Originally posted by Zep Tepi:

Deer will spook if you aren't behind them. They have a cone of sight ahead of them.

well aware of this. this is why when i'm behind them in sneak mode and they spook i assumed it was due to wind direction. Deer in this spook on a boar fart though so it was probably something random. But I think after hundreds of hours in game i've figured out deer spook if they see you thanks lol.