Have you ever used a glow stick? These fun toys produce a glowing light when you crack them, because cracking them causes the chemicals inside to mix together. Did you know some insects, fish, and fungi can produce an eerie glow, too? This glow is called bioluminescence!
Let’s dive into the brilliantly bright world of bioluminescence.
What is Bioluminescence?
Bioluminescence is a natural phenomenon found in some living creatures and organisms. This glowing light is a result of chemical energy being turned into light energy. About 80 percent of the creatures that use bioluminescence live in the oceans, while others are found on land.
How Bioluminescence Works
Have you ever seen a firefly? These small, beetle-like insects show off their glow in early summer, and they use this “attractive” lighting to find a mate.
Bioluminescence is a chemical reaction that takes place inside the creature or plant. In the case of the firefly, this energy happens inside of the insect’s abdomen. A chemical reaction happens there which creates energy in the form of photons. The photons then create light that you and I can see (along with other fireflies).
Fun Fact: The firefly’s light-producing organ is called a photophore.
However, not all creatures can produce a glow on their own. Some, like the Midshipman Fish, have to ingest it. This fish dines on tiny seed shrimp that contain the right ingredients to make it light up.
Other creatures must work together to glow. The Hawaiian Bobtail Squid, for example, glows a beautiful blue-green because of the bioluminescent bacteria that live inside of it.
Why Bioluminescence?
Different creatures and plants use bioluminescence for different reasons. Check them out!
A Glowing Defense
Some animals use their glow to warn off predators. The Click Beetle has glowing spots that make them appear larger than they really are so a hungry predator thinks twice before trying to gobble one up. Glowworms glow brightly to warn other animals that they have a nasty taste, while the Vampire Squid uses its glowing defense to confuse and startle predators. When it feels threatened, it releases a “squirty” glow right in the face of that hungry shark or whale!
Some jellyfish also use bioluminescence as a defense mechanism. If a creature or predator bumps into a jellyfish, it will suddenly flash blue or green. This blip of light is often enough to startle off most unsuspecting sea creatures.
Another unusual source of glowing is produced by a type of algae known as the Dinoflagellates (fire algae). The eerie glow produced by this unicellular algae happens when the temperature drops, either from the water moving or from something touching it.
Fun Fact: Different creatures use different molecules to glow. Most aquatic creatures use luciferin (loo-SIF-ur-in) and luciferase (loo-SIF-ur-ace), which react with oxygen to produce a green or blue light.
Glowing for Hunting Food
Some creatures take advantage of their glowing ability to hunt for food. The Black Dragon fish live very deep in the sea and are not the most handsome of critters – not only are they scaleless, but they have huge fang-like teeth inside a very large mouth. This fish also has photophores that produce light (small ones run along its body and large ones sit under its eyes). This fish also has a long “barbel” under its chin that also glows. This barbel is responsible for luring prey.
Fun Fact: The Black Dragonfish can also emit a red light that helps it locate its prey in the deep dark depths of the ocean.
The Angler Fish is another deep-sea creepy critter that uses a source of light to attract prey. Female Angler Fish have a fishing-pole like appendage that extends from their dorsal fin on their back. At the end of this appendage is a “bulb” where bacteria live. This bulb hangs over the Angler Fish’s large mouth and its glow attracts prey. Then, when they get close enough, the Angler can easily gulp them up!
A Glowing Attraction
Lastly, some bioluminescence is used for attraction–whether it be attracting a mate or, in the case of one of the several species of mushrooms, attracting flies. Flies have to be attracted to grow new mushrooms. When flies walk on the surface of the existing mushroom, then fly away, tiny spores fall from their legs. Then, new mushrooms can grow!
Fun Fact: There are about 80 species of mushrooms that can glow!
Glowing Communication
When linked together in long chains, Sea Salps (like a jellyfish) use bioluminescence to communicate with each other!
More Fun Facts About Bioluminescence
We are not finished talking about these glowing facts. Check out some more that will astound and amaze you!
Did you know…
- The Glowing Octopus is one of the few octopi that use bioluminescence. These twinkling, glowing blue-green lights run along each tentacle of this creature and are used for attracting a mate, luring prey, and self-defense.
- Cephalopods that live in the deep sea use bioluminescence all over their bodies to attract prey as they ascend to the surface of the water.
- Most sea creatures that glow do so in blue or green. These colors are more visible through seawater.
- The Kitefin Shark is one of the largest glowing creatures. It can grow to around 6 feet long!
- If you dragged a net 3,000 feet below the surface of the ocean, most of the creatures you scooped up would have the ability to glow.
- Counterillumination is when an animal uses bioluminescence to blend in with their watery surroundings.
- The Railroad worm’s head glows red while its body glows green.
That’s the Whole “Glow Show”
What do you think about bioluminescence? It’s pretty cool, right? If you had the power to glow, what would you use it for? Sea creatures, fungi, and insects all use this special ability to hunt for food, find a mate, and stay safe.
It would be a handy power to possess, but it might be tough to sleep at night with all that glowing going on!
