SRD:Manufactured and Natural Weapon Fighting

Manufactured and Natural Weapon Fighting
Some creatures combine attacks with natural and manufactured weapons when they make a full attack. When they do so, the manufactured weapon attack is considered the primary attack unless the creature’s description indicates otherwise and any natural weapons the creature also uses are considered secondary natural attacks. These secondary attacks do not interfere with the primary attack as attacking with an off-hand weapon does, but they take the usual –5 penalty (or –2 with the Multiattack feat) for such attacks, even if the natural weapon used is normally the creature’s primary natural weapon.