Built-in Underwater Polarized Lenses?
Polarized sunglasses have become the norm for humans when they want to filter out the strong glare from the sunlight bouncing off of water in a horizontal direction. But how do animals do that live in the water full time see over the glare? Over time some animals, including fish, crabs and shrimp, have evolved built-in polarized vision. In addition to helping them see underwater, mantis shrimp may use this polarization to communicate. When viewed through polarized lenses, different parts of the shrimps' body change colors—an effect that few animals besides the mantis shrimp can see. Although they aren't sure exactly what this communicates, it's exciting to think about the possibilities!