Dog Aggression: dog eat dog (why nice dogs do bad things)

This article by Karin Larsen Bridge , part owner of Get S.M.A.R.T. Dogs in Sydney, first appeared in Dogs Life Magazines Sept/Oct. 2002 and is reproduced with kind permission of the owner.


"DOG EAT DOG - Why nice dogs do bad things"

(Note: this article deals with the most common type of dog aggression of lunging and barking on lead at other dogs without a history of actually causing injury)

Most pet owners long for a friendly dog that plays happily with each and every dog it meets. The reality however is that many dogs act aggressively in the presence of other dogs. Aggression is a complex and emotive issue. When a dog aggresses you immediately have two problems: the canine problem where one dog may be intimidated or injured and a public relations problem where the owner of the victim is justifiably angry. The first thing you need to do is to assess just how severe your dog's aggression problem is.

Assessing dog aggression.

  • Behaviourists look at two aspects of aggression to assess the extent of a problem:

    1. Bite threshold: how quickly does your dog resort to aggressive behaviour? Would it take an unusual mix of circumstances before your dog would bite or is it an immediate reaction when he sees another dog?
    2. Bite inhibition: how hard does your dog bite? Dogs should learn to limit the power of their jaws in puppy class bite too hard and play ends.

Perhaps surprisingly, bite inhibition is more important than a high bite threshold. In other words, it is better to have a dog that snaps a lot but never injures another dog, than a dog that seldom fights but when it does the victim ends up needing treatment. Even though the snapping dog may be a social embarrassment, it is intentionally warning other dogs to keep away without making contact. This gives you the opportunity to work on the problem without putting others at risk.

  • Dogs with poor bite inhibition, whose attacks necessitate a visit to the veterinarian - have a serious aggression problem and should be seen by an animal behaviourist who will plan an individual treatment program.
  • Don't confuse 'shouting' with 'murder'. It is quite natural for dogs to occasionally communicate with hackles up, a lip curl and snap. Older dogs and bitches often put puppies and male dogs respectively in their place using just such body language. If your dog acts in this way with specific dogs without doing any harm you probably don't have a problem.

How Predictable is your dog's aggression?

The more you can predict the target of your dog's aggression and the context in which it is likely to occur, the easier it is to plan ahead and manage the situation.

Ask yourself these questions: What type of dog is the target of the aggression?

  • All dogs?
  • Particular breeds?
  • Particular sizes of dog small, large?
  • Dogs of a certain appearance length of coat, colour?
  • Males or females? Dogs that have been de-sexed?

In what context is the aggression likely to occur?

  • On leash or off leash?
  • When playing roughly?
  • Around resources such as a favourite toy or food?
  • Near you?
  • On specific territories e.g. the park, at home, local streets?

Why do dogs aggress repeatedly?

A behaviour repeats when it is rewarded. For most dogs nature provides two rewards for aggression:

  1. The scary dog moves away from your dog &/or from a resource the dog wishes to control such as a toy, food, or you.
  2. It makes the dog feel better. When a dog is stressed by the presence of another dog, a chemical bath of adrenalin and other neurotransmitters build in the brain. When the dog responds by acting aggressively the chemicals are disseminated and the dog feels physiologically better.

Your dog learns that aggression is a strategy that works and makes him feel better. A little bit of punishment on your part such as shouting 'NO!' is unlikely to be sufficient to counteract these two large rewards.

Fear is a main cause of aggression

The vast majority of aggressive attacks are caused by fearfulness and a desire to move away the scary object. The most common causes of fear aggression are:

#1. Lack of early socialization with other dogs. Dogs, who have failed to learn canine social etiquette and body language prior to sixteen weeks of age, may have problems socializing with other dogs for the rest of their lives. This is one of the main reasons puppy preschools were begun - to give puppies, during this important developmental period, the opportunity to interact with a variety of breeds, learning appropriate patterns of play. For some breeds, less genetically inclined to be social with dogs this early opportunity to learn is essential.

#2. A learned response (nurture), caused by restraint and unintentional signalling from owners. Most dogs are more aggressive on leash than off for four main reasons:

I. The owner unintentionally signals the dog to aggress through his body language and behaviour (see below).

II. Knowing the owner has signalled an attack the dog is more courageous as he is now leading his attached pack rather than fighting alone.

