The safe answer to how a lantern shark turns its luminescence on and off is: “Any way it wants.” Now researchers have looked into the belly of the beast and found that three hormones act as on-off switches for these glow-in-the-dark sharks. It is the first discovery of hormones controlling bioluminescence in animals, the scientists report in the November 15 Journal of Experimental Biology. Belgian researchers identified melatonin, prolactin and alpha-MSH, three hormones known to control sharkskin coloration, as key players in setting sharks aglow. In all animals investigated up to this…

