A drenched penguin waddling in bone-chilling air seems like a recipe for frozen feathers. Yet tiny grooves and an oily sheath on the feathers prevent some penguins from becoming popsicles, according to a detailed analysis of penguin plumage reported November 22 at the American Physical Society Division of Fluid Dynamics meeting in Boston.
UCLA mechanical aerospace engineer Pirouz Kavehpour and colleagues observed gentoo penguin feathers under a scanning electron microscope and spotted a jagged surface full of nano-sized pores.
The subtle roughness forces water droplets to slide off rather than stay and freeze. Preen oil released from a gland near the base of the tail also works as a water repellent. The Magellanic penguin, which lives in warmer climates than the gentoo, has no pores on its feathers and secretes a less-potent oil, the researchers say.
Kavehpour hopes to exploit the birds’ deicing ways to design airplane wings that resist icing.
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