Bullmastiffs, originally bred from English Mastiffs and English Bulldogs, were used to catch and hold down poachers in the forests of England during the 19th century. Although developed as a guard dog it has a stubborn streak which can make it difficult to train. Bullmastiffs become very attached to their family and can become overly protective.

The Bullmastiff is a loyal, loving and courageous pet. In general they are great with children but parental supervision should always be maintained. The Bullmastiff is capable of playing the clown and may accidentally knock small children over in his exuberance. They love human company and are happiest when they are with their family.

Bullmastiffs generally get on well with other pets in the family but may be less than friendly with strange dogs and other dogs of the same sex. Early socialisation, with people and other dogs, and training can help to prevent any unwanted behaviour problems.