An English breed, the Bullmastiff was a result of crossing old Bulldogs and Mastiffs to create an excellent guard to protect against poachers and other intruders. Activity level varies greatly among individual dogs, some are complete couch potatoes, and others are very athletic. Most are moderate energy, and are still working dogs. As with all mastiff and bull breeds, they may be dog selective or not want anything to do with dogs of the same sex. 100 - 130 lbs. #Bullmastiff #mastiff #large #dog