The iridescence – a luminous phenomenon caused by different forms of refraction of light, how a rainbow on the surface – just be detected on the skin of Golden moles.
In addition to the "bright eyes" of nocturnal mammals, the discovery marks the first evidence of iridescence in mammals. And another surprise: the Golden moles are completely blind.
"They are very silky and has almost a metallic look and bright with colors ranging from blue to green," said co-author of the study, Matthew Shawkey.
Shawkey thought in studying the Golden moles after an alumna it, Holly Snyder, wrote his thesis on the iridescence. Snyder is the main author of the new study.
So it was accomplished, scientists took by four specimens of the Mole. Using highly technological equipment such as electron microspia, they analyzed the structures of hair, even the smallest elements.
And they determined that by iridescent are Yes. Then discovered that each by has a flattened format with little cuticular scale, which offers a good surface for the reflection. The scales form multiple layers of light.
Optical models suggest that these layers act as reflectors that produce the color from the interference of light. The sensitivity of this mechanism explains the variety of colors.
What remains a mystery is why blind animals have this by so captivating.
The ancestors of moles had vision, then it is possible that the iridescence is a legacy of those times. "However, these animals are already pretty far from its ancestors, then there has to be some kind of selective pressure to keep its color intact," comments Shawkey.
Another possibility is that the away predators. But Shawkey says that the brightness "would leave them more attracted", generating the reverse effect. Moles are not poisonous, so the color does not serve as a warning of danger.
The researchers actually think the iridescence is a product of the composition, since its structure allows animals a good circulation through the mud and sand.
"Many of the nanostructures that produce iridescent colors have optical properties such as stiffness and repelling water," explains Shawkey. "In the case of moles, clearly there is a communication function, then is a product of by".
The iridescence existed for at least 50 million years, since with this unique coloring beetles were discovered. An iridescent bird, with at least 40 million years ago, was also documented as well as old shells. Today some birds, snakes and fish have the phenomenon.
In the future, Shawkey and his team expect to study better the iridescence, and enter your function in moles and other species.