How is BaB computed for monsters in 3.5?

[Galloglaich]

I'm looking at the Brown Bear in the Sovelior SRD, and I notice it has 6 HD but a BaB of only 4. Is there a table to determine this ratio for Monsters as for PCs?

 

[Blackrat]

Well, for example here: Types & Subtypes :: d20srd.org

It's based on the monster type and for example Animals have 3/4 BAB progression
Infact, most of monster types have 3/4. Only few have full or ½.

 

[Galloglaich]

thanks much appreciated.