Squid skin has inspired a device that can be made invisible to infrared cameras and adapted to changing conditions.

A squid’s skin contains coloured cells, some of which expand and contract to help change the animal’s appearance. To mimic this quick-change camouflage, Alon Gorodetsky and his colleagues at the University of California, Irvine, deposited dots of aluminium on a stretchy polymer. When the researchers expanded a dot, it reflected more infrared light — which is invisible to the human eye but can be felt as heat — than in its contracted state.

The team created a reflector shaped like a squid’s silhouette and placed it on a warm surface. When expanded, the device reflected more heat than its surroundings, making it visible to an infrared camera. But in its resting state, the reflector blended into the thermal background and became invisible in the infrared.

Versions of the material could be used to provide infrared camouflage and to make clothing that keeps the wearer at a comfortable temperature, the authors say.