An international team of researchers has for the first time studied the mechanism of iridescence in the hairs of golden moles.
The iridescence is widespread among birds and arthropods, but in mammals it is a rare characteristic.
Grant’s golden mole, Eremitalpa granti (G. Rathbun)
In the study, published online in the journal Biology Letters, the team examines the color, morphology and optical mechanisms in hairs from four species of golden mole (Chrysochloris asiatica, Amblysomus hottentotus, Amblysomus septentrionals and Eremitalpa granti) and reveals that the iridescence in this mammal is produced in the same way as in other animal groups.
The researchers found that iridescent golden mole hairs are flattened and have highly reduced cuticular scales, providing a broad and smooth surface for light reflection.
Outer surface of the iridescent (top) and non-iridescent hair (bottom) of Chrysochloris asiatica (Matthew Shawkey et al)
“Golden moles are rare among mammals in that their hairs produce a rainbow of colors when viewed from various angles, much like the surface of a compact disc,” said Dr. Kevin Rowe, co-author on the study and Senior Curator of Mammals at Museum Victoria, Australia.
“Iridescent coloration plays a key role in attracting mates in many birds, reptiles, butterflies and beetles,” said Dr. Kevin Rowe. “The way golden moles produce iridescent coloration is similar to other animals but it has an entirely different function.”
This discovery also challenges the view that bright colors evolved in animals only to attract mates.
“The smooth surface and regular layering of hair scales – resulting in iridescence in golden moles – did not evolve for attracting mates or for camouflaging themselves from predators,” said Dr. Karen Rowe, co-author on the study and Research Associate at Museum Victoria. “It is most likely used to reduce drag and damage while the moles swim through sand and soil. The colors they produce are merely a by-product.”
