Once you sink deep enough into Earth's oceans, it is difficult to get sunlight. But instead of stumbling in the dark in search of food, creatures that live in extreme depths have found ways to create their own light. It is called bioluminescence and it is what gives fireflies their ability to generate bright flashes in the darkness of the night.
In the depths of the oceans, sea creatures use this ability for a variety of things, including attracting prey that could see the glow as an easy target to meet a set of jaws sharpened by their curiosity. A newly identified shark species found in the Gulf of Mexico has a very own lighting system, but it is much less intimidating than one might imagine it would be a shark that shines in the dark.
The creature is a type of pocket shark, of which only two have been found. It receives its name from small "pockets" along its sides, but it is the shark's bioluminescent properties that may be the most interesting.
The shark, which is only a little more than five inches long, is not exactly the scariest thing in the world. The only other pocket shark that was discovered was found in the late 1970s. That was a completely different species of pocket shark, and had reached maturity in a length of 16 inches. It is not clear how big this new species grows.
The shark, which has been named the American pocket shark after being found in the Gulf of Mexico, has glands that produce bioluminescent fluid. It is also equipped with photophores, which are organs that generate light, which gives the animal the ability to shine in the dark.
With a single specimen to study, and not being able to observe it in its natural habitat, it is not clear exactly how the shark uses its bright features to its advantage.
It is believed that some deep-sea fish species use bioluminescence to compensate for the shadow they cast on predators that hide beneath. With radiant skin, fish can mix with the dim light that penetrates the depths of the sea, and predators that look up could not detect them. For now, we will have to wait and ask ourselves if this shark the size of a particular pint does the same.