Beyond Rainbows
Most animals can tell how fast the electric field in a light wave is oscillating, which is perceived as color.
Blue light oscillates, or vibrates, faster than green, for example, and both of those colors are faster than red. The oscillation's direction is known as polarization.
Many animals, from parakeets to ants, can see linear polarization—what happens when light follows different angles after it's reflected off of water or a transparent membrane such as a fly's wing.
Bees and some birds navigate by polarized skylight, and fish and crustaceans use polarization for navigation and seeing prey.
But mantis shrimp are the first animals known to see both linear polarization and a much rarer type called circular polarization.