Great question!!! The answer is that even know a deer or a deer herd has never seen or smelled humans before they will still be scared to death of them. The reason for this is because a deer doesnt smell a human an think human, or smell a cow etc. and think cow, they smell a human etc. and think oh crap!! MEAT EATER!! and when they smell a cow they think no problem non MEAT EATER!! This is why Havent eaten red meat during hunting season since I was like 19 year old. For years my friends thought I was nuts!! until some of them went on a Caribou hunt and since they couldnt hunt th same day they flew in they sighted in their guns and discussed the up comming hunt and what to expect with the guide, He told them the caribou they would be hunting have never seen humans before, one of my friends got upset hearing this and asked if this hunt was going to be like shooting fish in a barrel? The guide responded far from it, another friend then asked well how do the caribou know to be scared of us if they never saw a human before and the guide replied because you are a meat eater. Needless to say my friends did not look forward to returning home an telling me what the guide said. Pike