Anal vore (AV for short) combines the pleasure of anal stimulation and rectal 'fullness' with the motivations and pleasure of vore, with a healthy dollop of humiliation owing to the reputation of this orifice.

Although the predator loses the experience of tasting their prey by opting to use the backdoor, they can glean more pleasure from the penetration and (anatomically incorrect but convenient) backwards-peristalsis that serves as 'swallowing.'  Although the intestines themselves lack the sensitivity and pain receptors of the throat, this reality is also usually discarded, and the predator feels every inch of their prey's journey through the large and small intestine.  Often the prey is deposited in the stomach and digested normally, but some predators will choose to ignore realistic anatomy and digest/absorb prey within the intestines, ignoring the stomach entirely.  The anus may also be seen as an 'easier' orifice to use to consume prey, given that it's capable of stretching much further than a creature's jaws/throat would allow.

For the prey, anal vore can be attractive because there are no threatening teeth in the anus, guaranteeing they'll be ingested whole.  Willing prey may enjoy the extra stimulation their bodies provide the predator on their way inside.  The intestines are longer than the throat, so they provide a slower, lengthier swallowing process, both increasing the suspense of the experience and extending the pleasure gleaned from sliding through a snug fleshy tube.

There's also the messy aspect to anal vore.  Even if the scene doesn't involve scat, it may include extensive lubrication to help the prey inside, and natural lubricating mucus inside the bowels.  When scat is involved, it might take the form of a bowel movement before ingesting the prey (to make room and to show the prey what's about to happen to him/her/it) or intentionally retaining waste and forcing the prey into and/or through it.  Some prey may be converted directly to waste in the bowels without anything approaching accurate digestion.

Humiliation and degradation are both obviously easy to work into an anal vore scene, though they can be divorced from the act with the right attitudes and preparation.  There is no more humiliating way to be stuffed into someone's body than through the anus.  There is no worse-smelling (at least potentially) orifice, none regarded as dirtier, and no other opening universally regarded as unclean as the anus.  To be condemned to die, not just painfully in the depths of a predator, but to be shoved in the wrong end just adds insult to injury.

Anal vore is common in macro/micro vore artwork and stories, and pieces that depict a small furry bound to a large one's penis, poised to be shoved up another large fur's ass are surprisingly common.

Anal vore is on the rise in popularity, both in terms of inclusion in artwork/stories and a preference for it among vore roleplayers.

[There are as of yet no authoritative publications from academics on the subject of vore as we know it, only on the loosely-related subject of cannibalism, so I rely on my identity as a vore fetishist for over a decade, author of many erotic vore stories, and frequent vore-scene roleplayer to lend authority to my definitions.]