Did you know that about 50 species of sharks can produce their own light to glow in the dark? And each flashes a pattern unique to its own species, a recent report in PLOS ONE reveals.
The velvet belly lantern shark, like other lantern sharks, camouflages itself with flashing lights of its belly.
These sharks live in the ocean’s twilight zone, where little light penetrates. Their specially designed, extra-sensitive eyes apparently measure the color and intensity of sunlight above, allowing them to mimic it with similar flashes and sparkles on their bellies. They use this amazing talent to hide in the light. When predators or prey below them look up, instead of seeing the sharks’ dark silhouette against a lighter background, they see unbroken sunlight. The sharks can maintain this light camouflage, even as conditions change from moment to moment. The glow on their bellies enables them to hide from enemies below and to sneak up on prey.
Bioluminescent sharks’ eyes are more light-sensitive than those of sharks that do not glow, and each species’ eyes are tailored to get a good view of the places they most need to see. Those that live on the bottom, for example, have especially sensitive regions in their retinas that give them a clearer view of the ocean floor. Some also have eyes designed to process visual information quickly so they can pick up the brief bioluminescent patterns of other sharks of the same species.
While we tend to focus on sharks’ predatory nature, some are quite vulnerable, such as one lantern shark species only 19.5 inches (50 cm) long—just a good-sized bite for a bigger fish. In a fallen world where predator and prey must remain in balance, God has equipped bioluminescent sharks to locate their friends and their dinner while they avoid becoming dinner themselves.