Paladin Mount and Feats

[ReD_Exorcist]

So my Paladin has recently hit level 8. I can now gain Dire Lion as a mount! What I'm wondering if how do feats work with the bonus HD for it. Does my Lion get a feat for each Bonus HD or is there a set number of HD it must have to gain a feat?
Sorry if this question makes no sense

[Frosty]

Every creature (except mindless vermin and constructs and possible mindless undead) have one feat every 3 HD (more than that if Pathfinder).

[Urpriest]

You should probably read my Monster Handbook. The upshot is that HD work just like your HD, and grant feats at the same rate yours do.