I think Oakleaf has it right.

I also think freezing is a defense mechanism. I think it actually works in the woods. I have seen deer while hiking in the woods, and driven by deer that have just leaped across the road and frozen when they hit the woods, and when they freeze in the woods, they really do sort of disappear -- they blend in with trees and brush. Apparently the primitive part of their brains just hasn't caught up with this modernity thing and doesn't realize that if they freeze in the middle of the road, a) we can see them and b) the danger doesn't go away.

I think deer are beautiful.