If a puppy grows up in a household where there is an older, weaker dog or a weaker sibling, the dog may acquire an inflated idea about his own capabilities. If the other dog or puppy allows him to jump on them, play whenever he wants, and really sink his teeth in without telling him off, the puppy will learn to play in this way and enjoy it. This may also happen if a puppy is taken to a socialization classes and allowed to play for a long time in an uncontrolled way.

However, when the puppy reaches adolescence and he tries to play similar game with other dogs, he is likely to find that other dog may not tolerate this behavior and they will become aggresive. Such encounter teaches the dog bully to get in there first to make sure he overpowers his opponent.

When the bullying dog is on the lead and sees another dog, he will keep still, give direct eye contact and assume a confident posture with a stiff tail with the tip wagging. If the dog bully is off lead, the dog bully will go straight up to the other dog into aggression. If there is no submission from the other dog, there may be an attack between the bullying dog and other dog bully. Strong willied dogs with high play or activity drive are most likely to develop dog bully behavior, particularly if the dog bully has not met many other dogs other than the ones they grow up with. The bull breeds bodies which are relatively insensitive to pain, are also most likely to develop dog bully behavior, in other words, a bullying dog.

It is difficult to turn an aggressive bullying dog around and help should be sought from an experienced pet behavior counsellor. Until then, the dog bully should be kept on a lead and exercised in a safe area away from other dogs. The solution lies in teaching the dog bully to enjoy playing vigorous but gentle games with human rather than other dogs. This is not easy as the dog bully get enjoyment from bullying other dogs and playing rough game.