The American Bull Mastiff is not a pure breed. They are mixtures between an Alaunt type German Mastiff and American Bulldog or White English Bulldog. This breed is gritty like bandogs, and greatly resembling the Boer Boel of South Africa, which themselves were developed mainly from German and Dutch Alaunt type bulldogs and Mastiffs. Various Bull and Mastiff breeds were imported into North America from various countries. Such dogs have always been used in guarding farms and controlling livestock. Various types developed in various locations. The American Bull Mastiff represents one of these variations.
The American Bull Mastiff is only registered with the BBC.