Freud and Jung (especially Jung) wrote extensively of what monsters and mythical creatures mean in relation to our psyches. Every culture has myths about monsters and from the Epic of Gilgamesh and the myth of Hercules, to the legends of aborigines in Australia about the monsters that live in the outback, to the Twilight movies of today, there is something about the monster tale that fascinates us.
I remember my first real exposure to the monster myth. I saw Jaws when I was five years old and I have loved that movie ever since. Even now, in my thirties, I watch it about once every other year or so. Aside from being a great story, it represents something much deeper. The "unknown" lurking underneath us, ready to pounce at any moment.
The biggest draw to me and the biggest question in monster books is: Does the monster represent an actual external threat or is it a representation of our internal shadow-as Jung called it?
I couldn't possibly begin to answer this question, but I can tell you that when I was writing Savage, the monster was certainly a representation of the internal darkness in the protagonist, Nathan Beaufort. The beast and Nathan are linked; as one grows insane, so does the other. To be honest, I didn't plan to write the book that way but after finishing it and reviewing it, I could see the parallel clearly. The unconscious, especially in an art form as expressive as writing, certainly has a way of getting across what it wants to get across.
Though many literary types hold their nose up at the monster genre, they are usually unaware of its true literary merits. I have no doubt that if some of them cuddled up with Moby Dick or Jaws, they would see exactly why we need the monster genre. It teaches us something about ourselves. That, despite our veneer of civility, man can still be as savage as nature.