Scientists revealed the secret behind the incredible color changing abilities possessed by chameleons.
Researchers found the stunning color changes take place due to the active tuning of a nanocrystal lattice found in a superficial layer of dermal cells called iridophores, the Université de Genève reported. The researchers also found a deeper-dwelling layer of iridophores made up of larger, less ordered crystals that reflect infrared light. The combination of these two layers of iridophores allows the chameleons to rapidly change their colors based off their behaviors (such as for courting purposes) or environment. Other than brown, red and yellow pigments, chameleons and other reptiles also contain what is known of as structural colors.
"These colors are generated without pigments, via a physical phenomenon of optical interference. They result from interactions between certain wavelengths and nanoscopic structures, such as tiny crystals present in the skin of the reptiles," wrote Michel Milinkovitch, professor at the Department of Genetics and Evolution at UNIGE.
To discover how the chameleons switch from one color to another, the researchers employed both quantum physics and in evolutionary biology.
"We discovered that the animal changes its colors via the active tuning of a lattice of nanocrystals. When the chameleon is calm, the latter are [organized] into a dense network and reflect the blue wavelengths. In contrast, when excited, it loosens its lattice of nanocrystals, which allows the reflection of other colors, such as yellows or reds," wrote the physicist Jérémie Teyssier and the biologist Suzanne Saenko, co-first authors of the article.
In the future, the researchers hope to gain further insight into the mechanisms behind the development and geometry of the ordered nanocrystals lattice.
The findings were published in a recent edition of the journal Nature Communications.
