Polar Bears are invisible?

A few years ago, scientists doing an aerial census of the polar bear population in the arctic encountered a problem. The polar bears being counted were hard to spot because their white fur blended into the snow. Scientists decided to use infrared, heat sensing technology for the survey, but found that curiously, the polar bears became invisible. Scientists could see the eyes, nose and breath, but not the bear.

ME student discovers a unique fact about polar bears