Popular culture has long heralded thermal imaging as the pinnacle of surveillance technology. But now infrared cameras have found — or haven’t found — their kryptonite.

Unlike most animal fur, the pelt of a polar bear is composed of hollow hair follicles that, rather than absorb heat emanating from the animal, reflect infrared emissions back onto the polar bear’s body. These heat-trapping hollow hairs help insulate the animals in subzero arctic temperatures while inadvertently shielding the bears from infrared.

The polar bear’s immunity to technological advancement in this area has already spurred further advancement in another. Researching the animal’s fur, chemists from Zhejiang University in China were able to synthetically replicate the hair’s structure. Shrouding a bunny in a blanket made from the polar bear-inspired material, the scientists successfully tested their own infrared invisibility cloak.