NO! I am a bullmastiff owner and they are known to be very gentle and docile. They are prized for their protectivness of their owner and their owner’s property. I have read many accounts of bullies putting themselves between owner and threat. Just like any breed, there can be vicious dogs. My uncle had a Great Pyramese put down a year ago for biting a neighbor kid. He never showed any agression before that.
Our Sampson was as sweet as can be with our son. The only thing we ever worried about was that Sampson did not know his size. He thought he was a lap dog. A 135 pound lap dog.
She was a very sweet dog, but could be particularly nasty when it came to stray cats invading our yard. Yet, when we brought a stray cat in and she had kittens, she became best buds with one of the kittens.
I think a lot of an animals behavior has to do with the owner. Not that I’m saying that the owners are always to blame for what the animal does. I do think that it has something to do with the environment that the pet lives in.
My grandaughter has one of these and a 1 yr old son. Oh my! He is still a puppy around 5 monthes old but he is already huge.