This. I'm thinking maybe there isn't "werewolves", but only a werewolf!!! Maybe the one in the pic is under the influence of Hircine's ring. Maybe the ring is a quest reward given by the wolf-man or taken from him if you kill him.
No, the ring has a specific power that affects the player.
"Additional Werewolf Transformation"
Werewolves ARE in and YOU can become one. The only downside is that it's all in third person. No first person werewolf view.