III. Dogs have an opposition reflex, the more you pull back the more the dog will pull in the opposite direction.

IV. Unable to flee the situation (restrained by the lead) the only other option is to fight.

Why does the dog think you are signalling an attack?

Imagine this scenario; your dog has a snap at a dog that stuck his nose in his face (an appropriate canine response to rudeness). Mortified and embarrassed at your nice dog's rudeness you jerk the lead sharply and say 'no!' Your dog finds this attitude of yours rather strange, perhaps it would be better simply to keep dogs at an arm's distance - so next time he sees a dog he gives a bit of a growl while the dog is still a few meters away. Worrying that you may have a problem developing you say 'no!' again and this time apply a harder jerk. Next time you see a dog approaching you decide to be proactive; you tighten the lead, take shorter stiffer steps and hold your breath. Your dog, who is an expert at reading body language, is now convinced that there is a problem with dogs approaching his pack of two. As you've become so tense he'd better get in there quick before this dog has a chance to attack and/or you get angry with him again.

To make matters worse owners may react to this aggression by:

  1. Reassuring the dog using a soothing or praise tone of voice 'it's alright sweetheart, that doggy isn't going to hurt us', thereby reinforcing the behaviour.
  2. Applying punishment or an angry tone of voice thereby increasing adrenalin and associating the appearance of another dog with bad things or
  3. Setting a bad example shooing the other dog away thereby convincing their dog that strange dogs are to be sent away by whatever means necessary - for a dog this means an aggressive display.

#3. Nature the role of genetics. It is worth noting that some owners seem to do everything wrong and still have a friendly, sociable dog while other caring owners who try to do everything right land up with a dog aggressive dog. Dogs are born with varying degrees of social inclination particularly to animals outside their own pack. Dogs that are more naturally fearful and reactive to their environment are more likely to resort to aggression as are dogs that like to be in charge of every situation. The best you can do is to try to understand and work with the your own dog's unique personality.

Aggression not directly related to fear:

Barrier Frustration - another type of on-leash aggression. Although many of the above factors may still apply, the main reason for this type of aggression is a frustrated desire to contact the other animal. Usually this type of aggression is seen in young, out-going, dogs that are play deprived or again lack socialization. They do not actually want to hurt the other animal but they are desperate to get to it and interact with it in some way. Unfortunately very often these dogs lack canine social skills so their advances may be met with some aggression as they bounce rudely into the personal space of the other dog. Barrier frustration can also be seen in cars or along fences when dogs are prohibited from contacting one another by a physical barrier.

Challenging behaviour -if the target of your male dog's aggression is other male dogs, then the problem is quite probably a guy thing. This behaviour is most commonly seen in young, entire males but may also be seen in some outgoing bitches. If your dog frequently engages in challenging fights where dogs are getting hurt then de-sexing is worth considering and the younger the better before fighting becomes a habit which can linger long after the hormones are gone. In the case of females de-sexing will be of no benefit.

Resource Guarding - some dogs jealously protect their valued possessions such as balls, tug toys, food bags, and that most valuable of all resources YOU! Rather than protecting you the dog is making sure he does not have to share your attention with anonymous canine freeloaders. Make sure any early signs of aggression (see below) make YOU move away - this is the last thing he wants.

Prey drive/aggression - if your dog most often targets fast moving dogs, particularly small white fluffy ones, it is quite likely he/she has a strong prey drive. This dog may be perfectly well socialized and non-aggressive with dogs in general but once it sees something that looks like a rabbit running, he shifts into a whole other world known as prey drive. Most dogs have some degree of prey drive but for those with strong, natural instincts to chase and kill, it is potentially a very serious problem. Prey elicited aggression has a strong genetic component and needs to be treated differently to other aggression problems. It is mentioned here for diagnostic reasons only.


  1. Decide the severity of your dog's aggression problem. If your dog is more of an embarrassment than a physical danger to other dogs, feel free to implement the following procedures. If your dog's aggression problem has resulted in serious injury to other dogs you will need to see a behaviour specialist for further advice.
  2. Accept responsibility for your dog's safety and the safety of other dogs.
  3. Prevent rehearsal. Many owners will suggest you let the dogs 'sort it out' or 'it will do my dog good if your dog tells him off'. While this philosophy may be acceptable for two well socialised dogs with good bite inhibition, it is not going to benefit the dog aggressive dog - it'll just be more practice and more confirmation of the belief that biting is a good strategy for removing unwanted dogs. The more your dog rehearses this strategy the more ingrained it will become. That is why it is essential not to put your dog in a position where he feels the need to aggress. You can help prevent aggressive incidents by being aware of:
  4. Use a head halter -this will greatly improve your ability to control your dog allowing you to feel more confident and relax. A head halter is NOT a muzzle however -so you need to remember that your dog will still able to inflict a bite if the other dog moves in too close.

