What Is a Bully Dog?

Boston terriers, American pit bull terriers, Staffordshire terriers, Staffordshire bull terriers, boxers, bullmastiffs and any combination thereof fall under the umbrella of bully dogs. Although vastly different, these breeds do share a number of traits, including large jaws, stocky bodies and short hair.

Bully breeds descended from a now a extinct breed called the molosser. The molosser was a large, powerful dog used for protection and guarding in ancient Greece. The various bully breeds we know and love today all display physical and character similarities to this breed, to varying degrees depending on the other breeds in their ancestry. Bully breeds were typically used for guarding livestock.

The size range among bully dogs is great. Boston terriers typically grow to around 25 pounds, while bullmastiffs typically grow to around 130 pounds. Crossbreeds and mixed breeds can be anything in between but are rarely outside of this range.

Bully dogs are typically robust, with large chests relative to their height, stocky bodies, short coats and big heads. They display a range of diverse physical characteristics, too. For example, Boston terriers have large, erect ears; bullmastiffs have loose, wrinkly skin around the face; and bulldogs and boxers have distinctive undershot jaws.

Bully breeds are typically loving, protective, inquisitive, gentle and a little clownish. Due to the sheer number of generations that have passed since these breeds were established, they are perfectly suited to the domestic environment.

If you’ve ever met a bulldog, pit bull terrier or boxer, you’ll be familiar with their loving, playful and fun personalities. Typically, bull breeds show remarkable tolerance to children and won’t flinch or become grouchy at the presence of an overenthusiastic playmate. That's a very good reason why bully breeds are popular pets. However, there are some important differences to note: For example, a pit bull is watchful and reserved, preferring to treat strangers with caution until he is confident they don’t pose a threat to his family. Bulldogs are more curious and are more likely to embrace a stranger. Boxers are alert and active, bullmastiffs much more sedate.

Unfortunately, due to their formidable appearance, size and strength, some bully breeds such as pit bulls and bullmastiffs are attractive to those who use dogs for intimidation and personal protection. If badly managed and trained, any dog can be aggressive ... but due to the size of some bully dogs, the risks to people can be more pronounced. Notoriety has cast a shadow on some bully breeds. The American Society for the Prevention of Cruelty to Animals campaigns against media bias toward bully breeds.