deer see the colors differently than we do
so what appears orange to the human eye appears as gray to them
quote:
Deer are essentially red-green color blind like some humans. Their color vision is limited to the short [blue] and middle [green] wavelength colors. As a result, deer likely can distinguish blue from red, but not green from red, or orange from red."
Murphy explained that a deer probably perceives a hunter's blaze orange coat as neutral gray, which, if color were the only visual clue, might always blend in well with natural backgrounds. But the ultra-violet radiance of clothing can "give it away" in a deer's eye, even if color does not.
Read more:
http://www.post-gazette.com/pg/09326...#ixzz14bEcP4Xj