What is bioluminescence?
Bioluminescence -- the emission of visible light by living organisms -- is a characteristic of many near-surface ocean creatures. It is in the deepest parts of the oceans, however, that bioluminescence has reached a high state of development; more than two thirds of the species there produce light. Some fishes, squids, and euphausiids (krill) possess "search lights" with lenses, reflectors, and irises almost as complex as those of the human eye.
