I've read that deer smell at the molecular level. Not only can they detect odor they can differentiate it at a level our tiny noses couldn't even come close to. Lets say all human scent profiles are made up of 5 distinct molecular bases, a la our stink, we for the most part can't even smell that unless ones hygiene is non-traditional, even then it's just stinky, but deer can break down the scent into the five distinct bases, and a dog like a deer can determine the molecular density of an odor to determine direction of travel and with that the time in animal sense that is was left, that's what gives them direction, < density to > density. IMO that puts deer and humans in complete separate worlds. From here we can talk about sixth sense. Humans have a sixth sense. We've all felt it at one time or another, but we've been conditioned to disregard it, plus our senses are like a dull knife compared to the obsidian like sharpness of a deers'. Maybe it's our over sized brain that unconsciously strives to "understand", predetermining our thought pathways, always needing proof, that blocks us from being more in tune to the subtlest inputs from the physical world, thus adding to our physiological sensory impairment. Einstein says "energy can't be created or destroyed it can only be changed from one form to another". Lets say I strike a match and hold it a half an inch from my finger, I will perceive the energy that is stored in the match because of the transformation of its form from a match (read physical combinations made up of carbon and other elements) to heat and light. I can perceive it with my limited senses because I'm close to it and the chemical reaction(change of form) is intense, but when the stored energy is consumed and the match goes out the energy it created when it was burning still exists, only I can't perceive it any more, it doesn't make it gone, only gone to me. I like to think that when considering nature I can't with 100% accuracy use the terms always and never. Given the staggering number of combinations at the atomic level provided by the universe, and with my scientifically oriented thought process I must allow for the possibility that a combination exists that would allow another organism to perceive things at levels which I cannot. Evidence exists that supports this statement as true. One example is the canary in the coal-mine. It's an organism that exists that perceives things at a level that I cannot. Salmon return from the ocean to a specific estuary using the earths magnetic field as a compass then when in chemical proximity they can sense the specific make up of the stream they imprinted on as a fry. MIC DROP! BAM!!! Miracle, Magic, or Physical Perception the differentiation of these things is unimportant....unimportant I'm not sure but definitely above my pay-grade.