Arctic Penguins: How Do They Remain Ice-Free When Diving Into Sub-Zero Waters?

Have you ever wondered how arctic penguins stay warm and ice-free when nose-diving into ice cold waters that can reach temperatures as low as negative 40 degrees Celsius? In an attempt to reveal their anti-icing secrets, researchers from the University of California, Los Angeles (UCLA), took a new look at the flightless birds and noted that they are not only equipped with specialized hemoglobin that allows them to function at low oxygen levels (as was learned in a previous study), but that they produce oil that protects their body surfaces and have tiny pores that likewise help shut out the elements. Researchers hope to use their findings to improve the design of airplane wings, flaps and rudders, which can collect ice and cause planes to crash.

"I noticed the penguins were coming out of very cold water, and sitting in very cold temperatures, and it was curious that no ice formed on their feathers," Researcher Pirouz Kavehpour, a professor in the Department of Mechanical and Aerospace Engineering at UCLA, said. He will be presenting his findings the 68th annual meeting of the American Physical Society's Division of Fluid Dynamics.

Arctic penguins, known as the Gentoo penguin (Pygoscelis papua), are widely distributed around the South Pole. The flightless birds are characterized by their bright orange-red bills and distinct white patches above each eye. The birds feed primarily on fish or crustaceans; when hunting they can remain submerged in frigid arctic waters for long periods of time and dive to great depths in pursuit of prey.   

For their study, researchers examined the feathers of penguins from San Diego's SeaWorld using scanning electron microscopy. They discovered the birds' feathers had tiny pores that essentially trap air and make the surface incredibly water-repellent. Additionally, the animals produce oil from a gland located near the base of their tail and apply it over their feathers to further seal their pores. When water meets the superhydrophobic surface, droplets form spherical beads they either roll off a penguin's back or are shaken off before they have time to freeze – even in sub-zero climates.

When comparing the feathers of an Antarctica Gentoo penguin to those of their warmer, more northerly distributed counterparts, researchers confirmed the latter penguins did not have the same small, water-repellant pores and that they produced a different type of oil.

"It's a little ironic that a bird that doesn't fly could one day help airplanes fly more safely," Kavehpour concluded in the release.

The study was recently published in the Journal of Colloid and Interface Science. 

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