On of the wonders of the natural world is Bioluminescence, which is light produced by living organisms. There are thousands of plants and animals in the ocean and on land that are able to produce their own light. They use this light to signal other creatures, whether to find a mate, to distract or frighten predators, to camouflage themselves, or to illuminate their prey. Most creatures have chemical reactions inside special light organs, although other creatures have to consume luminous prey to obtain the supply of the right chemicals. A few glowing fish and squid cannot do neither actions, yet they still sparkle because their light organs are home to luminous bacteria: when the bacteria glimmers, so does the creature. Just like a flashlight or traffic lights, the light organs have complicated lenses, reflectors, and color filters that make them work efficiently.
Angler Fish
The deep-sea anglerfish live in the depths of the ocean, where it is always pitched black because no sunlight can reach that far down. The anglerfish survives by making its own light. The fish has a fin, in the shape of a fishing rod, growing from its snout. At the end of the fin is the glowing light that acts as bait to tempt prey into the range of the anglerfish's huge mouth. The mouth contains rows of long, curved teeth that lie backwards so that once the prey is in the mouth; there is no way to escape. Anglerfish feed on small fish, squid, crustaceans, worms, and any other creature they can catch. The prey usually mistakes the blob of light for a tasty snack. Anglerfish are sluggish swimmers; they do not have a streamline body because they do not need to move swiftly to catch their prey. Female anglerfish are 6 inches long and males are smaller.
Firefly
Also known as glowworms, these creatures are usually seen as bright flashing lights dancing in the air and lighting trees on a summer's night. Fireflies are a type of beetle, and they are famous for their yellowish-green lights, which they produce in their body. Only male fireflies have wings, but they are smaller than females, and their lights are not as bright as the females. In some species, the males flash first to attract a female, while in other species, the female does the “calling.” Their lights are also used to defend themselves, giving a signal to enemies that they taste bad and should be left alone. Both male and female die soon after mating.
Flashlight Fish
These fish are only active at night. During the day, the fish usually hides under rocks. It is very sensitive to light and will immediately dart for cover if the moonlight is too bright, or if it is exposed to a human driver's torch. Since it only feels safe under complete darkness, the flashlight fish use their own light to communicate with each other, capture prey of plankton and crustaceans, and to confuse predators. Light organs that are located under each eye produce their lights. Each organ consists of millions of luminous bacteria that emit light as they are nourished by sugar and oxygen in the fish's blood. The fish are able to control their lights, meaning that they can turn them on and off. If a predator has startled a flashlight fish, the fish would turn off its light, causing complete darkness and would turn on its lights elsewhere. It would repeat the process in a maze-like, zigzag, escape route that would confuse the predator. The beams of light created by the fish are so powerful that they can be seen more than 100 feet away. In fact, they are powerful enough that one flashlight fish can light up a small room.
Railroad Worm
The railroad worm is not a worm at all, but a worm-like adult female or the larva of the Phrixothrix beetle. Phrixothrix means “with bristling hairs” and refers to the covering of tiny hairs on its body. The railroad worm gets its name because it looks like the windows of a night train, with a bright red headlight at the front. It lives in South and Central America, and is rarely seen because it is shy and nocturnal, meaning it only comes out at night to hunt food. It mainly feeds on insects and millipedes, often much larger than itself. It glows as it curls around its prey and kills it with a poisonous bite from its large, curved jaws. It is known to eat other railroad worms. If threatened, it will suddenly turn on its bright lights to warn the predator to stay away. It also lights up while mating. It has a greenish-yellow body and only the females have the bright red light at their head. The lights are produced by chemical reactions in the body. It has eleven spots that are able to shine a light. The railroad worm can turn all the lights at once or just turn on a few at a time. During the day, however, the railroad worm is brown in color, which camouflages them as it hides under rocks and logs or even underground.
