Four important things all new puppy owners need to know about preventing reactivity.

cute puppy
Picture of Dr. Else Verbeek
Dr. Else Verbeek

Dog behaviour scientist and consultant.

Does your dog bark, lunge or growl at other dogs when you take her out on a walk? This is a very common problem and it seems to be one of the main reasons that dog owners look for professional help. So if the thought of taking your dog for a walk in the park freaks you out, you’re definitely not alone.

Image by pasja1000 from Pixabay

The problem with these type of reactive behaviours is that it can lead to aggressive interactions. Aggressive interactions are obviously a risk for people and other dogs because dog bites can cause serious injury. But aggressive behaviours also pose a risk to the aggressor dog itself, because many of these dogs end up being relinquished to shelters and may even be euthanised.   

It is important to understand why your dog shows aggressive behaviour so that you can prevent bites

Often, these problematic behaviours already start early on. Maybe you’ve just gotten a cute little puppy who just gets a little too excited when you play with her? Should you worry about play-aggression?

In this post I will discuss four important things you need to know about preventing your puppy from developing aggressive-reactivity towards other dogs:

  1. How to know the difference between play and aggression

  2. How to manage or stop dogs from aggressive play

  3. How to prevent your puppy from developing reactivity towards other dogs

  4. How to identify misdirected play-aggression

For more information about what NOT to do when you have a dog that shows aggressive behaviours, see also here.

1. How to tell the difference between agonistic-aggression and play-aggression

A first question to ask: what is actually normal behaviour and when should you worry about aggression? Aggression is a form of communication and a normal and natural behaviour for dogs. But there are different types of aggression and they have a different underlying cause and need a different approach.

Aggressive behaviours are part of the natural behavioural repertoire of dogs.

In play-aggression, dogs will growl and bare their teeth during a game. Agonistic-aggression, on the other hand, is not playful and requires careful management. Given the risks of agonistic-aggression, it is wise to consult a professional to determine the cause of aggression and come up with a behavioural modification plan.

If your dog is showing play-aggression, her behaviour is triggered by the excitement of the game and the movement of the person or toys involved in the game. Play-aggression is therefore driven by strong motivations and positive emotions.

How do you recognize play-aggression? A very typical element of play is the play-bow. This does not occur when a dog displays agonistic-aggression. Also, the absence of threatening body postures is typical of play behaviour.

Learning how to read dog body language is critical in knowing the difference between play- and agonistic-aggression

Here is an example of normal play behaviour in puppies. Do you see the frequent play bows?

And here is an example of more rude puppy play. These puppies are not respecting each others’ signals!

2. How to manage play-aggression

Play-aggression is a normal behaviour that dogs also use when playing with each other. It is often observed in puppies that have not yet learned the rules of the game, but can even be seen in older dogs. When dogs bite each other too hard, the other dog will not want to continue the play. This then teaches the dog that they should take it easy.

If your puppy is showing play-biting, simply stop the game and walk away

Do NOT punish the puppy for this behaviour, because it can increase arousal even further and escalate the biting behaviour.

Image by lindsrw from Pixabay

It is important to find out in what situations your puppy shows play-aggression. An example is when playing with kids, because this can be highly arousing. Always monitor closely and prevent an over-enthusiastic puppy from playing wild games with kids. Keep play sessions brief or maybe replace them with a walk. 

It can also help to stimulate play in a more controlled environment. This can be done with the use of a training game, a toy, or hide-and-seek game where the puppy has to look for his toy.

Teach your puppy to stop play-biting on command. You can do this by giving a clear command when her behaviour is getting our of control. For example, by saying ‘enough’ and stopping the play. The enough should be loud enough so that the pup backs away, but not so loud that she gets scared. If the pup stops the play, you can then reward the ‘good behaviour’ with a treat. When you repeat this over time, the pup will eventually learn to stop biting when she hears the ‘enough’ command.

Consistency is key here, and all family members should train the ‘enough’ command. As with all dog training, the timing of the commands and reward are really important. So if you’re a new dog owner, make sure you enrol in a puppy class to learn dog training skills and to socialize your puppy.

3. How to prevent your puppy from developing reactivity towards other dogs

It is very important that you give the correct response to your dogs behaviour. Many owners complain that their dog reacts aggressively to other dogs when going for a walk. What they don’t realize is that they may have caused this behaviour themselves by misinterpreting their dogs playful and curious behaviour towards other dogs.

Misinterpreting dog behaviour can lead to behavioural problems

Here’s an example. You’re taking your puppy out for a walk and there is another dog nearby. Your puppy becomes energetic and wants to move towards the other dog. You’re not sure about your puppy’s intention and you may be worried that he may growl, or even bite, the other dog. Therefore, you may jerk on the lead, which you may have seen on TV as an appropriate way to ‘correct’ your puppy’s unwanted behaviour, see also this post. Or you may scold your puppy, or simply pull him closer to you because you do not want to to get closer to the unfamiliar dog.

You may be successful in stopping your puppy from approaching unfamiliar dogs in this way. But what you may not realize is that you may be – unintentionally – teaching you puppy to associate an unfamiliar dog with a punishment.

Clker-Free-Vector-Images from Pixabay

The next time you take your dog for a walk, he may begin to anticipate the jerk on the lead when you meet an unfamiliar dog. The jerk (or scold or whatever you’re using) is a negative experience and something the puppy wants to avoid. This type of punishment can later on become a conditioned cue for punishment, which the dog then learns to associate with play behaviour directed towards another dog. 

In this way, you will create a dog that becomes fearful when seeing other dogs and you dog may start to react, or even show aggressive behaviour, when meeting other dogs. Then you will have a real problem.

Inappropriate correction of your puppy’s normal curiosity towards unfamiliar dogs can cause fear or aggression towards unfamiliar dogs

Of course, there are many other potential causes for dog or leash reactivity, and if you struggle with these issues, please make sure to contact a professional.

4. How to identify misdirected play-aggression.


A dog that has been unintentionally taught to react to other dogs will show mixed messages. He may show a play-bow because of the underlying play motivation. But at the same time, he may show threatening body postures because of the conditioned fear when meeting unfamiliar dogs.

If you suspect that your dogs reactivity towards other dogs may be caused by a conditioned fear towards unfamiliar dogs (and you observe play bows together with threats), it is best to consult a professional. It is very important to ‘unlearn’ that unfamiliar dogs are something scary and lead to a punishment. Instead, a professional will work on teaching your dog that other dogs can actually be fun to play with. 


Canine and feline behavioural medicine. 

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Dr Else Verbeek en witte hond