Bioluminescence (light produced by biological organisms) can be entrancing. The soft glow of fireflies at night is a common sight in places around the world, but not all cases of bioluminescence are so peaceful.

Although the firefly uses its glow for communication and finding sexual partners, bioluminescence isn’t always an invitation. Sometimes, it is used as a diversion or as camouflage.

The natural world is a fierce place, and any advantage can mean the difference between life and death. These 10 examples of biological light are used by animals as a way to defend and deceive.

10 The Glowing Squirts Of The Pocket Shark

In a happy accident in 2010, researchers in the Gulf of Mexico were collecting samples for a study of sperm whale feeding and happened to capture a specimen of an entirely new species of pocket shark. These sharks are only 14 centimeters (5.5 in) long.

This one wasn’t recognized as a pocket shark until 2013 when the specimens collected were further examined. It’s an understandable mistake as the only other known type of pocket shark makes its home in the Pacific Ocean and not the Gulf of Mexico.

Out of the 500 or so species of sharks in the world, this newly discovered one has an unusual talent. Tucked next to each of its two front fins is a pouch filled with bioluminescent liquid. This glowing concoction can be released at will, creating small clouds of glowing . . . squirt.^[1]

The pocket shark uses these glow-in-the-dark clouds as bait for prey attracted to the light—like moths to a flame. Easily gathered prey ripe for the picking.

9 The Anglerfish’s Glowing Fishing Pole

The anglerfish (of which there are some 200 species) lives deep in the inhospitable oceans—so deep that sunlight cannot filter through the murk. But that’s all right because the anglerfish brings its own light.

Female anglerfish have a section of dorsal spine that sticks out from their foreheads like a fishing pole. On its tip is a glowing orb. As with other fishers, this pole has bait. The light attracts prey, and when they get in range, the anglerfish attacks with its massive crescent-shaped mouth filled with skinny, translucent teeth.

The anglerfish’s body is so pliable that it can consume prey up to twice as large as its own body. This is a feat because the largest anglerfish can grow more than 1 meter (3 ft) long.^[2]

8 The Hawaiian Bobtail Squid’s Million Army Invisibility

During the day, this bobtail squid hides in the sands off the coast of Hawaii. But at night, it must leave this safety to hunt while avoiding being eaten itself. It does this by means of some enlisted help.

In the Hawaiian bobtail squid’s mantle is an organ specially designed to harbor a culture of bacteria. But this is no infection. In fact, the Hawaiian bobtail squid invited these microorganisms less than a day after it was born by using a special mucus to attract the bacteria to its body.

The bacteria produce just enough light to perfectly match the illumination of the Moon in the ocean waters. This allows the Hawaiian bobtail squid to blend seamlessly into its surroundings and remain safely hidden from predators while on the hunt itself. All because of millions of small guests. Meanwhile, the bacteria benefit from the sugars and amino acids provided by the squid.^[3]

7 The Red Searchlight Of The Black Dragonfish

Most bioluminescence in the ocean is a blue color. Perhaps it’s no coincidence because those colors are easily visible to most ocean-dwelling creatures and shine far through the water. In contrast, red light is quickly absorbed by the ocean. Also, most animals are not equipped to perceive colors like red or yellow.

One notable exception is the black dragonfish. It produces a short wavelength color, like blue, and then filters it through a fluorescent pigment while still inside its body. This lengthens the light and turns it red before it is emitted into the ocean. But why bother when red light doesn’t travel far?^[4]

This dragonfish is special because it can produce red light as well as see it. Very few marine creatures can. This gives it a huge advantage when hunting for food. Its red spotlight allows it to see prey while the prey remains blissfully blind and ignorant. The black dragonfish produces light that only it can see, giving it a huge strategic advantage in ocean combat.

6 The Deadly Shine Of The Bioluminescent Octopus

With tentacles reaching 36 centimeters (14 in) from its body, the Stauroteuthis syrtensis, or bioluminescent octopus, is a beautiful sight for two immediately apparent reasons. The first is a webbing that connects its tentacles, giving it an imposing umbrellalike shape. The second noteworthy feature is that its suction cups are modified to emit a powerful twinkling blue-green light.

