The mantis shrimp (which oddly is neither a mantis nor a shrimp, but a crustacean that resembles both) has arguably the most complicated visual system of any animal on Earth. Its compound eyes sit on independently moving stalks and can see colors ranging from ultra-violet to infra-red. Each eye is divided into three regions for tracking motion, forms, depth, and color. All of this, it is theorized, is done without the aid of its tiny brain. (It's also got claws that can smash through glass, but that we'll save for another article). Now add to this an entirely new kind of vision previously unknown: the mantis shrimp can see circular polarized light.
We humans can see the effects of linear polarized light when we put on polarized sunglasses and go out on a boat. Linear polarization is observed when transparent materials reflect light, so on a sunny day, the ocean's surface will look glassy to us. Put on polarized sunglasses and the glare is eliminated. Circular polarization is a bit more complicated. It has to do with out-of-phase stereo imaging, which can best be explained by the effect you get when you put on 3-D glasses and watch a movie in 3-D. That's circular polarization.
Why the mantis shrimp has the ability to, in effect, put on 3-D glasses is still a mystery. But Professor Justin Marshall (the researcher who discovered it), from the Queensland Brain Institute, surmises it has something to do with sex. Only the males are able to see this way, so his theory is it is some as of yet unknown communication for mating. "[We] humans only have three color channels," he said. "These little guys have 12, and can see both linear and circular polarized light—it is remarkable."
That's wicked. Don't ants and other insects also see polarized light, as an aide to navigation?
i don't think ants see anything spectacular, the use there antennas to sense
While it would seem that a majority of ants have poor/no vision, there are some that do have amazing capabilities related to their visual systems...
Most arthropods have the capacity to see linearly polarized light as an intrinsic characteristic of their photoreceptor structure. Mantis shrimp are unique is being able to see circularly polarized light, which they achieve using a biological 1/4 waveplate; converting circularly polarized light into linearly polarized light, which their photoreceptors can interpret.