Chameleon CornerIt is mostly a signal
The popular story says chameleons match their background. In reality, most of the dramatic changes are about communication and body condition. Males show bright, high-contrast patterns toward rivals and females, and losing contests can turn a male dull and dark within minutes.
Temperature and light matter too. A cool chameleon often turns darker to absorb more heat, and a warm one may brighten up.
What happens in the skin
Chameleon skin has several layers of specialized cells. Some contain pigments, and deeper layers contain tiny guanine crystals arranged in a regular lattice. In 2015, researchers at the University of Geneva showed in panther chameleons that the animal changes the spacing between those crystals. Tighter spacing reflects blue light, and looser spacing shifts toward yellow and red.
The pigment cells above the crystals then filter the color, which is why green can appear when blue structure combines with a yellow pigment.
Chameleons cannot turn any color at will. Each species has its own palette, and the range is limited by the animal's genetics and its health.
Common signals
- Bright and contrasting: a confident male displaying, or a courtship attempt.
- Dark and muted: cold, stressed or unwell, and sometimes a signal to back off.
- Dark with bold spots: a female telling a male she is not receptive.
- Pale at night: many species fade to light, soft tones while they sleep.