I actually did a bit of research on this they see colour a bit less colours than we do but still quite a few, similar to setting a file in photoshop to 512 colours (image/mode/indexed colour). Guessing there they have a range of thousands of colours not millions like we do. The other complex part is the heat pits are connected to the optical nerve in the brain so quite literally they see heat over visual images. a visual spectrum is from the end or ultraviolet to near ir for humans but snakes see farther into uv and most if not all IR. How that is overlaid with the visual information from the eyes can only be guessed at but it means that they see very well much better than humans can in low light. a CHE for example would shine like a bulb as it is warm and what we understand as temperature they see as light.
ref,
Ball Pythons Barker and Barker
the beauty of snakes BBC
Journal of herpetology london 1999
Reply With Quote