Improved Grab and grapple damage

[Stalker0]

When a creature has improved grab, they hit and do damage and possibly start a grapple. If they successful get you into a grapple do they do extra unarmed damage as is typical when a character starts a grapple?

 

[Kershek]

When a creature successfully does an improved grab, they do damage from the weapon that caused the grab. Therefore, a lion that does an improved grab would do bite damage.

 

[shilsen]

When a creature successfully does an improved grab, they do damage from the weapon that caused the grab. Therefore, a lion that does an improved grab would do bite damage.

I have to disagree. The Improved Grab description (3.5 MM, pg.310) specifically says that "a successful hold does not deal any extra damage unless the creature also has the constrict special attack".

Therefore, to use your example, a lion which hits with its bite would cause normal bite damage and then get a chance to start a grapple as a free action. If it succeeded, it would have a hold on the opponent, but would not get any extra damage. In this specific example it would get to try and rake as well, but that is a special ability and would not apply to all creatures with improved grab.