Candidus- read masters of the wild pages 34 and most importantly page 38
except from page 38 MotW
Heading Awakened Animal
While normally a creature with such a high intelligence
isn't subject to animal friendship, an animal awakened by a
druid remains her companion as long as she treats it with
respect, as discussed above. The animal continues to
count against the druid's Hit Dice limit for animal companions.
For a time, the awakened animal can even exceed
the druid's level. (For example, an awakened dire bear suddenly
has 14 HD, but it remains with a 12th-level druid).
Until the druid once again exceeds the animal in Hit
Dice, however, she cannot gain new animal companions.
As a general rule, an awakened animal continues to
assist the druid, at least as long as she continues to include
it among her companions. When she elects to
leave that animal behind (by befriending a new one), it
soon departs. The animal remains friendly with the druid
and may assist her from time to time, but it no longer accompanies her on adventures.
so as you can see Awakened Animals can indeed be animal companions and it even temporarily allows you to exceed your HD limit per level