The Peacock Mantis Shrimp seems to have the ability to camouflage itself with naturally-occurring biotech that makes it practically invisible. The invisibility super power of the Mantis Shrimp might be unique among animals. To understand how it works, we need to appreciate that there are different forms of light. The shrimp has the ability to see a type that we aren’t even aware of.
Invisible light waves
To understand how the Mantis Shrimp gets its super powers, we first have to understand a little bit about light.
Light is an electromagnetic force, which means a combination of energyEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More and magnetism. And there are numerous frequencies we can’t see like ultraviolet and infrared. There are also three types of polarized light: linear, circular and elliptical. A rare minority of people can see some linear polarized light.
Linear polarised light is the easiest to explain.
Light travels in waves. It’s like a skipping rope whipped up and down, side to side or on any angle. The wave is flat and the undulations travel along the length of the rope. Energy waves from a lightbulb vibrate in numerous directions. But sunlight that reflects off the sky and water, bounces off in a single flat plane, like the rope.
The computer or phone screen you are reading this on, emits polarised light. I have an iPhone. When I put on sunglasses, I can’t see the screen unless I turn my head to one side. Polarising glasses have a thin film with molecules arranged in vertical stripes. When they line up with lightwaves, the molecules absorb the energy and we can’t see it. This is how you can see through water wearing them. The polarised light that would impeded your view is filtered out.
Light waves can multiply or become invisible
If you recall basic school physics you’ll also know you can add or subtract waves. Two perfectly overlapping one-metre-high waves become two-metre waves. Or you can cancel them out by overlapping a 1m peak and a -1m trough to make no wave.
If you’ve ever tried surfing or body-boarding at a beach you know the decent waves appear in batches. This is because you can have two sets of surf emanating from two separate storms hundreds of miles away. One travels slightly faster than the other. If you’ve sat in a vehicle with the indicator lights of the car in front slightly out of sync, they drift in and out of sync over time. There will be times surf is poor as the waves misalign and cancel each other out. Other times the peaks coincide and the waves grow heaviest.
Light waves do the same except they contain both an electric wave field and a magnetic wave field. When these interact, they polarise.
Circular polarised light occurs because of magnetism
Now imagine two pairs of children side by side, where each pair is holding a highly magnetised skipping rope. Each pair waves their rope up and down but at a 45° angle to the other pair. When the top of the skipping rope peaks are closest, the ropes will be stretched sideways by the magnetism, which sets up a twisting motion.
In light, electric and magnetic waves grow and cancel each other out but magnetism also attracts the waves towards each other. Now, when you combine two waves of different dimensions and speeds in three-dimensional space, it can set up a spiral around the direction of travel.
If you want to dig deeper, you can watch this YouTube video.
The Mantis Shrimp cloak of invisibility
The cone-cells in our eyes perceive red, green and blue (which are the colours we use to transmit colour images on our TVs). Mantis shrimps have four times more colour-detecting cells and are therefore, theoretically capable of seeing many more individual colours. You’d think this gives them far superior colour sensitivity but it doesn’t.
We don’t know how Mantis Shrimp eyes work but in experiments, they are non-plussed by colour variation. It seems that colour doesn’t serve a particularly useful function(Of an ecosystem). A subset of ecosystem processes and structures, where the ecosystem does something that provides an ecosystem service of value to people. More in Mantis Shrimp lives.
However, Mantis Shrimps are currently the only group of animals known to be able to detect circular polarised light using arrangements of nanocrystals in their eyes[87]. Not only that, they have structures embedded in their shell that can reflect it for territorial purposes, mating and defence. It’s thought this is an ideal way to hide in plain sight.
If you are an animal that reflects circular polarised light, you might be practically invisible to others. You are less likely to attract attention from predators, none of whom can see these patterns. You might also be able to sneak up on your prey. The invisibility super power of the Mantis Shrimp is because they can use linear and circular polarised light to their advantage.
It’s yet another example of how much we don’t understand our world. We have to be very careful when interpreting the way the planet works as our own senses are only one way to see.
Gagnon, Y., et al., Circularly Polarized Light as a Communication Signal in Mantis Shrimps. Current Biology, 2015. 25.
