James McMurray said:
Where does the FAQ allow that? The answer I quoted would specificallt disallow the tiger from using unarmed attacks because it isn't a creature that is "normally is allowed to make both weapon attacks and natural weapon attacks as part of the same full attack routine."
Any creature can make an unarmed strike, usually for nonlethal damage. Some (like monks) are better at it than others. Unarmed strike is listed as a simple weapon in the PH.
FAQ
===
Can a monk who has natural weapon attacks (such as a
centaur monk) attack unarmed and still use his natural
weapons? For example, let’s say he’s a 4th-level monk. Can
he use a flurry of blows and attack at +5/+5/+0 unarmed
(plus other bonuses) and then at +0/+0 for 2 hooves?
If the creature normally is allowed to make both weapon
attacks and natural weapon attacks as part of the same full
attack routine, the monk can do the same (making unarmed
strikes in place of weapon attacks). Since a centaur can make
two hoof attacks in addition to his longsword attack, a centaur
monk can make two hoof attacks in addition to his unarmed
strike attack (or attacks, depending on his base attack bonus).
The monk can’t use his natural weapon attacks as part of a
flurry of blows, but he can make natural weapon attacks in
addition to his flurry. Such attacks suffer the same –2 penalty
as the monk’s flurry attacks in addition to the normal –5
penalty for secondary natural attacks.
An 4th-level centaur monk has a base attack bonus of +7
(+4 from his 4 monstrous humanoid Hit Dice, and +3 from his
8 monk levels). If he performs a flurry of blows, he makes
three unarmed strikes, at +5/+5/+0. He can add two hoof
attacks at –2/–2 (–5 as secondary weapons, and –2 from the
flurry).
===
Think about how it works for an out-of-the-box harpy, BAB +7, Str 10:
Full Attack: Club +7/+2 melee (1d6) and 2 claws +2 melee (1d3)
If the harpy used unarmed strike instead, it would be:
Full Attack: Unarmed strike +7/+2 melee (1d3*) and 2 claws +2 melee (1d3)
* Nonlethal, provokes attacks of opportunity
This is normally not an advantage for the harpy. But consider a really big dragon. It could use unarmed strike, taking advantage of its high BAB and strength, with the disadvantage that it treats all of its natural weapons as secondary (-5 attack and 1/2 Str bonus on damage).