Dog Aggression – Signs, Causes and Trainings

Written by: Bojana Radulovic
This guide is designed to take you through the examples of the most common manifestations and causes of dog aggression and to suggest some training exercises or other actions that may help you solve this problem.

Dog aggression is one of the most complex behavioral issues, considering that its sources, triggers and manifestations may vary.

The term itself refers to a violent behavior towards humans or other animals, yet nowadays some owners tend to perceive other behavioral issues as an aggression, and make a wrong approach towards the problem.

This guide is designed to take you through the examples of the most common manifestations and causes of dog aggression and to suggest some training exercises or other actions that may help you solve this problem.

Aggression is an integral part of all animals’ behavior. Actions commonly interpreted as the signs of aggression are, apart from biting, also growling, teeth baring, and also snapping the jaws without actually making the contact.

Basically, aggression is the manifestation of emotions, a part of the spectrum of various behavior patterns dogs rely on in everyday life. Aggression is, therefore, present in all dogs, but what makes the difference is if it’s passive or active as the element of everyday routine.

Whether it’s only present as the awareness that the aggression is an available tool to deal with some extreme situations, or if it is a common reaction to various everyday situations is what makes the distinction between the dogs with or without aggression issues.

Aggression surfaces in situations that dog recognize as threatening. What makes the subject of dog aggression so complex is the fact that various conditions shape up dog’s perception of what is threatening and what is not.

Common places in explaining which situations dogs see as threatening are:

  • Dog’s own safety
  • Safety, taking away or well being of someone or something he cherishes dearly
  • Frustration built upon inhibition over doing something he really wants to do

What is important to keep in mind is that, although there is a difference in predisposition, there are no naturally born aggressive dogs. Aggression IS present in every dog, but causes that provoke it is what should be considered. There are also no aggressive breeds, only the ones that require specific training.

Sex of the dog is not what is crucial when it comes to aggression either. There are aggressive females as well as aggressive males. Even neutered dogs are completely capable of aggressive behavior. So what makes an aggressive dog aggressive is basically the conditions the dog lives in, influences he is being exposed to and the health condition he is in.

That is why the role of the owner is essential when it comes to raising up a happy, well socialized dog with no aggression issues. The most common mistake owners make is that they immediately react to any display of aggression by punishing the dog. Aggression is caused by feeling threatened, and by physically punishing the dog that already feels endangered, you create a whole new level to it.

Aggression issues are not to be handled neither roughly nor to be ignored. These complex problems are best to be handled by experienced and certified dog trainers, although your role in the whole process is irreplaceable.

Canine Aggression Types
Click any of the links below to jump to each type of aggression.

Aggression Towards Other Dogs

Manifestations of dog on dog aggression depend on or are caused by a number of elements. It seems logical to start from the cause of it.

Aggression towards other dogs is most commonly the consequence of the lack of socialization and social skills, fear that does not necessarily have something to do with other dogs and dominant dog issues. Other than these three reasons, dog owner’s reactions may be what triggers the aggression.

According to this study, breeds with the greatest percentage of dogs exhibiting serious aggression (bites or bite attempts) toward humans included Dachshunds, Chihuahuas and Jack Russell Terriers (toward strangers and owners); Australian Cattle Dogs (toward strangers); and American Cocker Spaniels and Beagles (toward owners).


Socialization – Lack Of Social Skills

Socialization is a process that begins while puppies are still with their mother. It is based on learning to communicate with each other, learning the consequences of their actions as well as learning to control their body (for example, learning how hard they can bite before mommy induces the punishment or the other puppy begins to squeal in pain).

This step represents the basis of the process of socialization, and if stopped there, chances are that in older age your dog will have trouble communicating with other dogs, misinterpreting their body language as threatening and react by displaying signs of aggression.

It is obviously much easier to induce the socialization training to a young dog rather than to retrain an older one that has already adopted the patterns of antisocial behavior and aggression.

The strategy to approach the solution to this problem is not based on punishing the misbehavior, but rather encouraging good practice. In order to avoid incidents, by keeping a close eye on your dog, expose him to the company of the opposite sex dog that you know for sure does not have aggression issues.

The point of this is to step-by step socialize your dog under conditions that will not provoke him to react. It may take some time for your dog to adjust to other dog’s presence and reactions. In the beginning stages of the process, choose dogs that are unlikely to respond aggressively if provoked in order for your dog to adopt their patterns of behavior.

