Sorry, maybe my search-fu is bad, but I can't see where this question has been addressed.
Monster has bite, 2 claws. If a pc triggers an attack of opportunity,(monster is chewing on friend and is trying to get behind to flank but fails) which attack can the monster use to resolve? A bite is easy enough, but this is a dumb critter who is already snacking on one downed pc, I figure it's more likely to lash out with the claw. As the attacks are listed, bite, 2 claws, but it's just an attack of opportunity, would that just be one claw attack, or does it get both, (but not the bite obviously as that would be a full attack action for all three)?
The monster has 3 separate attacks, but the stat block lists duplicate attacks together to save room. It has one bite, a left claw, and a right claw (which are listed together as 2 claws, each with the same to hit/damage profile).
When taking a standard attack action, or performing an AOO, or dealing one natural weapon's worth of damage for free when maintaining a grapple, etc, the monster can use its bite, its left claw, or its right claw.
When taking a full attack action, it can use its bite and both claws for three to-hit rolls.
Damanta, MurphysParadox, thank you very much!
I like to think that nature "equips" every creature to use its very best option for survival. Always. I also like to think that this term "nature" applies even in a fantasy game with many creatures that are very unnatural.
In other words, even an owlbear will use its BEST attack when it makes an attack.
All of a creature's melee attack forms are available for AoOs, but it will always use the most effective attack form. As an extreme example, if a T-Rex is snacking on a downed brachiosaurus when some nosy raptor come wandering by, the T-Rex will stop snacking long enough to BITE that nosy raptor. This would also be true for a lion snacking on a downed antelope when a nosy hyena wanders by. Or for any other creature - if that creature's BEST attack is a bite, it will naturally use that bite whenever it feels the need to make an attack at anything.
The exception, of course, is for creatures whose bites are less effective than their claws - such creatures will naturally use a claw to make an AoO. Etcetera for creatures with some other form of attack.
Interesting follow on question:
Let's say the T-Rex has bite with the grab ability and currently has a brachiosaurus in a grab and is currently biting on him...and the raptor flies by and provokes.
A natural consequence would be the T-Rex would have to loose the grab and then would be required to re-grab on the next round.
By raw, does this follow?