yes but (well dogs mainly, don't know about cats) have an underdeveloped sense of sight, of course they do have a greater sense of smell....
and colour perception is rods (or is it cones? always mix up the two) in the eye, but your brain also has to be able to compute the data sent from them, which, even if we gave dogs rods, they couldn't.
but yeh, how many colours you can see doesn't really how intelligent you are.
i was just trying to indicate that our brains were far more developed than any household pets.
anyway there are more than enough dogs and cats that are put down every day - never mind being spayed - if they really were intelligent they would most likely stop having their balls cut off.