This shrimp's eyes have up to 16 types of color receptors — humans have just three
Mantis shrimp eyes contain as many as 16 different photoreceptor types, compared to the three humans use for color vision, letting them detect ultraviolet and polarized light invisible to us. Oddly, researchers have found their brains don't combine these signals the way human color vision does, so having more receptor types doesn't necessarily mean they perceive dramatically more colors, just differently.