Think of an animal that is a master of camouflage. Did you think of a chameleon? That’s one of the biggest misconceptions about the googly-eyed lizard. The reptile changes hues as a signal in mating behavior, aggression, and territorial disputes, but not as camouflage. Chameleons won’t become checkered if you place them on a chessboard.
But other lizards do have the chameleon’s fabled ability, and a new study published this month shows that reptile camouflage can be even more amazing than we thought.
When the Moorish wall gecko settles on a dark surface, within the hour its skin will have darkened too. The lizard doesn’t exactly perform a quick-change act. You’d imagine that when the gecko does settle, its eyes register that it is on a darker surface and then there is a cascade of biological changes that alter its skin color. Biologist Domenico Fulgione thought this too…until he decided to test it.
As science journalist Ed Yong explains in his latest, Fulgione and his team blind-folded a few Moorish geckos to test the hypothesis that vision triggered the camouflage response. But even when the reptiles couldn’t see, they still changed color. It wasn’t until the team covered up the bodies of the geckos that they weren’t able to camouflage as effectively as uncovered geckos. It turned out that the geckos had light-sensitive proteins in their skin.
Opsins are light-sensitive proteins that are the ground level of light perception. You have opsins in your eyes that respond to light and set off chemical reactions, which eventually translate into electrical signals headed for the brain. “The Moorish gecko has plenty of opsins in its eyes too, but the team also found these proteins all over the skin of its torso. It’s especially common in the lizard’s flanks, and in cells called melanophores that are filled with dark pigments,” writes Yong.
If Fulgione and his team are right, then the Moorish gecko has a kind of optical camouflage that may be independent of its brain. Metal Gear Solid’s Solid Snake would be proud.
In Metal Gear Solid 4, “Old Snake” is deployed to the Middle East equipped with “OctoCamo”—a smart camouflage system that adapts color and texture in real-time (and he first uses it to hide from a Gekko!). OctoCamo also operates independently of Snake’s brain, just like the Moorish gecko’s skin. Thought-adaptive camouflage is a game-changer, and neither Snake nor the gecko is as good as the undisputed master of camouflage: the mimic octopus.