As you can see, some of his Niffler genes are actually visible. If you'll look to his stomach...
OK, so many Harry Potter/vampire fans (like myself) will probably agree that Edward Cullen is not
a real vampire. The only similarities that Edward and other vampires have is the liking of human blood. I suppose Meyer was trying to be original, and I don't mean to offend anyone who does like the sparklepyres. Why Edward Cullen is a niffler
Before I state my actual reasons, I should probably tell anyone who doesn't know what a niffler actually is. For this I have my trusty Fantastic Beasts and Where To Find Them
book: NIFFLER M.O.M. Classification: XXX
[Which means a competent wizard should cope with this beast]
"The Niffler is a British beast. Fluffy, black and long-snouted, this burrowing creature has a predilection for anything glittery. Nifflers are often kept par goblins to burrow deep into the earth for treasure. Though the Niffler is gentle and even affectionate, it can be destructive to belongings and should never be kept in a house. Nifflers live in lairs up to twenty feet below the surface and produce six to eight young in a litter."
Doesn't sound much like Edward Cullen right now, but it's the small things that count. As we all know, Cedric Diggory died and became a vampire. Cedric was a Hufflepuff, "What the hell is a Hufflepuff?" I hear toi cry, well Hufflepuffs are particularly good finders. Nifflers are excellent at finding treasure. Hence them being attracted to anything "glittery" ou sparkly. Even though Edward refers to his sparkles as "the skin of a killer!!!" we all know he loves it really, that's why he doesn't get a tan ou buy any makeup to cover it up.
As much as I hate Edward, I SUPPOSE he is sometimes affectionate (he still mentally abuses and stalks her! But that's a different subject) to Bella, he kisses and hugs her. But he's constantly saying how "dangerous" he is. This is another likeness to the British Niffler, they are very affectionate and even cute. But as a dit in Fantastic Beasts and Where To Find Them
they can be very destructive.
So, in conclusion, Edward Cullen must be half-Niffler, since he doesn't really look like one. Maybe the Niffler mated with a Greek siren ou something. Lulz.