The purpose of this light is hard to determine because this octopus lives at depths up to 4,000 meters (13,100 ft) below the ocean’s surface. However, its diet primary consists of small planktonic crustaceans which have well-developed and sensitive eyes that are attracted to light sources.^[5]

This bioluminescent octopus likely dazzles the crustaceans with both sustained and pulsing lights. Once they’re close enough, it uses a mucous web to entrap the crustaceans and usher them to their fate.

5 The Cookiecutter Shark’s ‘Broken’ Camouflage

The cookiecutter shark employs a tactic similar to that of the Hawaiian bobtail squid, which uses light to vanish from predators by matching the light from above. Using photophores that are mostly on its stomach, the cookiecutter shark practices a method of counterillumination that hides its body from predators that would otherwise easily see and eat it.

The photophores mask the cookiecutter’s entire body—with one notable exception. Around its neck is a “collar” that has no photophores, creating a gap of counterillumination. Most of its body is concealed, except for this small portion of neck which is clearly visible.

This may seem like a design flaw because surely the most effective camouflage would be complete. But that gap in the shark’s camouflage turns its defensive ability into an offensive one.

As only a small section is left visible, it acts as a lure for would-be predators that believe they’re attacking a much smaller fish. However, these opportunists are not equipped to deal with the much larger reality.

When they attempt to eat the exposed neck, they are faced with the cookiecutter’s powerful suction and razor teeth. After the shark latches onto the would-be attacker, the cookiecutter spins its body wildly, scooping a section of flesh from its unsuspecting victim.^[6]

4 The Green Bombs Of The Swima Worms

On the seabed off the West Coast of the United States lives a genus of sea worms named Swima that are designed like a long rowboat. They have rows of fan-shaped bristles that they use as paddles to maneuver in the ocean depths.

These bristles give them their distinctive design, but their truly outstanding feature is found in a small cluster near their heads. Small green-colored gills give the Swima their nickname: “The Green Bombers.”

When the worm is attacked or disturbed, it detaches one of these green “bombs” and deploys it as a distraction. Once detached, the gill begins glowing an intense green to divert attention from the worm itself. Meanwhile, the Swima uses the opportunity to swim away from danger. All told, each worm comes equipped with about eight of these bombs at any given time.^[7]

3 The Squid Willing To Make Sacrifices

The Octopoteuthis deletron is a squid in the cold Pacific depths that takes the tactic favored by the green bomber to the extreme. To ward off its many predators, this squid is willing to make grave sacrifices for survival.

If put in a life-threatening situation, it latches onto its attacker with its limbs and then severs those limbs. While the squid attempts to flee, its sacrificed tentacles flail about and emit light, all in an attempt to distract the attacker long enough for the squid to get away.^[8]

It’s a dangerous gamble because regrowing limbs costs energy, which will be harder to come by when swimming and feeding with missing appendages. But as cephalopod researcher Stephanie Bush said, “The cost is less than being dead.”

2 The Milky Glow Of The Hitchhiker Bacteria

In 1995, the SS Lima, a British merchant vessel, encountered an expanse of the ocean that glowed a milky white color. For six hours, the vessel sailed through what the captain described as an expanse much like snow or clouds.

This stretch of glowing ocean may have felt like something out of a fairy tale, but it was actually the result of an enormous colony of bioluminescent bacteria. These glowing bacteria float freely in the ocean, though not usually in such large groups as the Lima encountered.

But glowing takes energy, and no life-form wants to waste its strength needlessly. As it turns out, the emission of light is an invitation. Most creatures on this list use their bioluminescence to avoid being eaten, but these ocean bacteria use it for the opposite.

The glow is an invitation to fish and squid to chow down on the bacteria. After all, a fish’s stomach is full of nutrients and the fish can carry the bacteria much farther than they could float alone.^[9]

1 The Fire-Spitting Shrimp

Acanthephyra purpurea is a species of shrimp that is not bioluminescent at all. In fact, it appears to be like an average shrimp. If you caught it on a calm day, it would have nothing to attract your attention. It has no photophores and no illumination from its body at all.

