Also, something to be noted in this convo. the "hole closes" thing is an intrinsic property of the Swallow Whole special ability. see the following. regen has nothing to do with this particular hole closing.
Except in the case of the Tendriculos, it specifically is the creature's regeneration that closes thw hole, which makes it one of the few cases where the closure makes sense, unlike the usual claptrap about 'muscular action'.