As you begin to notice the progress, under close supervision expose your dog to same sex dogs, again those with no aggression issues. Getting used to the company of other dogs and learning to read and not misinterpret their body language and actions is what socialization is all about. A dog that feels comfortable and confident around other dogs doesn’t respond aggressively to other dogs’ presence, no matter how notorious breed might be.

Fear Aggression In Dogs

Some dogs aren’t used to a crowd and react to noisy, unexpected situations or open space by displaying aggression. Bad experience with other dogs, such as some previous unprovoked fight that caused pain or injury, can also be a source of fear that is causing your dog’s aggressive response to other dogs’ presence.

There are cases of bad experience that turn out to be such a distinctive image in the dog’s memory that they result in producing particular kind of fear of a particular kind of dog.

For example, if your dog was attacked and injured by a husky once, especially if the incident was unprovoked by your dog, the image of all husky-like dogs is what is associated with pain and fear that may further on cause aggression towards all husky-like dogs.

Dominance Aggression Towards Other Dogs

A dominant dog is the one with a strong instinct to rule, that tends to be the leader of the pack and pushes all other dogs to submission. Pet dogs, even if you may not notice that, tend to regard the social group they are a part of as a pack.

Whether we are talking about the group of dogs he spends time with, or the human family he lives with, similarly to a pack, every member of the community has their place and a social role of their own. Most commonly, the person who the dog depends on the most is regarded to be the dominant figure, the leader of the pack.

The instinct to dominate is what some dogs are born with. Dominant dogs, if trained properly may not display this urge when it comes to the human community he is in, but rather in situations when surrounded with other dogs. This issue can be overcome with training, as well as socializing.

Exposing your dog to the other dogs’ company under super-close supervision and with a particularly careful choice of dogs to expose him to is the course of action regarding the socialization part. Start with the opposite sex dogs, with no aggression issues; domination issues most of the time turn into aggressive episodes when around the same-sex dogs.


The need to position himself or herself as the Alpha figure surfaces frequently in the interaction with same-sex dogs. This behavior pattern is equally common among males and females, and does not have much to do with breed or specific age. That is why it is so important to start the socialization process with the opposite sex dogs, and only when you notice progress proceed to the next level, which is socialization with the same sex dogs.

Choosing the training companion wisely is crucial, in order to avoid the clash of two dominant characters; the companion should be picked for its calm attitude and good social skills.

The parallel training task is based on rewarding for good behavior and punishing for the bad one. Keep in mind that this process takes time, patience and effort, but, as always, being consistent with the rules you aim to establish is very important. Remaining calm and not panicking is also an important factor.

After displaying a sign of aggression, announce that the game is over by taking your dog by the leash and making him sit or lie still, but don’t go home immediately. The signal you are sending is basically – you misbehave – you lie here bored and watch other dogs have fun. The goal is to establish the link between the action and the consequence.

Behavior misinterpreted as aggressive:

  • Barking on other dogs while on the leash – most commonly just a way to attract attention
  • Arguments that pop out over a toy or food
  • Response to bullying – if feeling endangered by the other dog’s behavior it is only natural for your dog to stand up for himself
  • Rough playing

Aggression Towards Your Other Dogs

Episodes or patterns of aggressive behavior between two or more dogs that live under the same roof are issues that need your interference in order to establish or reestablish healthy balance of power between your dogs and ensure peace in the house.

Aggression towards flat-mate dogs may origin from various sources such as dominant dog issues, jealousy, and to be frank, your mishandling of the situation.

Dominant dog

As we have explained before, the need to dominate is an element of character of some dogs. Having more than one dog, especially if the other one came to you significantly later than the first one may trigger a before unnoticed tendency to dominate.

Age and size needn’t necessarily be the conditions that determine one dog’s domination over the other. Or, you may just be unlucky enough to pick two dominant dogs, in which case you should dedicate yourself to properly training them in order to maintain the peace in the house.

Aggressive behavior caused by the instinctive need to dominate is easy to notice. One dog bullies the other one for no other reason but to prove his ‘reign’. Establishing a certain balance of power is a completely natural process, yet constant aggressive episodes point out that one of your dogs tends to dominate the other at any cost.

Aggression towards your other dogs

Depending on the character of the other dog, this may end up with one of both dogs being seriously injured or by having one dog with anxiety or fear issues caused by constant bullying. The solution to this situation depends on your reaction. Induce a punishment over the bully, for example by making him spend the afternoon in his basket, yet do not cause jealousy and even rougher bullying by being overly affectionate to the other dog.

