“Coloration serves as a dynamic form of information.” ~ English ethologist Innes Cuthill et al
The colors of plants and animals are produced by pigments and nanostructures which reflect light is specific ways. One purpose of coloration is camouflage: conveying an illusion.
Some plants hide their tender, tasty shoots from herbivores by giving them a reddish color. Mammal herbivores cannot see red. Instead, such a shoot looks a decayed yellow: certainly not worth taking a bite of.
More dramatic are deliberately crafted displays of color by animals to achieve an effect. Over the course of a few hours, horned ghost crabs in the sea around Singapore change color to match their background. How they know to create just the right level of reflective luminance to make themselves indistinguishable from their background is a mystery.
Cephalopods have impressive control over their coloration. Some cuttlefish quickly change color and shape according to the predator they are faced with, thereby maximizing their concealment for a specific observer.
Both in look and behavior, mimic octopus perform an astonishing imitation of a predator to the predator that an octopus is trying to scare off. A mimic octopus knows what frightens its enemies. A mimic octopus also knows what its prey likes: it may imitate a potential mate to devour a deceived suitor.
“The same color pattern can be perceived differently by different receivers, and this can be exploited by organisms to resolve different challenges simultaneously.” ~ English zoologist Tim Caro et al
Some damselfish have ultraviolet (UV) face patterns which facilitate individual recognition for preserving territoriality among conspecifics, while remaining largely hidden to UV-insensitive predators. Similarly, some mantis shrimp have covert polarized patterns which are invisible to other species.
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The same question arises when considering the evolution of functional biological coloration: how could it happen? Randomness is clearly out of the question. With great diversity, different life forms exhibit colors that work in predictable ways. Specific color signaling is received in the way intended: purposeful in conveying information that achieves a desirable effect for its sender.
So often, hidden information is involved in arriving at an adaptation: some knowledge of effective interaction that inspires a particular trait. Such is the instance of plants hiding delectable shoots in plain sight. What the capacity for camouflage indicates is that there is intelligent design work being done: a force behind Nature enabling coherence for clever display. That much is obvious.
Ever since Aristotle described them, chameleons have populated legends and myths because of their oddities: long projectile tongues, independently-movable eyes, zygodactyl feet, a glacial pace, and the striking ability of some species to rapidly shift the vivid color displays of their bodies. (A zygodactyle has 2 toes of its foot in front, and 2 in back. Some birds are zygodactyl.)
Many animals can rapidly change color: to communicate, camouflage, or regulate their temperature. Only a few can actively tune the color of their skin at will. Squid are a notable example; so too chameleons.
Chameleons have 2 layers of specialized cells called iridophores. Each layer has light-reflecting nanocrystals. The deeper layer reflects a broad range of wavelengths, albeit biased toward red.
By altering the spacing between the crystals in the upper layer, cells shift from reflecting blue light to reflecting yellow or red. This creates a skin color change from green to yellow or orange.
A chameleon may quickly switch between camouflage or an ostentatious display to attract mates or expel a rival. It does so by mentally tuning specific skin cells; an astonishing feat that defies purely physiological explanation but becomes plausible when considering the mind controlling energy waves, with correspondent physical activity.