There are around 500 different types of mantis shrimp in the world, large territorial shrimp that live in warm tropical waters. They see the world in ways we can’t imagine, and it all begins with light.

Light is a type of energy that exists as both a particle and a wave. These light particles are known as photons and are emitted from various sources such as the Sun, which shrines bright throughout our solar system and interstellar space. When light hits a surface, it reflects back to the rods and cones in our eyes which the brain then processes as an image. 

As a wave, light is composed of both electric and magnetic fields, which can be thought of as spaces holding invisible forces that move in a specific direction. When emitted from the Sun, the light's electric field travels in all directions and makes up the part of the electromagnetic spectrum known as visible light which humans can see. Like humans, mantis shrimp can see visible light, but they have the ability to see ultraviolet and polarized light as well.

Recall that visible light makes up a small part of the electromagnetic (EM) spectrum, a range which shows the wavelengths and frequencies of different types of light. Ultraviolet light has a little more energy than visible light, and is what gives you a tan (or sunburn!) if you stay out in the Sun too long. Polarized light doesn’t have its own section on the EM spectrum–it’s actually visible light that has hit an odd surface, like water, causing its electric field to move in a linear or circular direction. Humans can detect this polarized light though–it’s that gleaming shine that bounces off the ocean and makes it difficult to see the water, and is why fishermen use polarized sunglasses to see through the waves. 

But how do we know that mantis shrimp have this ability? Why did they evolve to be that way?

Scientists know this through behavioural studies and dissections. Shrimp benefit from this trait since it allows them to see crab shells or other objects that reflect light and are potential food, and scientists tested this in labs, recording shrimp behaviour under different lights. We have a deeper understanding of their anatomy through looking closely at structures in their eyes–mantis shrimp have a midband across the eyeball full of light-sensitive cells along with structures that can uncurl circular polarized light. Mantis are the only known animal in the world that can do this. 

Most mantis shrimp fall into punching and spearing groups, and you can see both at the Boca Aquarium! It’s shrimply the best! 

Written by Val