Light suffuses our environment - without it, we wouldn't be able to see, plants wouldn't be able to photosynthesize and life as we know it wouldn't exist. Not content with such prosaic uses, some animals have evolved ways to harness light, repurposing it for bait, disguise or even outright invisibility. Let's take a look at...
The creature performs these visual feats using layers of guanine crystals and cytoplasm across its shell. These reflect any light that shines upon them, with the colour of the reflection determined by both the distance between individual crystals and the angle at which they are struck by light. This means that a blue sea sapphire can, by turning slightly, reflect only ultraviolet and "disappear" from our sight.
Notably, only the males have these colorful reflections - females take the far safer option of being completely translucent. As such, it is thought that male sea sapphires use these bright lights to attract a potential mate.
Not content with these talents, this cunning crustacean has developed reflectors that allow it to polarize light. Communicating with polarized light allows the shrimp to "cipher" any signals it sends out - and may help it evade other (less optically-gifted) predators!
It's unclear why the snail does this, but some researchers speculate that it may be a "false flag" to ward off firefly larvae attacks. The snail uses the same combination of luciferin and luciferase as a firefly, and the glow could give a hungry grub the impression that the snail had already been "claimed" by a predator.
The squid depends on iridocytes (specialized cells dedicated to reflection) to perform this visual feat. When triggered by "reflectin" proteins the cells contract, altering how much light they reflect and allowing the squid to alter its appearance. Think of it a bit like increasing the saturation of a single colour in photoshop.
Anglerfish lures are actually pouches filled with bioluminescent bacterium. The fish uses a flap of skin to "shutter" the lure if it wants to hide, or even to flicker the light on and off in the hopes of drawing more attention - similar to the shuttered lanterns favored by smugglers!
This light is produced using a reaction between luciferin and the enzyme luciferase that produces a steady glow. The beetle can even control this light to an extent, meaning it can be muted or displayed as a toxicity warning.
Railroad worms can have a red "headlight" in addition to the yellow-green side markings. Few insects and spiders can actually perceive red light, meaning that this red light is effectively invisible to most of the predators and prey of the railroad worm. Armed with this headlamp, the railroad worm can navigate and hunt in the dark without giving itself away.
- The Sea Sapphire
- The Mantis Shrimp
- The Glowing Snail
- The Squid
- The Anglerfish
- The Railroad Worm
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| Mantis shrimps have a knack for using polarized light... (Eychenne) |
1. The Sea Sapphire
A tiny marine crustacean, the sapphirina, or "sea sapphire" literally sparkles in the ocean. They come in a variety of colors (including red, blue, violet and green) but the biggest trick of the sea sapphire is to vanish entirely.The creature performs these visual feats using layers of guanine crystals and cytoplasm across its shell. These reflect any light that shines upon them, with the colour of the reflection determined by both the distance between individual crystals and the angle at which they are struck by light. This means that a blue sea sapphire can, by turning slightly, reflect only ultraviolet and "disappear" from our sight.
Notably, only the males have these colorful reflections - females take the far safer option of being completely translucent. As such, it is thought that male sea sapphires use these bright lights to attract a potential mate.
2. The Mantis Shrimp
The mantis shrimp is best known for the claws it uses to strike, hammering home at speeds of over 50 miles per hour and generating a secondary shockwave that can crush organs even if the initial strike misses. Less well-known is that they have independent eyes set on mobile stalks with three focal points, giving them some of the best eyes on Earth.Not content with these talents, this cunning crustacean has developed reflectors that allow it to polarize light. Communicating with polarized light allows the shrimp to "cipher" any signals it sends out - and may help it evade other (less optically-gifted) predators!
3. The Glowing Snail
Unique among snails, the blinking snail is the only terrestrial gastropod that produces bioluminescence. Found in Singapore, this mollusk emits a faint pulsing yellow-green light when moving, maintains the pulse at half speed when feeding and doesn't pulse at all when at rest.It's unclear why the snail does this, but some researchers speculate that it may be a "false flag" to ward off firefly larvae attacks. The snail uses the same combination of luciferin and luciferase as a firefly, and the glow could give a hungry grub the impression that the snail had already been "claimed" by a predator.
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| Squid use light to camouflage themselves.. (sailormn34) |
4. The Squid
Many cephalopods are able to change their coloring, so as to better blend in with their surroundings. Researchers investigating the "opalescent inshore" or "market" squid found that this trick was accomplished not by releasing pigments into their cells, but by fine-tuning the light they reflect.The squid depends on iridocytes (specialized cells dedicated to reflection) to perform this visual feat. When triggered by "reflectin" proteins the cells contract, altering how much light they reflect and allowing the squid to alter its appearance. Think of it a bit like increasing the saturation of a single colour in photoshop.
5. The Anglerfish
Debatably the ugliest animals to exist on earth, deep-sea anglerfish are best known for their bioluminescent lures. These are mounted above the cavernous mouth of the fish and stick out like a fishing pole - which is essentially what they are. When an unsuspecting creature swims up to inspect the lure, the maw of the anglerfish opens wide and draws the prey in with suction - lunging forwards could push the prey out of the way thanks to water pressure.Anglerfish lures are actually pouches filled with bioluminescent bacterium. The fish uses a flap of skin to "shutter" the lure if it wants to hide, or even to flicker the light on and off in the hopes of drawing more attention - similar to the shuttered lanterns favored by smugglers!
6. The Railroad Worm
Despite the name, the female railroad worm is actually a beetle with a larvaiform (elongated like a grub) body. The beetle takes its name from the row of green-yellow lights that run down the female's body, giving it an uncanny resemblance to a train carriage in the night.This light is produced using a reaction between luciferin and the enzyme luciferase that produces a steady glow. The beetle can even control this light to an extent, meaning it can be muted or displayed as a toxicity warning.
Railroad worms can have a red "headlight" in addition to the yellow-green side markings. Few insects and spiders can actually perceive red light, meaning that this red light is effectively invisible to most of the predators and prey of the railroad worm. Armed with this headlamp, the railroad worm can navigate and hunt in the dark without giving itself away.
Thanks for reading...