Squid skin columns reflect light, changing color

Squid change skin color using winding columns of platelets in their cells that act as Bragg reflectors. These columns, made of reflectin protein, selectively transmit and reflect light, allowing rapid color changes. This discovery clarifies a long-standing mystery in cephalopod biology. The findings could inspire new materials for camouflage and adaptive fabrics, building on knowledge of structural color in other animals like butterflies and chameleons.