At first glance, one might wonder what could possibly be the reason for allowing, even encouraging, such a thing to happen. To understand how the TerriBull evolved, we have to try to find a rational motive... some justification for such a high risk endeavor.
Let's face it; just getting the Terrier to go along with it had to be a daunting task. (The first breeders have since reconsidered and will fall back on cloning from this point forward).
The Yorkie is known for having the heart of a Lion. In spite of it's dimiutive stature, they are oblivious of their small size. They are always eagar for adventure and trouble. Just try to approach a senior citizen while they're holding this neurotic little bundle of neurosis, and you will have some idea of their ferocious nature. They'd chew your arm off if it didn't take so many bites to do so. Thanks to the TerriBull breeding program, they can now do it it two bites. Is this progress or what?
As to the Bull Mastiff; just think MASSIVE! This is a breed where it's the luck of the draw as to what kind of temperment one might end up with. Some are energetic and some laid back. They can be hard headed, or mild natured. While one will be serious, another will be a funny sort of a goof ball; some will hate everbody and everything, and some will love them all. (Except for other animals, who will certainly regard any confrontation as a traumatic encounter).
The mastiff has a mind of his own and it takes a strong willed owner to convince him who is the alpha, the boss. (Which depends on the fear factor of the owner and can go either way). If you leave them alone for too long, they can be a bit destructive indoors. Turning an eight foot long couch into a pile of toothpics and cleaning rags can take place in an amazingly short time