Glowing patterns of deep-sea sharks
Bioluminescence is known in several shark families, including lantern sharks and some other deep-water species. Light is produced by photogenic organs called photophores, which often emit blue-green light. In many species, light-producing areas occur on the underside: their glow may conceal the shark’s silhouette against faint downwelling light when viewed from below.
Illustration is AI-generated and conceptual, not documentary photography.
Luminous markings may also play a role in signaling within a species. Function depends on the species and photophore placement; not every luminous shark uses its light to attract prey, and that role is not established universally.