The ability to produce and emit light in the dark biochemically is called bioluminescence, and it is one of the most fascinating phenomena in the nature. While it is beautiful to look at for an observer of glow-in-the-dark creatures, bioluminescence is actually used by many creatures as part of their survival, defence and preying strategies as they use this natural ‘cold’ light to attract their prey or mates or distract predators. Humans, too, have enlarged the list with some unlikely creatures, using the advancement of science. Let us find out about such glowing animals:
There are more than 2000 varieties of fireflies, found in temperate and tropical environments. Also called lightning bugs, they have specialized light emitting organs below their abdomen. They produce light of different colours, like yellow, green, or pale red, and emit the light in blinking patterns to attract mates. The light is also a sign of its unappetizing taste.
Jellyfish is another very well-known luminous creature. With the help of fluorescent protein, photo-protein and other bioluminescent proteins, this glorious animal can create the most beautiful underwater scenario as it emits a glow from its otherwise transparent body. That’s why, it is a favourite animal for display in public aquariums.
3. Cookiecutter Shark
The cookie cutter shark, which barely comes to the surface of the sea, has a unique way of eating: it cuts off cookie-sized chunks of flesh from the body parts of its prey. The ventral part of its dark brown body is thick with cells that emit light a cold light. This light combines with the dim light filtering from the sky and blurs the familiar outline of the shark in the sea.
4. Clusterwink Snail
While glowing snails exhibit bioluminescence in the form of dim flashes in the head-foot region, the clusterwink snail is the only snail that flicker their shells like little light-bulbs. The spiral shells emit a blue-green glow in flashes as a form of self-defence. Actually, it is the shell that amplifies and diffuses the light which is produced from a single mushy spot of the snail’s body. This light shocks the predator, and even attracts the predator of the snail’s predator.
5. Bioluminescent Bacteria
Some bacteria, which live in the marine environment or the decomposition or guts of sea creatures, have the capability to produce light. Many animals live in symbiosis with these bacteria, and, in return for shelter and nutrition in their bodies, use their bioluminescence. The Angler fish, for instance, has bacteria living in its barb-like escae, which glow to give using their bioluminescence. Flashlight fish have bacteria residing in the small organs beneath their eyes while the Hawaiian Bobtail Squids give shelter to such bacteria in their mantles.
6. Arachnocampa Gnats
Also known as the New Zealand Glowworm, this fungus gnat is a luminescent creature that dwells in wet caves, humid forests and grottoes. The caves, one of the most famous being the Waitomo, are infested by these worms who form a glowing canopy as they stick to the ceilings or walls of caves, or form glow worm threads.
7. Sea Sapphire
The Sapphirina or sea sapphire is a small, parasitic crustacean or copepod. Tiny and transparent, this creature is found in the marine environment all over the world. These animals don’t glow: the sparkle. The reason behind this is the iridescent, crystal plates inside the epidermal cells which catch light and reflect it back. Different species give off different colours of light, including golden, blue, etc. This display of luminescence is only in case of the males who probably use this as a way of attracting the females. They light up, and within the blink of an eye, they are gone, creating the most stupendous experience ever for the observer.
Scorpions are neither bioluminescent nor iridescent, and they do not glow with the help of bacteria, either. They glow when exposed to ultra-violet lights of certain wavelengths. They give off a bright blue-green fluorescence under ‘black light’ and also if there is enough moonlight. Though the real reason or use of this fluorescence is not yet known, but, scientists are starting to believe that since scorpions do not like and even UV lights, they probably use this mechanism to gauge the level of light, and hence determine whether or not to come out and hunt. Of course, there could be other uses, too, like recognizing each other.
9. Firefly Squid
One marine creature that puts to rest the act of bioluminescence of all other creatures is the firefly squid or sparkling enope squid. Every year, off the coast of Japan, the firefly squids are observed to give a fascinating light show. It uses its light-producing organs called photophores which emit a deep-blue light that can be flashed on and off in unison or in various patterns. These predators flash the light to entice their prey, and also to attract mates or confuse their predators about their shape. They are seen to gather in the Toyama Bay during the months of March to May, which is their mating season. Many spiders and insects possess this ability, as well.
10. Man-made Glowing Animals
Scientists have used the sophistication of modern technology to engineer genetic alterations in different animals, like cats, pigs, sheep, fish, cow, etc. and made them into luminous creatures. According to scientists, this can help to create animals with human diseases so that those can be studied properly, and also to improve their production, as well as the quality of the products we obtain from them so that they can be better resources to human consumers.
The natural glowing mechanism comes from various methods like bioluminescence, iridescence, etc. and these mechanisms are heavily inspiring people into developing path-breaking inventions, and the glowing animals are becoming the source of the natural cold light for scientific studies.