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Known in North America as caribou, reindeer are built to live in freezing Arctic regions like northern Norway, where this herd was photographed under the transfixing swirl of the aurora borealis, or northern lights. Reindeer have evolved unique features that help them thrive in these harsh environments. Their noses are adapted to warm the air they breathe before it enters their lungs, which helps maintain a steady body temperature even in the coldest of weather. And most of their bodies, including their hooves, are covered with thick, dense fur to keep them well insulated. In fact, they are more likely to overheat then freeze—so when they're flying through the starry skies tonight, they'll be feeling snugger than Santa Claus in his red velvet suit.
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