In regular occasions, approach and treat both dogs the same, in order to clearly display the same amount of affection and love. If these guidelines do not show significant progress in solving the problem, you may have to consult a professional trainer.

How To Deal With Jealousy Dogs?

Some dogs have hard times accepting the idea of another dog living under the same roof. Aggression caused by jealousy is most common in situations where one of the dogs is living with you significantly longer then the other one. Even if you threat them both the same, one dog may feel intimidated by the idea of not being the center of your attention.

Aggressive episodes are basically a fight for your attention. Most common mistake owners make is paying more and more attention to the new dog thinking that way they will comfort him and help the adjustment process. The right approach is just the opposite – punish the aggressive behavior but maintain the same amount of attention and affection to both dogs.

Try keeping in sight both of the dogs in situations that you see as potential ground for an aggressive episode, and try preventing them by creating a distraction.

Owner – caused aggression

In some cases, the dog himself generates the jealousy, but in some other cases, your attitude is what creates the ground for jealousy and aggressive behavior. Some dogs accept the new one very well, positioning themselves as the mentors, making the training process way easier for you since new dogs tend to fit into new environment most of the times by mimicking the behavioral patterns of the older dog.

But, if the older dog, apart from his good will to accept the new one becomes the “old attraction” and starts to feel left out of your activities or starts feeling deprived of your attention, he may just act out by intentionally hurting or intimidating the younger dog. It’s on you to return balance into this relationship, by treating both dogs the same and especially by not depriving your older dog of the two-of-you activities that he is used to.

Training process of the younger one may come as a challenge of a kind also. The treats that you use to motivate and reward the younger dog may not only be the cause of aggressive episodes, but they even may inspire the older dog to behave in a manner of the untrained, younger one in order to earn the treats himself. To avoid this, reward the old dog with the treats also, whenever you do it with the younger one.

Common mistakes regarding the subject of dog aggression towards your other dogs:

  • Letting them “solve their issues themselves” – this may turn one of your dogs into being frustrated and a deeply unhappy animal pushed violently into submission
  • Treating dogs unevenly – punish the aggressive behavior of one dog, but don’t become overprotective of the other one in order not to create counter effect and heat up the animosity
  • Treat all your dogs the same – an even-balanced relationship between dogs may be spoiled by your mishandling of the situations. Make it clear that you love them evenly by paying equal attention to both of them (or all of them)
    • Aggression Towards Strangers

      When it comes to the subject of dog aggression towards human beings, the concern most owners feel is reasonable. Biting a stranger can cause a line of very unpleasant consequences, therefore, this issue is to be analyzed and approached with extra caution.


      Reasons that cause this type of behavior vary, and your approach to this issue should be based accordingly. Some dogs bite when they feel endangered by the presence of the strangers, and the cause to this may be a lack of confidence and a lack of proper socialization training.

      Some dogs are overly protective of their owners and of what they consider to be their home. There is also a chance that physical, health issues that your dog isn’t displaying in any other way may be what actually causes the aggression.

      Confidence and Socialization Based Aggression Towards Strangers

      The importance of socialization on multiple levels is crucial to the quality of life you share with your dog. On one level, socialization with other dogs, which even if neglected may, if handled wisely, be overcome by avoiding potentially dangerous situations.

      On the other hand, it is highly unlikely that you will be able to avoid an encounter of your aggressive dog with other humans but yourself. This issue may turn the everyday walk into a stressful, unpleasant experience. Some people who own dogs with this kind of behavioral problem refer to the simple walk under these conditions as a “living hell”.

      That clearly illustrates how big of a problem this may become. Rather than training, a huge number of dog owners reach for the quick solution and use a head halter or a muzzle. Although undoubtedly effective, halter will not solve the problem and you need to consider the fact that your dog will not always have it on. So, training combined with halter, if necessary, looks like aiming in the right direction.

      Adjusting your dog to the presence of strangers should begin at home, with the assistance of people that you previously prepare and direct. It all starts with keeping your dog on a leash, and letting him be present while the stranger and you are sitting around.

      Keep him on a short leash, and at any sign of aggression, growling, or teeth showing, pull the leash and command your dog to stay still. The stranger’s moving around the house while he is on a leash will most certainly provoke the untrusting dog to react aggressively.

      Be super-calm and remain still, as previously explained. If you feel comfortable with the progress, let the dog approach your guest (who is still sitting at this point) while still on the leash. If you do not feel completely comfortable with this strategy of training, keep a head halter or a muzzle on all along. This type of practice requires time and patience and many volunteers as well.

