Mating
games The cheek lights on the deep-sea loosejaw
fish may serve to locate prey in the dark, but they likely also function in
mate selection, since the organs of males are much larger than those of
females. When not in use, these lights can be rotated and pulled back into the
fish's head, sort of like the headlights on some cars. They also can be
flashed on and off. So why retract them? Probably because they have a highly
reflective layer that helps direct light outward. This shiny surface, in
contrast to the fish's velvety black body, might inadvertently reveal the
animal's whereabouts to predator or prey.
