If you decide to take your dog to the dog park it is important to know about dog body language and how to react to bad situations. Even if you never decide to take your dog, it is still important to understand how to assess dog behavior when meeting a dog on the street.
Dogs are normally much rougher with each other than with us. That is completely appropriate as long as we can read their body language to determine if we need to intervene at any point. It is very important to understand what the term "inappropriate" means. Dog interactions are all situational. If there are two dogs that play extremely rough with each other but the situation never escalates into a fight that might be fine. However, those dogs go to a dog park and play at the same level of intensity with unknown dogs, it could escalate into a fight.
If a dog shows teeth to another dog and the other dog backs off, that is completely appropriate and there is no need for immediate concern. Keep an eye on the situation and if it happens more than a few times in a short time, then the play session should end just to proactively avoid a fight. 

Dogs show body signals to inform the other dogs that they are about to play.
Dogs only have their energy to survive and don't want to unnecessarily get injured by getting bit. They basically tell each other "I am showing signals, and I am going to jump on you and bite you, but since I am showing you these signals, don't hurt me, OK?"
Appropriate Playgroups Include
- Bouncy movements
- Relaxed body including eyes, mouth, tail, etc.
- Changes in body position. If one dog is on their back, we want to see him on top of the other dog at some point. If one dog is being chased, we want to see him chase other dogs. If one dog is biting your dog, we want to see him biting that dog, etc. If a dog is in a position for too long, than they are probably trying to escape and can't.
- Dogs paying attention to dogs that don't want to play. If a dog shows teeth or tenses up and emits signals in the "bad play" section, than other dogs should back off and play with another dog.
- Escape routes. We need our dogs to be able to run away from the activity if they want. If a dog is cornered or chased and has not way to add distance, then he may quickly start to fight to protect himself.
- Play bows. Dogs arch their backs and put their butts in the air.
- Signs that a Dog is Stressed and the Situation Might Escalate
- Tense movements.
- Full teeth, vertical teeth shows aggression, horizontal teeth shows fear. Fear can quickly turn to aggression if necessary.
- Slow tail movements, showing signs of being unsure.
- Freezing
- Air snaps. (possible neutral sign as well)
- Wide eye (you can see the whites of their eyes)
- Neutral Signs If Happen Infrequently (watch for repeated signs such as yelping)
- Vocalization. Dogs that growl or bark are not necessarily aggressive or unhappy. Some dogs do that when they are playing.
- Yelping. If a dog yelps once, pay attention and make sure that the dog is not in a situation that they can't get out of. If they are yelping continuously, end the play session and try another day.
- Air snaps. This is a warning signal or could be playful. If dogs back off, then it is not a problem.
- Relaxed-mouth mouthing. Dogs bite each other playfully. As long as the other dog is not showing stressful signs, then it is fine.
Breaking Up Fights
Damage can happen in a very short period of time, so it is important to be prepared to quickly intervene. It is very important that you think about your plan of action any time your dog is in a playgroup so you are not caught off guard. Look around your environment and choose items that you might make noise with (garbage cans, chairs, trees, etc.) if necessary. You should decide which of the following you should do. The suggestions are listed in order of severity.
Keep in mind that any time you touch a dog you should prepare to get bitten. When dogs are in a frenzy and they feel contact on any part of their body, they often spin around and bite anybody, even if you are touching your own dog. 
 

Ways to break up fights include:
- Make noise. First thing to try is running up, clapping and saying "Hey!! Stop it!! Ah! Hey! Hey! Heyyy!". This is often times enough to break up the fight. Bang garbage cans, stomp feet, and use a bicycle air horn to make noise. etc.
- Throw things at the fight. This can include toys and balls, sand, wood chips, etc.
- Spray with hose or water.
- Grab dog near waist and pull back with dog's head facing away from you and pointed down towards the ground. Good chance you will get bitten.
- Grab base of tail and pull away. Good chance you will get bitten.
- Put something in between dogs fighting, this can include a tennis racket, umbrella, your bag or purse, your arm wrapped in a jacket, etc.
- Put a jacket over the dog's head.
If your dog is uncomfortable at the park, get him out of there. If there is an aggressive dog at the park, leave. One of the challenges with a dog park situation is some people do not take responsibility for their dogs.
Another issue to keep in mind is the amount of time that you spend. Some dogs are fine at the park for 15 minutes and repeatedly get in fights after 20 minutes, for instance. If your dog starts to get uncomfortable, leave and come back another day.