What it does have is a biological way to produce and store a chemical compound called luciferin. In the event of an attack, this shrimp spews out the luciferin in what would appear to be vomit to the layman.^[10]

When the chemical compound comes into contact with the ocean water’s oxygen, it creates a chemical reaction that glows. This luminous display looks almost like a blue fire. It should give the shrimp the distraction it needs to make a hasty retreat and live to spit fire another day.

In war, strategy is everything. A single well-executed maneuver can be the difference between victory and defeat. This was certainly the case with the Trojan Horse, a brilliant tactical move that allowed the Greeks to take control of Troy. But, while the story of the Trojan horse may be a thing of fiction, the use of wacky but clever ploys in war is not.

Here is a list of some of the most clever deceptive tactics that have been used in war throughout history.

10 Fake Paris in World War 1

Paris is a city rich with history that stretches back centuries. But during World War I, German bomber planes flying by night were an imminent threat to the iconic landmarks of the French capital. The French came up with a pretty ingenious plan to build a fake Paris replica out of wood and canvas, complete with lights, so that it would fool the German pilots at night.

The decoy city would be located just outside the real Paris, and it would be designed to confuse and lure the German pilots away from their true target. Fortunately, the war ended shortly after construction began, so the plan was never fully realized. The story of the fake Paris is a reminder of the lengths that people will go to in times of war. It is also a testament to the power of human ingenuity and creativity, even in the face of adversity.^[1]

9 German City Does Not Go Dark to Avoid Bombing

Like France, German cities were also terrorized by nighttime air raids. In World War II, one German city called Konstanz, which sits near the border of Switzerland, was able to elude bombardment by refusing to turn out the lights after dark. In order to protect itself from nighttime air raids, German cities were forbidden from using any lights. Street lamps and buildings went dark, and citizens were not allowed to use candles and had to cover their windows with curtains or black paint.

On the other hand, their Swiss neighbors—who were neutral in WWII and thus not targeted by the Allies—remained illuminated at night. By keeping their lights on, Konstanz was able to fool the Allied forces into thinking they were part of Switzerland and managed to make it through the war mostly unscathed.^[2]

8 Ghost Army

If you think deception is an art, then the U.S. Army took it to new heights during World War II. They went so far as to gather a team of artists and audio experts to create an elaborate phantom military unit of inflatable tanks and phony sound effects and radio transmissions to fool the Nazis.

The 23rd Headquarters Special Troops, also known as the “Ghost Army,” was made up of around 1,100 soldiers who were tasked with creating lifelike dummy tanks, trucks, and artillery. They also played recorded sounds of battle to make it seem like there were more troops than there actually were. The bluff created a distraction that tied up enemy resources and preoccupied them with a military presence that wasn’t really there while the real Army maneuvered elsewhere.^[3]

7 Foiled Camisade During the War of 1812

During the war of 1812, one town on the coast of Maryland managed to fool the British during a nighttime siege. St. Michaels was a shipbuilding town targeted by British forces approaching via the Miles River. When an attack by the British became imminent, the townspeople decided to take action.

They placed lanterns in the treetops around the town, making it appear as though the town was at a higher elevation than it actually was. When the British rowed onto shore in the night, they were met with cannon fire by the Americans. This drove them back to their ships, from which they fired upon the town. Because they aimed at the lights in the trees they thought were windows and buildings, they ultimately shot over the town and failed to hit anything.^[4]

6 Army Builds a Fake Base to Fool Saddam Hussein

The Gulf War was fought in the early 1990s as a coalition of forces from more than 30 countries sought to liberate Kuwait from Iraqi occupation. Before the first bombs fell on Baghdad in 1991, the U.S. military was engaged in a battle of wits with Saddam Hussein. The Iraqi dictator had invaded Kuwait and was dug in for a long occupation. In order to drive him out, the U.S.-led coalition needed to mount a surprise attack. But how could they keep Saddam guessing about their plans?

