Dogs bark, growl and tussle when playing normally, which makes it challenging for you to tell when Rover's gone too far. Observe your pup at the dog park or in play with people to tell aggressive play behavior from normal behavior. Treat aggressive behavior yourself or with a behavioral specialist.
People Play
While mouthing and nipping are normal puppy behaviors, they're not traits you want in an adult dog who can do damage with those teeth. Short, high-pitched growls are a natural part of doggie playtime behavior, so don't be concerned. Signs of aggressive play with people include snarling, snapping, showing his teeth, lunging at you and biting you. Rover's stiff body language and deep growls could signal a bite if you don't back off.
Doggie Play
Some amount of rumbling is natural when dogs play together, including tackling, fighting, play biting and wrestling. When playing, dogs tend to use bouncy movements and initiative play by bowing with their front legs low and rear in the air. Signs of aggressive doggie play including growling, snarling, biting and lunging. The "growl rule" holds here, too: Short, high-pitched growls signify Rover's happy, while low, long growls spell trouble.
Tips
It's better to teach your dog how to play gently than not play at all. Avoid wagging or dangling fingers in front of your dog's mouth, jerking your hands away from Rover and making other hasty movement. He might think you're trying to play. If Rover gets too mouthy during play, do not hit or shake him as this can cause more aggression.
When to Call a Pro
If your dog plays aggressively with you or with dogs, a canine behavioral trainer can help redirect his aggression. Consider calling if you cannot curb too-rough play behavior after trying, if your dog needs to be physically separated from other dogs when you play or if he bites you.
References
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