How much scent can deer really detect?

We all know that stalking into the wind helps us get closer to the deer, but I just wonder how careful we, as stalkers, need to be when disguising our scent?

JELEN DEER SERVICES replies: The average modern human has around 5 million olfactory receptors in their olfactory epithelium layer. In contrast, and a fact that is often quoted, a dog has around 220 million olfactory receptors. But a deer – whose very life depends on its ability to detect danger – has over 295 million olfactory receptors, allowing it to detect the scent of predators over a mile away in the right conditions, but certainly over several hundred metres. Suffice to say that keeping your scent to a minimum and staying downwind of your target will certainly help your chances of a successful stalk.