| Goblin_king |
"You can attempt to sunder an item held or worn by your opponent as part of an attack action in place of a melee attack. (PFRPG 201)"
Sunder is off the table against natural weapons.
But what of the Hydra? The most well known example of sundering monster "parts." If you can chop them up why not a tigers claws? I too have a sundering character and am treating natural weapons as if they were manufactured.
A hydra can be killed by severing all of its heads or slaying its body. Any attack that is not an attempt to sever a head affects the body, including area attacks or attacks that cause piercing or bludgeoning damage. To sever a head, an opponent must make a sunder attempt with a slashing weapon targeting a head. A head is considered a separate weapon with hardness 0 and hit points equal to the hydra's HD. To sever a head, an opponent must inflict enough damage to reduce the head's hit points to 0 or less. Severing a head deals damage to the hydra's body equal to the hydra's current HD. A hydra can't attack with a severed head, but takes no other penalties.