Parry and natural weapons rules question

Can a player use a rap on to parry an attack with a natural weapon? For example guy with sword is attacked by a wolf. Does guy get to parry a bite attack?

I would expect so.
We have always played that you can parry any melee attack, except stuff like fire or energy attacks, you're best just dodging those ;D.

I also used to double the base chance for Rapiers if using them for parrying weapons of a similar size and make (not attacking). So they got this bonus versus other one handed swords, but I actually used that bonus as a negative modifier when used against bludgeoning weapons.That's just my house rule though.

I see no reason why you can't parry a melee attack from a creature's natural weapon.

I have always ruled that you can parry a natural weapon with an artificial weapon. It also works vice versa, within limits determined by common sense - difficult to parry things with a bite attack, for example. But it's perfectly possible to deflect a weapon using only your arms or legs. Remember that a parry doesn't necessarily have to go for the weapon, for example, knife attack blocks normally target the attacker's arm or other body locations rather than the knife itself.