This is slightly off-topic, but... In the discussion of ferret vision, someone asked how it would be possible to *know* what a ferret saw, and stated that humans of different cultures see colors very differently. (Sorry, I forgot who it was that posted). Second point first - this is actually incorrect. This proposal has been around for awhile, but was refuted a few decades ago by Eleanor Rosch. It is true that different cultures have names for different numbers of colors, and some cultures only have names for light and dark (and everything else is referred to by saying something like "It's the same color as an **whatever**"). However, this does *not* mean that they see colors differently. In fact, humans from every culture that has ever been tested all see colors the same way - even if a culture has no term for "red", members of that culture still can pick out the best red, and its the same tint as we would choose. Any introductory text in perception or cognitive psychology should refute the old rumor that "primitive" cultures see fewer colors (and yes, the original notion was tied in with notions of primitive culture vs. European culture. For what its worth, Russian has one more color term than English - but I doubt many of us feel particularly bereft, or feel that we're missing colors others can see....) As to whether ferrets see color - the original posts were asking whether they could distinguish things that differed only in color. They weren't asking whether ferrets had some subjective impression that was parallel to our perception of color - you're right that we can't know exactly what it feels like to be a ferret. But I don't think that we have to know that in order to answer the question, "Do ferrets distinguish colors." As to how you answer it - the easiest way is simply to test whether they can tell the difference between two items that differ only in color. A second way is based on what is known about the ferrets' optical system. This involves testing the responses of individual neural cells to determine their response patterns. However, most of us probably feel that the question isn't one that is important enough to be worth examining in this manner. Does it really matter whether ferrets see color? Differences in color are really just our way of perceiving differences in the wavelengths of reflected light. But there are still differences that *we* don't see - do any of us miss them? Why should it be any different for the ferret? Sorry for the philosophical ramblings. (and I hope none of this is taken as attacking any of the previous posts, as it definately was not meant so.) -rochelle (and Shadow, Fezzik, Falstaff, Butter, and Pretty Boy Floyd, who feel sorry for us poor humans who can't distinguish each other by smell, and for the world of brialliant scents that we can't appreciate) [Posted in FML issue 1452]