Slaverjaw

Slaverjaw is a level 49 rare red hyena that can be found in southern Tanaris, just north of the Southmoon Ruins. He has only one spawn location and he does not patrol away from it; specifically he spawns right in the middle of several very large bones sticking out of the sand. I have indicated his spawn location in red on the map below. 

He drops the typical green item and a fairly decent amount of experience for leveling characters.

He is also desirable as a hunter pet for mid-level hunters as he is the only tamable red hyena under level 82. The only other tamable red hyenas in the game are the level 82-83 Bloodsnarl Hyenas in Uldum. There are also hyenas with this exact same skin color in Western Plaguelands (Scarlet Hounds), but they are not tamable.

Slaverjaw can be found with NPCScan, but it isn't really necessary as he doesn't move from the location that he spawns at. If you do choose to add it, his NPCScan ID is 39185.

I currently have no idea as to what his spawn timer may be, but I did find him up the second time I came by looking for him. My guess is that it isn't very long, maybe 1-2 hours tops.