Animals do not have a "fear" of humans. Continual fear is deleterious and the process of living would not occur if deer had this state of apprehension. Deer and other prey have an anxiety mechanism...cant think of the word for it...but its been imprinted in their DNA over years of evolution. Whether its the fear of asaber-toothed tiger, ora modern day hunter, when the (wild) animal smells you, it will act upon instinct.Fear can be useful, even when that fear is irrational.