The answer was Forward Operating Base Weasel, a secret military base set up for the purpose of deceiving the Iraqi leader. By sending out false radio signals, including recorded Egyptian radio traffic about the Americans and planting bogus intelligence, the coalition was able to convince Saddam that the main attack would come from the south when in reality, it would be coming from the west. It was a daring plan, and it worked like a charm. Thanks to the brave men and women at Forward Operating Base Weasel, Saddam was caught off guard when the real attack came, and his forces were quickly routed.^[5]

5 Vietnam POW Plays Stupid to Deceive Captors

Douglas Brent Hegdahl III was only twenty years old when he was taken captive by the North Vietnamese during the Vietnam War. A Navy seaman, Hegdahl had been on a ship in the Gulf of Tonkin when he fell overboard and was picked up by a North Vietnamese fishing boat. Hegdahl was immediately taken prisoner and spent the next two years in captivity.

During that time, he developed a deep understanding of the Vietnamese language and culture. However, he was able to fool his captors into thinking he was stupid and harmless. He exaggerated his country accent and expressed a fascination with communism. As a result, he was treated relatively well and was dubbed “the incredibly stupid one.” He was allowed to roam the POW camp freely and would secretly sabotage the Vietnamese by doing things like putting dirt in gas tanks to disable them. He was eventually released as part of a prisoner exchange. After returning to the United States, Hegdahl was tapped for his knowledge about the Vietnamese as part of negotiations for ending the war.^[6]

4 Hannibal of Barca Tricks Romans

A trap is only as good as its bait, and when it comes to luring in his enemies, Hannibal of Barca is a master angler. In 216 BC, the Carthaginian commander found himself and his army cornered in a valley in Campania. Unfortunately, his army was situated in a valley with Romans guarding the only way out—a mountain pass.

Seeing no other way to escape, Hannibal took a herd of cattle and stampeded them toward the pass with flaming torches on their horns. The guards, thinking the cattle were Hannibal’s soldiers, rushed to confront them and his army safely slipped away under cover of night. It’s a story that has gone down in history as one of the most clever military maneuvers, and it’s a testament to Hannibal’s resourcefulness as a leader.^[7]

3 Operation Mincemeat

In 1943, British intelligence came up with an outlandish plan to deceive the Nazis that sounds straight out of a spy flick. The plan, codenamed Operation Mincemeat, involved planting false documents on the body of a dead man and releasing the body into the sea off the coast of Spain. The corpse was that of a homeless man but was given a fake identity to pass off as a dead British officer.

The hope was that the Germans would learn of the corpse and believe the contents of the phony documents attached to it. The plan was successful, and the Germans were led to believe that the Allies were going to invade Greece and Sardinia rather than Sicily. As a result, they diverted troops to these areas, which helped ensure the success of the Allied invasion of Sicily. Operation Mincemeat is now considered one of the most successful deceptions in military history.^[8]

2 Opium-Laced Cigarettes

In World War I, the British and the Ottomans were embroiled in a slow, drawn-out battle in the trenches. Eventually, the British learned that the Ottomans had run out of cigarettes, at which point they sent packs to the enemy. However, the action was far from altruistic as they also attached propaganda in an attempt to demoralize and taunt their adversaries.

The Ottomans willingly took the smokes but defiantly discarded the propaganda, showing no intention to surrender. The British prepared to raid the enemy but, before doing so, sent over more cigarettes, this time laced with opium. By the time the British launched their attack, it was an easy victory as their enemy was too strung out to put up much of a fight.^[9]

1 Cats on the Battlefield

Back in 525 BC, a war was waged between the Persians and Egyptians. In the battle of Pelusium, the battle-tested Persian leader Cambyses II was able to get the best of Egypt’s young inexperienced pharoah, Psametik III. In Egyptian culture, cats and other animals were held as sacred. Cambyses II knew this, and according to ancient accounts, he had his army show up to battle with images of cats painted on their shields.

Additionally, Persian forces released a large number of cats, dogs, and sheep onto the frontlines. The Egyptians were fearful of causing harm to these animals and were so alarmed at the sight of Persian soldiers throwing cats at them that they fled in panic. As a result, many Egyptians were slain in the process, and the Persians were able to take control of Egypt with relative ease.^[10]