For some reason I was thinking about these creatures again... think "blink lions" except that instead of teleporting short distances they can jump between worlds.
If one finds prey that it can't handle (or eat all of) on its own, it howls for the rest of its pack and they teleport in. If the pack can't handle the prey, but a larger force could, they all howl together... and every nearby pack teleports in.
If the collection of packs still isn't enough, well... the more of them that howl together, the wider the call goes out.
On the upside, a cleverly designed trap can sometimes kill quite a number of them by letting them call more and more Ravagers until you're finally ready to spring it. Their ability to flee into neighboring dimensions when necessary makes even this rather difficult, though.
One world eliminated a lot of them at once with a huge pile of poisoned meat... as a result, the surviving packs often won't take carrion... only meat that's still kicking.