BullMastiff Temperament The Bullmastiff has a docile, calm and independent temperament. It is a devoted dog and loves human attention. It is always alert, reliable, observant and protective which makes it a perfect watchdog. They are not known for excessive barking but bark with a cause. This dog is very reserved unless aggravated. It is tolerant with children and it is also very affectionate. However, the bullmastiff is an imposing dog and therefore you should be firm when handling it.