Vore (or "voraphilia") is a very strange "fetish", or more exactly an ensemble of fetishes and kinks, the composition of this ensemble varying largely from one voraphile (or "vorarephile", or "vore") to another.
There is however a basic definition and common ground which most (if not all) vores will agree with:
From there, we can already split the vore acts into two main categories:
One important thing in the vore definition I propose, is that the prey must stay alive and conscious while it is devoured (or at least for the longest possible time). Make it a dead prey being devoured, and vore becomes mere cannibalism, which is another and different kind of "fetish", in my humble opinion... Though, there is a thin border that some vores would easily cross there. For example, some vore scenes will involve cooking; in my opinion, they are still vore scenes when the prey stays alive throughout the cooking process and is still conscious while devoured, as opposed to cannibalism where the prey is killed before or while cooked...
As for what are the preds and preys, you may find any combination of the following:
What are the various fetishes/kinks that are involved in vore ?
Here again, it is only a proposal, and some of the voraphiles will probably find more fetishes/kinks to add to this list (given in no particular order):
Is vore a sexual fetish ?
That's a tough question... Most voraphiles (rough estimation: 80%) will reply by "yes, of course !", while the others will reply by "Hell, no !"...
Fact is that this "fetish" (reminder of the definition of fetish: "excessive or irrational devotion to some activity") is often deeply rooted in early childhood (most vores will admit always having had this fascination, even though they didn't know it was called "voraphilia").
But vore is also deeply rooted in any living being (the relation between predators and preys defines most of the behaviours of any living being, and the fact that humans got very few predators nowadays (but for themselves !) doesn't prevent their instinct to come into play when they witness or think about a predation act).
Add to this the fact that vore is everywhere: Do you remember about all those stories, tales (Perrault's for example) and fables (e.g. La Fontaine's), all of them full of monsters, dragons, ogres and wild animals devouring people, and that were told to you when you were a little child ?... Think about how many fantasy/sci-fi/horror movies include vore scenes... Or how much you are fascinated when watching wild life documentaries where big lions or tigers devour helpless and innocent little gazelles...
My interpretation is therefore that, basically, voraphilia is not a sexual fetish, but that, in most cases, it becomes one at puberty, because of all the other sexual fetishes it may stimulate or induce... Yet, for 20% of the vores or so (and I'm one of them), vore is not and will never be something they will sexually fantasize about... It's all about life and death, our relation to them, and about our place in the food chain...