The Masti-Bull is a cross between a Bulldog and a Mastiff purebreds. They are very athletic and agile dogs. They are extremely intelligent, confident and docile. They are good with all family but need an owner who displays proper pack leader qualities. Hybrid Origin: The Mastibull is a hybrid between the American Bulldog and the Mastiff. Erroneous Alias: American Masti-bull, Masti-bull Country of Origin: Mastibulls originate in the United States of America. Original Purpose: The Mastibull is a great family companion. Breed Characteristics: Mastibulls tend to be active, playful, and outgoing. Mastibulls tend to be very courageous, fearless and loyal. Generally Mastibulls are alert, intelligent and friendly towards its immediate family but not strangers. Life Expectancy: Average life expectancy for the Mastibull is 10 - 13 years.