QUOTE (Regency @ May 7 2008, 01:43 PM)

I don't have the answer to your question, but I've always wondered why the ghosts we see seem to be relatively "modern", you don't see many cavemen ghosts do you? Also, animals - if they go to heaven and we can have cat and dog ghosts, why not dinosaur ghosts?
Just a personal theory, but I'll throw it out there. I've had the belief that spirits are stuck here because of some kind of emotional attachment. Either from the former living person themselves, or the people still living. What I mean is, the dead are still attached to certain people, places, things, so they "haunt" them. For whatever reason, they cling and are unable to let go yet. Or, it is us that are still clinging to our dead friend, relative, etc, so the person comes back to help us move on, in a way.
This is why I think there are few caveman ghosts, for instance. Maybe there were back in those days, but nowadays there would be nothing left for them to cling to in the living world. The caves are gone, men and women have evolved, society and civilization are not what they were accustomed to. There's no reason for them to want to be here anymore. Everyone they knew is dead.
As far as animals go...I don't think animals cling and attach themselves to the living world like people. Dogs and cats, etc are very primal in that they only really care about where their next meal is coming from. I believe they feel love as well, but I don't think they sit there wondering about death or what will happen when they die. They have little to no concept of this kind of thing. So, in effect, they don't cling to life. A pet may cling to us, for instance, and may come back to help us. Because I do believe animals can sense feelings in us. When we're excited, or mad, when we're happy, when we're sad. So, maybe the "attachment" in this case is making them come back, if only briefly, to help us get past their death.
Dinosaurs, they weren't anyone's pet. No one really loved them. And, since I don't think animals have the same kind of attachment to the world as we do, a dinosaur would have nothing to come back for.
Anyway, like I said...it's just a theory of mine. Just thought I'd throw it out there.