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Planet Earth

Lather Up: New Sunscreen Could Be Inspired By Hippo Sweat

DiscoblogBy Rachel CernanskyMarch 17, 2009 10:47 PM


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If researchers can figure out how to replicate hippo sweat, they may bring the quest for the perfect sunscreen—and for magic tricks like sunburn indicators—to an end. A California-based research team has discovered that hippos produce an oily red secretion that contains microscopic structures that scatter light and protect the hippos from burning. The researchers, who specialize in biomimicry, hope to develop a product inspired by the sweat that will serve as a four-in-one: sunscreen, sunblock, antiseptic, and insect repellent. The team collected sweat from hippos at a zoo and found that it contained two types of liquid crystalline structures. The banded structure, characterized by concentric rings that are comparable to wavelengths of visible light, makes it effective at scattering light, and the non-banded structure reduces the sweat’s viscosity and allows it to spread more easily over the surface of the animal. The red coloring is another of nature’s impressive tricks. While at times giving hippos the appearance of bleeding, the secretion is simply akin to a form of "sweat," and is colored because of a pigment, which contains UV-absorbing molecules. Hippos may or may not mean the solution to all our problems—but it sure makes us glad we're not feeding them to the tigers. Related Content: Discoblog: You Got Burned! Wristband Warns Wearers of Impending Sunburn DISCOVER: The Biology of . . . Sunscreen

Image: Flickr / jurvetson

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