Stealth fighters have state-of-the art technology that runs nearly $1 billion per aircraft. Harry Potter’s invisibility cloak is the stuff of fiction. Meanwhile, deep within the Arctic Circle, polar bears long ago have developed their own high-tech cloaking technology.

Polar bears are uniquely designed to hide themselves from infrared detectors. The bear’s hair has a hollow core which traps almost all of its body heat, preventing any infrared emissions from escaping the fur. This not only keeps the bear warm in its frigid habitat, it also makes it nearly invisible to an infrared camera.

Read more fun facts about animals.

Read about the $93 million camouflage blunder when an official “liked what he saw.”