Animal with best eyesight?

that would be....


...not a potato

...not a peregrine falcon

...not a sight hound, but

this guy:

(Source 1)

(Source 1)

(Source 1)

~~~~~~~~~~~~~the Mantis Shrimp~~~~~


How many cones? is the question to ask when finding out who has the best vision.  For comparison...


Dogs - 2 cones (they can't see red)
Humans - 3 cones
Butterflies - 5-6 cones (they can see ultraviolet that we can't see)
Mantis Shrimp - 16 cones!  This is the most complicated visual system of any animal we know by 50% (Source 2).


More about these crustaceans...


"Mantis shrimp possess the animal kingdom’s most complicated eyes, capable of distinguishing between 100,000 colors — 10 times as many as humans — and seeing circular polarized light, or CPL, which can’t be detected by any other creature [Wired.com]. Circular polarized light is one of two forms of polarized light, or light waves that travel in a specific plane. 


[...]  


The mantis shrimp is one of the few animals that reflects circular polarized light off its skin; since other shrimp can see that reflected light, it serves a communication function.  Says lead researcher Justin Marshall: “They’re talking to each other with a secret light channel”." (Source 3)


So maybe they have amazing eyes because the better their eyes are, the better they can interpret the skin light-show-communication of their fellow shrimp, so it's evolutionarily advantageous for them to have these sharp eyes.


For instance, say if Bobby Shrimp flashes blue tailfin, which means in shrimp - Look out! Giant octopus!, then Shirley Shrimp has a better chance of surviving if she can understand this quickly and respond with her eagle shrimpy eyes, but Amanda Shrimp perishes because her eyes only see 90,000 colors instead of 100,000.

(Source 3)

(Source 4)

Bibliography:


1. "Mantis Shrimp Amazing Beautiful" blog post by x. PlanetAnimalZone, 2011-12.  WWW: http://planetanimalzone.blogspot.com/2012/05/mantis-shrimp-amazing-beautiful.html.


2. "Colors" radio podcast by RadioLab.org.  Originally broadcast May 2012.  RadioLab, WNYC Radio, 2012.  WWW: http://www.radiolab.org/2012/may/21/.


3. "Shrimp Eyes Polarize Light Just Like a DVD Player, Only Better" article by Will Ramos.  Posted 2009. Consortium for Ocean Leadership, 2007-11.  WWW: http://www.oceanleadership.org/2009/shrimp-eyes-polarize-light-just-like-a-dvd-player-only-better/.


4. "Mantis Shrimp Eyes - The Coolest High-Def Devices Nature Has to Offer" YouTube video posted by trustusonline, 2011.  WWW: http://www.youtube.com/watch?v=zTF4PBb0h9g.