ACTIVE CAMOUFLAGE, sometimes referred to as adaptive camouflage, a type of camouflage often used by animals and military technologies in which an entity adapts to blend in with its surroundings, effectively rendering it invisible.
Animals employ active camouflage in two ways: counter-illumination and color change. Counter-illumination in marine animals is a form of bioluminescence; animals with this ability contain photophores that produce light. This enables them to mimic the effect of light passing through water, as if they were not there. The light produced on the underside of a firefly squid, for example, dissolves the dark silhouette formed by the animal’s body when seen from below by potential predators, protecting it from being seen.
Color change allows animals to rapidly blend in with backgrounds of different patterns and colors. This ability is common among cephalopods like octopus, cuttlefish, and squid, as well as some terrestrial amphibians and reptiles, such as chameleons. Color change as a form of active camouflage is widespread among many creatures inhabiting the seabed, such as the tropical flounder, which can alter the color and pattern of its body to match the changing coloration of the ground in as little as two to eight seconds.
Active camouflage became a subject of interest to militaries worldwide during the Second World War. The Royal Canadian Navy commissioned studies of counter-illumination employing diffused lighting, and the US Army Air Force followed suit with the Yehudi-lights project, developing a lighting prototype that raised the average brightness of military aircraft to match the brightness of the sky.
Active camouflage can be interpreted in diverse ways to fit a variety of technologies for military purposes. In 2011, for example, BAE Systems—a London-based multinational company and the largest defense contractor in Europe—began developing its infrared stealth technology, Adaptiv, in which the sides of an object—such as an armored vehicle, tank, or personnel carrier—are fitted with Peltier-plate panels that act as a “thermal TV screen” by being heated and cooled to match the temperature of the object’s background. This effectively renders the object undetectable to infrared technology.
In science fiction, active-camouflage technology has often featured prominently in popular franchises such as Star Trek, Predator, Halo, and the James Bond films. Meanwhile, the cloak of invisibility has been a popular motif in folklore, mythology, and fairy tales for centuries.