Puppies can play rough. Puppy play consists of chasing, pouncing, barking, growling and biting. Many pet owners mistake normal play behavior as aggression or laugh off behavior that is a warning sign for truly aggressive behavior. ... It isn't normal brain development for a puppy to do that to people or other dogs.

What causes a puppy to be mean?

Any breed can produce an aggressive puppy. Often puppy fear can become puppy aggression. Positive reinforcement, punishment-free obedience training is one way to create a well-behaved, well-mannered dog and prevent fear aggression in puppies. ... That means taking immediate and appropriate action at any sign of aggression.

What are signs of aggression in puppies?

The most common aggressive puppy behaviour warning signs include snarling, growling, mounting, snapping, nipping, lip curling, lunging, dominant body language/play, challenging stance, dead-eye stare, aggressive barking, possessiveness, and persistent biting/mouthing.