A team of Swiss researchers have discovered how chameleons manage to change their color. It seems that the reptiles rearrange the crystals that are found inside their skin cells.
The findings contradict the previous belief that the reptiles’ famous ability was possible through the gathering or dispersing of colored pigments inside the cells.
The study revealed that the reptiles have a “selective mirror” made of crystals, which reflect infrared light and also helps the chameleons keep cool
According to the scientists, chameleons have cells filled with dark colored pigment for warm conditions, while brighter shades of white and blue come from light bouncing off the crystals. The colors are also mixed by this special system that the reptiles have.
Also, it was confirmed that many reptiles and fish grow lighter or darker in this way in order to match their environment or because of stress. The new study focused on panther chameleons, which turn from their usual green to yellow when they notice a potential competitor or mate.
The team of Swiss researchers was made up by evolutionary biologists at the University of Geneva and quantum physicists. Their results were published in the journal Nature Communications.
The team noticed there were no big cells with red or yellow pigment that could explain the changes in hue, but discovered that the crystals have a major role in the color shifting using an electron microscope.
Senior author Prof Michel Milinkovitch came to the conclusion that the crystals explained not only the bright colors of the chameleon, but also the changing process, which is produced by shifting the spacing of the crystals. The scientists also compared samples of relaxed and excited chameleon skin and noticed a big change in the crystal pattern.
It is the first demonstration of this kind that was made on lizards, ”This is the first time that reptile skin has been shown to change colour thanks to this kind of geometrical shift”, Prof Milinkovitch said.
Beneath the layer of cells called iridophores that contained a regular pattern of crystals, the scientists also spotted an extra layer, where the cells were much larger and their order was irregular.
That structure reflects near-infrared light with great efficiency, but also helps the chameleon stay cool, by reflecting the warming rays of the sun.
Image Source: Lizard Types
