I believe all animals have a 6th sense, it' s called instinct. Us humans have it, but it has been dulled by society. Animals rely on it much more than we do, so their instincts remain sharp.

Have you ever had that feeling where you know you' re being watched, then you look and a deer or other animal is staring at you? Animals are much more in tune with this " sense" than we are, and old mature bucks (and does too) have a very well-developed instinct. In a way I guess it could be considered ESP. This is just my theory. I can' t prove it, but I do believe it.