I had hunted an area with plenty of tracks but never saw a deer. I decided to wait at a fairly hidden spot, all night if I had to, to see when the deer came out. After it became pitch black a deer snorted I'd say within 15 or 20 feet from me. I never heard it approach so the sound came without any warning whatsoever. Try as I might, I could not see that deer! Maybe it winded me, but the sound of the snort was so close and seem so focused on me that I'm sure it saw me. I felt the hair on my neck rise on that one,and realized how well deer can see in the darkest of conditions. I know it was truly dark out, and that deer was wandering around without visual impairment.