How and why chameleons change their color

The unexplicable ability of chameleons to change color has finally become explicable due to scientists’ researches! And this is not actually about collecting pigments under the skin like a lot of people would presuppose. The secret is in structure of their skin and light reflection.

In one research there were taken five adult male reptiles, four adult females and four young panther chameleons — the ones that could be found in Madagascar. It was determined that chameleon’s skin possesses two superimposed layers consisting of iridophore cells. These cells are characterized by pigments and reflect light.

Panther chameleon

These iridophore cells comprise crystals of nanosize which have various shape and size. By making skin relaxed or tense the structural organization of the skin upper layer changes and that is the reason why the skin becomes of another hue. The scientists revealed that when an animal is calm and its skin is in natural position, the iridophore cells tend to be very close to each other. In this position short-wave light is reflected, like blue and green. And vice versa, when an animal feels in danger its skin tightens, the distance between the cells becomes bigger and in this case long-wave rays (yellow, orange, red) are reflected from it.

This chameleon has altered its color from green to yellow, but notice that red stripes did not undergo changes, they just became more vivid.

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The deeper skin layer has a peculiarity to reflect near-IR range spectrum. The scientists claim that this layer helps an animal to reflect heat from its body and thus stay cool in hot weather.

To study iridophore cells in more details, the researches used high-resolution videos and then created numerical models which forecast light reflection in cells. Moreover, the scientists extracted some cells and put on them some solutions to make the skin change. The cells started to move, swelling or shrinking, and it was clearly visible the process of changing the color.

It is observed that adult male chameleons alter the color to adjust the body temperature in accordance with the outside climate and in situations when they perceive a rival, as well as adult female reptiles in case when they want to attract a male. Young chameleon are usually of dim color and the quantity of iridophore cells is quite low in their skin. So, the way that many people thought that chameleons turn another color to camouflage themselves is not more than a tale.

It is interesting that all the conclusions and finding researches then plan to apply while creating technologies that would neutralise light reflection.

Look how amazing chameleons are.

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Let us explore our nature together!

Sources: 1, 2, 3