      After the dog adjusted to the presence of strangers in the space of his own, try the same practice while walking your dog on a very short leash and with a muzzle or a halter on, with one of your volunteer friends walking by your side and later by practicing to remain calm as the volunteer approaches you.

      Before starting the training regarding dog’s aggression towards people, consult a certified dog trainer. Some dogs are simply too strong, too stubborn or they simply don’t consider you to be the dominant figure, for you to handle the training on your own.

      Health Issues Based Aggression

      Some dogs instinctively tend not to display any signs of physical illness or pain they are suffering, in order not to become “an easy prey”. They sometimes release the pain-caused anxiety by aggressive episodes towards strangers.

      Check in with your vet and make sure that there is no medical condition causing this type of behavior. If there is, solving it will at the same time solve the aggression issues.

      Aggression Towards a Particular Person

      Aggression directed towards a particular person is an issue of its own kind. When the dog who is otherwise peaceful and calm, reacts by displaying aggression towards a specific individual, before proclaiming your dog to be aggressive in general, make sure that the two of them don’t have a history together.

      Some dogs react frantically to even a sight of the person who did them harm, and the time between the aggression display and the event that caused it could be measured in years.

      If you don’t receive any confirmation of the past interaction, and don’t see any logical explanation why your unaggressive dog reacts violently to a specific person, the easiest way out of that situation is to keep them away from each other if possible, or consult with a certified dog trainer.

      Aggression Towards Children

      This issue is obviously the most delicate one we have mentioned so far and therefore must not be overlooked!

      This problem won’t only mean putting a child into immediate danger of being physically injured but much worse – it may cause life long phobia of dogs and that itself is a hard issue to handle. Kids are more likely to be harmed by their own family dog, even if the incident is not a typical display of aggression.


      Family dogs consider small children to be pretty much like puppies, and based on that – they treat them like puppies. This sometimes ends up with kids being hurt without dog’s intention to do so, since the aim of dog’s action is basically to help the socialization of the “puppies”. Therefore, dogs’ interaction with small children should be under close supervision.

      Yet, the type of dog aggression obviously aimed towards children in general is to be handled with the greatest attention and with close collaboration with a certified dog trainer!

      Read our in-depth guide on introducing baby to a dog.

      Dog Aggression Towards Owner

      This type of behavior may originate from several sources, most common of which are related to the lack of training combined with dominant dog issues and previous bad experiences with humans in general.

      The dominant dog is the strong tempered one that tends to assert himself as the leader of the pack. This type of behavior is an inheritance of domestic dogs’ wild ancestors, which in today’s conditions isn’t seen as an acceptable pattern of behavior, mostly because of the element of the aggression and because of the fact that what a dominant dog considers to be a pack today means family of humans.

      A dog with serious domination issues doesn’t hesitate to use violence in the process of gaining or maintaining his position as the leader. Violence, in this case means aggressive behavior towards the ones he wants to put into submission. Translated to today’s conditions dogs live in, it means that the dominant dog will display episodes of aggressive behavior towards his owner who he seems as the strongest opponent in game of becoming the leader.

      If properly trained from the very beginning, these issues may never become noticeable or may be displayed as stubbornness of a sort. Yet, if untrained properly, dominant dogs may develop a habit of proving their position by physically attacking their owners on a regular basis.

      This situation is not to be easily overseen, especially as it becomes more intense as time goes by. Small dogs with this type of issues may cause problems, but big and strong dogs may end up terrorizing their owners and end up causing serious injuries.

      Trauma-triggered Aggression

      The second most common cause is a bad experience that triggers aggression on particular occasions. That bad experience may come from the owner himself or from someone else, yet the trauma that the dog suffers manifests itself through aggressive outbursts towards the owner.

      In both these situations it is highly recommendable to at least ask for a certified trainer’s advice if not begin retraining under his close supervision.

      Aggression and Objects

      A common cause of aggressive outbursts is dogs’ attachment to a certain object in his surroundings such as toys or something else he holds dear. This includes also dog’s attitude towards the food. This type of aggression is what can be prevented by a simple training strategy while the dog is still young.

      It’s not true that “no dog would ever give up his bone”, on the contrary – dog not afraid of being robbed of his “possessions” will have no particular problem with lending you even his bone. The truth is, though, that some dogs are more possessive over objects than others, yet this doesn’t mean that those dogs can’t be trained to be polite when it comes to objects of their affection.

      The training strategy regarding a strong sense of possessiveness is based on the concept of exchange. Train your puppy by taking his favorite toy from him, but by trading it for something better, favorite treats, for example. After the exchange takes place, return the toy that you have taken away, and that way reassure your dog that the fact that you are taking something of his doesn’t mean that it’s lost forever.


