Researchers estimate that between 80 and 90 percent of deep-dwelling animals are bioluminous, creating light by mixing the pigment luciferin with luciferase, the enzyme that makes it glow. The light tends to green and blue, colors that travel far in seawater. Glowing helps attract mates, lure prey or confound predators.
Many of these animals live thousands of meters deep and are difficult for scientists to find and study. Here are some of the prettiest — and strangest — glowing creatures of the seas.