Glow-in-the-dark creatures possess one of the most amazing abilities in our world. Using only chemicals in their bodies, they can create bioluminescence, or "living light." The lights they produce come in an astonishing variety of colors and patterns. Glow-in-the-dark creatures use their light displays to hide from enemies, to cry for help, to warn of danger, or to find a mate. It is a beautiful silent language. From fireflies and glowworms to flashlight fish and velvet belly lantern sharks, the diversity and number of creatures who are bioluminescent have surprised scientists. They have found bioluminescent creatures who flit across the night sky, creep along the shadowy ground, float in moonless oceans and swim in the deepest, darkest parts of the sea.