Chameleons can change the color of their skin, the males anyway. We long assumed that it was a shift in pigments of some kind. Instead, researchers discovered in 2015 that chameleons possess the ability to do “active tuning of a lattice of guanine nanocrystals within a superficial thick layer of dermal iridophores”. The nanocrystals reflect a different light wavelength when they are closer together than when they are farther apart. While relaxed, the chameleon displays its plainer, native color because the crystals (inside specialized cells called iridophores) are close together. But when excited, the chameleon spreads the crystals out and displays more exciting colors.
Watercolor, ink, paint pen, and white gel pen, 6″ x 6″.