🚀 go-pugleaf

How does a chameleon, an octopus, or a bearded dragon, change its colour?
  Is it a deliberate act by the animal, or mere skin-to-environment contact?
  Maybe it depends on purpose, as an animal which fears an approaching 
predator, seeks obscurity by becoming "invisible" (blending with 
background).
  If so, then the animal's eyes must examine the immediate environment and 
decide on the colour and hue necessary.  An instruction is then sent, via 
nerves to pigmentation cells in the skin, and the appropriate colour is 
applied - a switch in wavelength.
  Of course, the skin's pigmentation must be sufficiently flexible to 
change.
  An interesting phenomenon, and a life-preserving adaptation.