These are usually innate traits that come with the personality package. (educationworld.com)
Abuse does not account for an animals innate traits. (2ndchance.info)
Its bad reputation dates back to the days when these dogs were used for pit fighting, and while it's true that they can be extremely dangerous when bred and taught to be vicious, violence and ferocity are not innate traits common to this breed. (puppy-training-solutions.com)