I am extrapolating from experiences with a tibetan mastiff and a bull terrier. I think dogs in this family are less temperamental and less snappy.They do have a lot of aggression for other dogs or animals of similar size. But a lot depends on how they were trained. A poorly trained pitbulls can be verydangerous. But they are extremely obedient even if it comes to following orders when they are in pain. I think this is the reason they are the preferred breed for dog-fighting. There a participant is disqualified if it continues to attack after a round has ended. I am sure that trait was bred in.
