In the world there are three wolf species: The Gray Wolf, Red Wolf and Ethiopian Wolf. There are also several subspecies that are named based upon the region where they happen to be found. While there are plenty of similarities about these types of issues there are therefore enough differences to separate them. The more research that is done.
Other than hunting to eat, wolves are usually not aggressive. However, they will fight other animals and even other wolves in order to protect their pack. This is where the stories often come in of wolves being violent killers. Right now the biggest threat is to them and not to other animals or humans. The reduction of their habitat has created a great deal of hardship for the wolves.