      This type of training progresses slower if started when the possessive attitude is already established firmly. If incidents that include aggression become frequent, you should most definitely consult with a certified dog trainer.

      Another type of object-related aggression is based on fear of certain objects. For example, a dog adopted from the streets that has been beaten with an umbrella, recognizes the umbrella as a threat. Aggressive outbursts of this kind are sometimes focused on the object itself, but sometimes it’s the person who holds the object that actually triggers the aggression and ends up being hurt.

      This type of aggression originates from the trauma, and however violent those outbursts may be, the delicacy of the issue that causes them mustn’t be overlooked. We suggest you to at least consider consulting a certified dog trainer regarding this matter, and approach solving this issue under his instructions and supervision.

      Dog Aggression Towards Other Animals

      Dog aggression towards other animas originates from the remains of instinctive behavioral patterns of wild dogs. Although our dogs have no reason to hunt for their food, the instinct to chase after other, especially smaller animals, remains.

      Not all dogs have the same interest in chasing and hunting other animals. The breeds that were originally created to hunt, chase and follow a blood trail to retrieve or to point at the hunted animal or that were designed to exterminate the rodents display a particular interest and aggression towards some particular animal species.

      Since most of the people keep their dogs as pets, completely undermining what they were genetically designed to do, it may come as a surprise when otherwise perfectly trained dog start to bring dead birds from the backyard or start to dig frantically in order to catch a mole.

      These examples are obvious illustrations of instinct-based aggression towards other animals. The genetic predisposition to fulfill a particular task is what motivates these aggressive outbursts towards certain species. To stop the dog from doing what he was designed to do means to create an inhibition that is likely to cause frustration.


      If built up, that frustration may produce a counter effect in forms of anxiety or aggression pointed into some other direction. Therefore, if forbidden to hunt, dogs with a strong instinct to do so, need to channel the energy into something else. That means that you need to create extensive plan of exercise in order to compensate for the inhibition.

      Some dogs show aggression towards the animals they feel threatened by, or by the animals that they haven’t encountered with before. Scent of the unknown animal species may be intimidating and may trigger an aggressive episode. In order to avoid either your dog or the other animal ending up hurt, keep these encounters under close supervision.

      The training strategy regarding control of the aggression towards other (domestic) animals is based on slowly adjusting the dog to the scents, appearance and the sounds that an unfamiliar animal produces, by exposing them to one another under close supervision, while inducing punishment if necessary.

      Consulting with a certified dog trainer is what you should consider regarding the issues of aggression towards other animal species in general. If you intend to get another pet, for example a cat, a bird of a sort or a small mammal, you should most definitely ask for the advice in order to avoid potential unpleasant surprises and risk of having an animal getting hurt.

      What to keep in mind when it comes to the subject of dog aggression:

      • Aggression is perfectly normal element of behavior that every dog is born with. Dealing with the aggression is an issue of dog learning how to control it
      • Aggression is a display of your dog’s emotions. Emotionally stable dogs reach out for it only if feeling seriously threatened
      • Figuring out what makes the dog feel threatened, means figuring out the source of particular aggressive episodes
      • Dogs usually display aggression when they feel physically threatened, when they feel someone or something they hold dear to be threatened or when feeling seriously frustrated
      • Some displays of aggression are instinct-related
      • Some displays of aggression are related to dominant dog issues
      • Some displays of aggression are triggered by the fear of the unknown, and to deal with them means to go through the process of adjustment
      • Most common displaying signs of aggression are growling, teeth-showing and biting
      • Aggression is not sex or breed related issue, although certain dogs do have predispositions to display an aggressive behavior
      • Younger dogs are easier to train in order to prevent aggressive episodes ever occurring
      • Aggressive dogs who have already developed patterns of an aggressive behavior are harder to retrain. In cases like that, do not hesitate to ask for the help of a professional dog trainer
      • Some displays of aggression are health related and to deal with them means to consult the vet
      • Be extra careful concerning the issues of dog aggression towards children and dog aggression towards yourself. Both issues need to be handled with special care, especially in cases of big and strong dogs. We advise you not to hesitate and ask for professional help of a certified dog trainer regarding all aggression issues, but these two cases we pointed out seem to us as potentially the most dangerous ones
      • Unless certain in your own training skills, ask for advice of a certified trainer. Aggression issues are not to be taken lightly, especially regarding possible risks