Why does Rorkoun get Improved Grapple feat without Improved unarmed strike Prereq (it isn't a bonus feat)

[Starbuck_II]

Rorkoun located here (from Pathfinder River Run Red):
http://www.d20pfsrd.com/bestiary/monster-listings/aberrations/rorkoun

They have the feat Improved Grapple feat without Improved unarmed strike Prerequisite.

Was this a mistake or new errated rules that you don't need the Prereq anymore for the feat?

[Cheapy]

I believe that in 3.5 something akin to grab let you take Improved Grapple without IUS. Sean has a post about this. Something involving an ooze. Search his posts for grab, ooze, pseudopod, grapple. Not all at the same times.

Why do I remember that??

[blackbloodtroll]

Secret of the Ooze?

[Cheapy]

Here's the thread I was thinking of.

[JiCi]

Wasn't there something about having natural weapons being considered as having IUS?