At 10:06 AM 8/6/04, Robert J. Chassell wrote:
Even though horses may not see colors as such, individual horses have a desire for certain colors. Perhaps they really do see colors
I don't know if any studies have been done showing whether horses see colors at all, but the popular idea of dogs being "color blind" meaning that they only see shades of grey is incorrect. They have two different types of color-sensitive cones, whereas humans with normal color vision have three. In those humans with red-green color blindness (the most common type), one type of cone fails to develop properly, so certain colors � most notably pure red and pure green, hence the name � look alike. (That is why the lights in traffic signals are actually sort of a red-orange and blue-green, so they appear different to those with this condition.) Cats have at least two types of cone and may have all three, so they may see as many colors as we do. However, the number of cones per unit area of the retina is significantly less than in the human retina, so cats probably see colors as rather pale and washed out. (No one has yet figured out how to read the mind of a cat or a dog and see exactly what they are seeing, so we have to rely on tests that show how well the cat or dog responds to different colors to determine if the animal can see them. And as anyone who lives with one can attest, it is not always possible to tell with certainty what a dog is trying to tell you, and the only thing cats say is "Feed me!") Interestingly, some types of birds have five types of cone cells, suggesting that they can see colors we can't.
-- Ronn! :)
"Earth is the cradle of humanity, but one cannot remain in the cradle forever." -- Konstantin E. Tsiolkovskiy
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