I read that the eyes of a Cuttlefish are W-shaped and are some of the most sophisticated eyes in the animal kingdom. Their peculiar shape allows them to "detect the polarisation of light" which produces an image of higher contrast that our own eyes, giving them an advanced ability to detect differences in similar colours, textures, etc. My question is how these eyes do that and what exactly is special about "polarisation of light" that causes an image with higher contrast. I looked up "polarisation of light" in wiki and I sort of understand what it is, but not how/why it is advantageous of a Cuttlefish to be able to perceive it.

 

I was torn between putting this in physics or biology, but since my question is regarding the eyes of a Cuttlefish specifically and since I already understand enough what polarisation of light is itself, I put it in here.

in terrestrial species it's used to navigate and orient themselves, but for sea critters, especially cuttelefish, it's communicative. Patterns of color change in ways humans can see, but patterns of polarization are also shifting across them.

So you're saying basically that, like we see colour and it helps us distinguish similar things, they detect polarisations of light and it's just another characteristic (like wavelength) that helps differentiate things more?

yes, its another level of differentiation for say contrast, especially advantagous in low light conditions where they live.

 

In the world of microscopy, we can change the polarization of light so that we can detect 3d surface texture of our specimens; alot of Drosophila geneticist use this form of microscopy. FYI, its called Differential Interferance Contrast or some know it as Normarski.