Well hunting camo is meant (as stated earlier) to fool animals that see in black and white, which is why hunters can get away with orange too. Hunting camo doesn't exactly have a whole lot of research going into it. It's really just a print of some trees
It is good for sniping though if your going to stand still, but if a see a tree running through the woods im going to look closer at it
Anyway this website can explain somewhat if you don't want to get real detailed about the sciency parts:
http://www.multicampattern.com/aboutThis is also why I believe multi camo is tops, even if it is in general $10 more
Oh and side note, yes ACU will make you stick out like a smurf in the ocean. I learned the hard way