Some have suggested that horses can feel you moving before they can see you. The suggestion has been that they sense subsonic vibrations in the air and ground, as some other creatures as diverse as fish and elephants do. Whether it is that, or whatever field we might call aura, who knows? Maybe both? Whatever the case, they do have an acute and facinating interplay of senses.
You are right about those of us who live in modern luxury failing to use senses. We really don't need them, so they atrophy, but they are there. As a teenager, I was visiting my grandparents one Christmas at their lodge in the forest in western Illinois (about 40 miles from Moline). An old (to me then) farmer from across the road stopped in to wish them a Merry Christmas. He was intelligent, but uneducated and a communications challenge as he had been born nearly deaf and had recieved no special training. He and I were on good terms, so he invited me to go with him that night when he hunted racoons. When he swung by to pick me up I noted with surprise that he had no dog, and only a .22 rifle. As we walked through the patchy snow, I noted that he was not looking for tracks. He was just looking around and breathing deeply. Suddenly he stopped and told me there was a racoon nearby. He looked around and smelled some more, for that is what he was doing, then shined a light into a tree and there was a racoon.
He tracked by scent, as the Indians are said to have done. I, in the mean time, was just out for a walk. I could have passed a dozen 'coons and never been the wiser.
What a great "real life tale", Joe. If you'll look in your Members Only Archives disk (or if you don't have that, then the 2001 "Inner Horseman" disk if you received that in the past 6 mos. where we put the old MO Archives into the 2001 disk from there on out) -- there's a tale in there about a guy who gets lost with a companion on foot, in the Yukon, 100 years ago, in a blinding snowstorm. The companion leads him back to camp -- but only when allowed (or not blocked) from using some 'special' orienting sense. This sense probably wasn't smell in this case -- and I do not know what it was. Neither am I able to analyze what the horse's special senses are, but there is a great deal of evidence to indicate that both humans and horses have senses other than the "normal" five. -- Dr. Deb