Feeling small and blue today? Eudyptula minor goes through its whole life that way. This Australian bird—the smallest of all penguins at around 30 cm high—sports a notable blue tint in its feathers, hence its common name, the Little Blue Penguin. Using high-powered microscopes, researchers have now discovered that nanometer-sized fibers in the bird's wing feathers provide the unusual blue hue. Made from keratin, the same material as human hair, these nanofibers are packed together like bundles of uncooked spaghetti, the team reports online today in Biology Letters. The penguin's color is due to blue light that is scattered when it hits the fibers, while all other wavelengths of light just pass through the feathers. This is a new mechanism for giving feathers a blue color, the authors say; similar nanofibers are found in the blue skin of other birds, such as Emus, but those fibers are made of collagen. What advantage the colorful feathers provide for Little Blue remains unknown, but they certainly aren't being caught dead in the same black and white tuxedo as most of their relatives.
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