This is the burglar-alarm theory of bioluminescence: by turning on its lights, an animal may create enough of a scene to draw the attention of its predator's predator, and thereby perhaps save itself. The corollary of the burglar-alarm theory is the minefield theory. It says the reason so many animals tend to hang motionless in the deep, even fish, is to avoid setting off light explosions that would expose them to their enemies - their predators or their prey. Life in the midwater, in this view, is a tense affair (though the denizens do not know it) in which everyone is waiting stealthily in the dark, moving slowly if at all, watching and waiting for someone to turn on a light and for something to happen.
~ Robert Kunzig
