I just noticed, our companions are much smaller than NPC's who they resemble. I was on one of my characters who is in cool ranch. I have the bison champion, Thunder Hoof and I was in the temple in the bison village. There was another bison in their, he looked exactly like Thunder Hood but was twice as big. Are companions smaller so they fit better on individual spots on battlefields? I can't really think of any other reason that a companion would be way smaller than the NPC character they resemble.

~Bloody Wolf Freeman~