with anecdotal reports of iridescence – or that were closely related to species with such reports. They used a light microscope to shine light on the fur at differing angles and analysed the wavelengths – and therefore the colours – of the light reflected off the hairs.
The analysis revealed that golden moles aren’t uniquely shimmery. An additional 14 mammal species have iridescent coats, including 10 rodents and the giant otter shrew , a semiaquatic predator that is neither otter nor shrew. Six of these species had never previously been considered iridescent in the scientific literature.
