Sundering Natural Weapons?

[SangoProduction]

From slicing a critical muscle group to swing its tail, to slitting open the flame canal of a dragon, there are several fantastical ways of conceptually disabling enemy capabilities.

But are there mechanical ways?

[Psyren]

Called Shots (https://www.d20pfsrd.com/gamemastering/other-rules/called-shots/) allow you to damage or sever limbs if that's what you're looking for - you can find them in Ultimate Combat.

[bannondorf]

Called shots are the RAW way to knock out body parts. fun mechanic. fast and easy. however I had a friend that made a more complicated home brew version on a auto updating spread sheet (I have a copy) that took into account armor, type of skin, bone, creatures size etc. to determine amount of damage to break or remove a part. for example a medium character wearing breastplate armor with 68hp would require a slashing blow of 47 damage to cleanly remove his arm, 31 to break it (have to get through the armor then do half damage to flesh and bone).

essentially he surmised that to cleave a called bit off a monster you had to take each layer of the limb into account, hardness values are easy to come by and hp of the limbs flesh was the creatures HP / a percent of the creatures mass it accounted for. So in the case of the arm above the creature has 68hp, a arm accounts for 10% of the creatures mass, so rounded up to 7hp in flesh with a inch or so of bone in the center of that adding 5 hardness and 20hp, but before you get into that you have to slice through the arm of the armor/gauntlet which steel has hardness 10 and 10% of the suits 30hp is 5hp. after armor you have to take into account natural AC if applicable, in out case its zero but where it a dragon with scales or Minotaur with thick hide, assume at least leather, 2 hardness, or as hard as they have DR whichever is more and a appropriate amount of hp to go with it as though it where a analog material, a second suit of armor essentialy.

steel 10hard/5hp >> NAt AC (0hard/0hp) >> flesh 7hp >> bone 5hard/20hp == 47 damage

but that is very complicated, and very homebrew. definitely slows down a dramatic moment. but if you like super complex but closer to RL systems its a fun way to do it.

[Eldaran]

The Blacksmith class (http://spheresofpower.wikidot.com/blacksmith) from Spheres of Might can do it with their Thunderous Blows ability.