All lit up Many animals rely on bioluminescence for more than one purpose. This blackdragon fish (Melanostomias bartonbeani), for example, has a flashlight next to each eye that it can "turn on" to look for prey or signal mates. It has a chin barbel that it can use as a lure. It has light organs arrayed along its belly that will hide its silhouette. And it has luminous bodies embedded in the gelatinous dermis and between the fin rays that serve it well during a burglar alarm display. As for so many creatures in the ocean, bioluminescence no doubt serves it well.