      1. Early signs of intent to aggress - every dog will indicate to some extent a preparedness to attack. The signs may be as subtle as strong eye contact and a slight stiffening of the body to more overt signs such as raised hackles, growling or barking. By recognizing and reacting immediately to these signs by calling your dog to you or turning quickly away - you can prevent aggressive incidents from occurring. This is an essential part of re-training that requires good observational skills, concentration and timing.
      2. Your dog's critical distance or space requirement. Every dog has a distance where he does not react to another dog. Make certain your dog has enough space around him that he does not feel the need to flight or fight.

 5. Train an excellent come response or if in doubt, leave your dog on a light line to ensure that you can always successfully call him to you. Use a pleasant voice you want the dog to choose coming to you above all else. A threatening tone is only likely to make your dog hesitate and will increase adrenalin production in an already aroused dog. A friendly call off will redirect the dog into a new activity without a further adrenalin surge. Although a reliable come cannot prevent someone else's dog from running over to you, it does give you the option of putting your dog on the lead, holding him while another dog passes or if the other doglooks suitable, allowing an interaction to take place. This greatly enhances your ability to manage your dogs aggression.

6. Proactive P.R. Once your dog is on a lead you have every right to ask the other person to keep their dog a reasonable distance away. Something like: 'My dog does not like strange dogs in his face, could you please call your dog?' If the owner takes no notice, take it one step further. 'If my dog is on a lead by my side he shouldn't have to put up with your dog jumping/sniffing at him'. Point out that many dogs see over-the-top greetings as an assault and you would rather not put your dog in that situation. This puts the onus on the other owner who should be able to call their dog to them.

7. Train alternate behaviours. If you want to stop your dog focusing on dogs he doesn't like, you need to provide him with a pleasant, alternate and incompatible behaviour. Your dog cannot hold a sit stay and eat hot dogs while fighting at the same time. An even better idea is to train fun behaviours such as a roll over or shake hands. How about a game that you both enjoy? These exercises will not only improve the general control you have over your dog but will activate serotin production in your dog's brain as the cerebral cortex or thinking part of the brain takes over from the limbic system (adrenalin producing).

8. Change the association - offering your dog a special treat every time a dog approaches and stopping as soon as the dog passes is one way to change your dog's opinion about other dogs. Soon the arrival of a dog predicts a special treat and focuses the dog's attention on you rather than the dog.

9. Avoid Physical Punishment. Shouting at your dog, or jerking on the lead are adrenalin triggers that will produce an instinctive flight or fight response in your dog. Try to stay cool, calm and collected throughout the treatment process instead. This will enable your dog to engage the cerebral cortex or thinking part of his brain giving him the opportunity to acquire new more desirable behaviours.

10. Be A Dependable Alpha - being the alpha or leader of a pack has nothing to do with dominance. It has to do with the ability to provide for the welfare and safety of your pack. The less frightened, annoyed, nervous and tight leashed you are the more you will impress your dog. The impression you want to give is that nothing your dog (or any other dog) can do, will bother you, for you are quietly but decidedly in control. Remember most dogs act aggressively because it has proven to be a successful strategy for keeping other dogs away. By applying the strategies outlined above, your dog will learn that he can relax and trust in you to keep him safe.

There are no quick fixes.

There are no easy or definitive solutions to aggression. It is important to recognize that a dog that regularly acts aggressively to other dogs is not a dog you may ever be able to relax with at the dog club or park. The younger the dog the better the prognosis but in most cases the problem can be minimized but not totally eliminated. If you accept the role of cool, calm protector, you will need to carry out your duties diligently, planning ahead for every situation. Remain watchful and observant at all times ready to step in when and if your dog shows the signs of stress or fear that lead to aggression. Learn which strategies work best for your dog and apply them consistently.

Although these dogs may never win a canine congeniality award they are often extremely devoted to their owners and for one reason or another, simply prefer the company of humans to their own kind.