Yes, he is near the Howling yellowfang "camp". He seems to wander and I've seen him crossing the bridge over the yellowfang area (area i think is named weatherway - not 100% sure though). The Loc is approx. 28.8S 41.5W
Yes, he is in a little side area in midgewater pass. I killed him and looted his tooth. I have no idea about spawn times or what makes him spawn however, as when I came back and camped the area later, he didn't appear.
although i haven't seen him myself i'm reliably informed that sawtooth is a named wolf who spawns in and around the wolf den at midgewater pass... i'm guessing you simply smash his face and he'll drop the tooth, it can be used to craft polished bloodstone rings among other things