I have a dim recollection that cats have alot more, er, rods? (motion detectors) than, er, cones? (color detectors).
Our color-detectors tend to be in a might tighter clump than our motion-detectors, and I gather this is generally true for organisms with color vision. This explanation I heard was that this was to give us motion-detecting peripheral vision. For detecting whether something is leaping out of a tree at you, you don't need to visually parse its details, you just need to know it's approximate trajectory and velocity so you can get out of the way. It doesn't need to be in focus. Color however, is more useful if in an in-focus image, so it only makes sense for color-detectors to be in the area under the focal point of the eye.
Re: Rods and Cones and Cats
I have a dim recollection that cats have alot more, er, rods? (motion detectors) than, er, cones? (color detectors).
Our color-detectors tend to be in a might tighter clump than our motion-detectors, and I gather this is generally true for organisms with color vision. This explanation I heard was that this was to give us motion-detecting peripheral vision. For detecting whether something is leaping out of a tree at you, you don't need to visually parse its details, you just need to know it's approximate trajectory and velocity so you can get out of the way. It doesn't need to be in focus. Color however, is more useful if in an in-focus image, so it only makes sense for color-detectors to be in the area under the focal point of the eye.