I know this is irrelevant as it's to deers but I was watching some show that explained that deers are blind in human terms. They can hear very well and smell very well. When a deer perks it's head up, it slaps it's foot on the ground to see if anything jumps and also it's to get the other deers attention in the area as it's showing them that there is something it doesn't like in the area. Then once the white tail goes up, it's the sign to head out. I don't hunt so I found this to be pretty neat.
Also you know that a buck makes a doe cross the road first? I did not know this either until my dad told me yesterday.