What causes dog aggression?

What causes dog aggression?
What causes dog aggression?

Dog aggression is a common problem for any dog owner and most people would agree that this one of the most serious, if not the most serious dog related problem of all. The reason for this is simple. While it might be very annoying with a dog who is not properly potty trained or who is pulling the leash when walking, aggression is much worse because it is potentially dangerous. A big strong dog can seriously injure or even kill other pets or human beings and therefore aggression in dogs must be dealt with as soon as it occurs or the situation will only get worse and the problem will be more difficult to fix. In this post, I will talk about what causes dog aggression  and how to deal with it.

Aggression is natural for dogs just like it is for human beings. In the wild, dogs get aggressive to protect their cubs or other members of the tribe or their territory. When being aggressive you can scare away enemies and if needed you will fight to defend your territory or tribe. Aggression in combination with great motivation (such as when a mother defends her cubs) can sometimes make a weaker animal defeat a stronger one so aggression is important in order to survive.

So aggression is natural and needed for survival and thus something you can never completely erase from a dog’s mind, however this can be controlled so it does not cause any problems. When our domestic dogs get aggressive it is often because it perceives other dogs and human beings as threats and thus in order to manage your dog’s aggression you must teach it that the people and other pets in your surroundings does not pose any threat.

What causes dog aggression?

There are different causes of why a dog becomes aggressive, these are the most common ones:

  • Fear: Fear is the most common reason why a dog becomes aggressive. If a dog is afraid and there is nowhere to escape (For example when the dog is attached somewhere), the dog will show aggressive behavior and sometimes attack and bite.
  • Resource Guarding: Some dogs will become very obsessive over their possessions. Things like their bed, favorite toy or food can make a dog growl, snap or even attack if other dogs or sometimes even humans approach their belongings. Resource guarding can result in serious attacks if not dealt with so this something that should be taken care of as soon as possible. A common problem when it comes to resource guarding is aggression around the food bowl in which case it becomes aggressive towards its owner.
  • Territorial: This is when a dog becomes fiercly protective over his/her territory (like your house and garden). Some dogs will only bark when strangers pass, this is only to alert and not a major problem, however some dogs will growl, bark and lunging after anyone who is approaching its territory. Should a dog like this manage to escape from its garden, there is a big risk that it will hurt somebody.
  • Leash Aggression A dog who is generally calm but who start pulling, barking and lunging after other dogs (or sometimes human) as soon as the leash is put on is usually scared. Being attached and restrained does not give the dog an escape path and thus it is displaying aggression to keep other dogs/humans away.
  • Frustration. When a dog is not being able to get to something (for example because it is attached or enclosed) it can sometimes take out its frustration on something or someone else, so any human or animal that comes in its way maybe a victim for this aggression. This also often the case when a dog does not get enough physical and mental exercise. This makes the dog nervous and frustrated and this can easily turn to aggression.
  • Anxiety can sometimes turn to aggression. A dog might become anxious because you leave the house without it or because of a new pet or family member or a new neighbor.
  • Social Aggression. If there are several dogs living together then there is usually a hierarchy among them and the leader of them get the best spot to sleep, the funniest toys and the best food. Should a lower ranked dog take what a higher ranked dog considers to be his/hers the leading dog might snap or growl. This is a natural behavior among dogs and not a problem unless this turns in to a fight for the leadership of the pack. If it does then this has to be dealt with.
  • Illness If a kind and playful dogs who usually enjoys playing with other dogs suddenly becomes aggressive then there is reason to believe that this is medical issue. Some medical conditions can make a dog aggressive and especially if the dog is in pain. If this is the case then a visit to the veterinarian is advised.

How to stop dog aggression

If you have an aggressive dog then the first thing you have to do is to figure out the cause of the aggression. You can do this by asking yourself the following questions.

  1. When did your dog’s aggression problem start?
  2. Is it aggressive towards other dogs/pets, strangers or even you?
  3. In which situations is it aggressive? When walking? Meeting strangers? Other dogs? In the garden? At feeding time?
  4. Has your dog suddenly become aggressive and there is no apparent reason for it?
  5. Is your dog an adopted rescue dog? Traumas in your dog’s past life might make it scared and cause it to become aggressive in certain situations.

Let’s go through the questions one by one.

causes of aggression in dogs1. If a dog is very calm and friendly and then suddenly becomes aggressive then a medical problem is probably what causes the aggression. Some diseases have this effect on dogs and in some cases the pain that a certain disease might also cause the dog to become aggressive. If a puppy starts to become aggressive at feeding time then it is a question of leadership. In the wild, the leader/leading couple eats first and when they have finished the other eats. Thus, the leader, in this case you should control the food and decide when the puppy can eats. Thus, the puppy is challenging your leadership and tries to take control of the food. You must stop this and re-establish your leadership.

When there is a new family member such as a new born baby then this can also cause aggression. This is due to jealousy and the dog might feel like the “stranger” has taken its place and is getting all the attention and affection. What you should do in that case is to give your dog a fair bit of affection and attention when the baby is around. That way it will be far easier for the dog to accept the newcomer.

So, if your dog suddenly becomes aggressive, you must think of the circumstances around you and figure out if something in your surroundings has changed and thus are causing your dog to become aggressive.

2. Is your dog aggressive towards other dogs? In this case it could be fear, it might be afraid of the other dog. It might also perceive the other dog as a threat to you. It can also be that your dog sees the other dog as a rival. If your dog is aggressive towards other dogs, take a look at this post: How to stop dog aggression towards other dogs.

If on the other hand your dog is aggressive towards people then the people are usually seen as a threat to you and your family or the dog is simply scared of the stranger and reacts with aggression. Whatever the case here you need to show your dog that stranger poses no threat to you nor to your dog. Here is a post with a video on how to show your dog that a stranger poses no threat. How to stop dog aggression towards people.

In the case that your dog is aggressive towards you it is most probably a question of leadership. If your dog does not consider you as its natural leader then it might react aggressively in a number of situations where you and your dog have conflicting ideas on something. In this case it is absolutely vital that re-establish leadership over your dog. Doing this is not as difficult as you think and it is not a question of dominating your dog. Instead, it is about showing your dog that your are its leader through your behavior. If you act like a leader your dog will consider you one.

For example when leaving the house, you go first because in a dog’s world the leader always goes first. At dinner time, you and your family eats first and then the dog. When you walk your dog, he/she should walk next to you and not pull ahead. All these little things might not mean a lot to us humans but to a dog they are very important and they determine who the leader is. Since you supply all that your dog needs and wants it is not difficult to be in control and in charge of things. By following this you will soon establish yourself as the pack leader and your dog’s aggressive behavior will come to an end.

To Summarize

  • Aggression is natural to a dog and in the wild it is necessary for survival.
  • If your dog behaves aggressively towards other pets, people or even you, then this has to be dealt with as soon as possible as this problem only will get worse and is potentially dangerous
  • In order to solve the aggression problem of your dog, you first need to determine the cause of the aggression.
  • Once you have found the cause of aggression you can take action and cure the problem.
  • If your dog is aggressive towards you then it is most probably a question of leadership and in that case you need to re-establish yourself as your dog’s leader.

Where to get help with your dog’s aggression problem

Aggressive behavior must be dealt with as quickly as possible and if you feel that you can’t manage it should get professional help. In the case of a severe aggression problem with a big strong dog a personal dog trainer would be your best bet as aggressive behavior can be dangerous and personal assistance would make the training easier and safer.

It is important to check the dog trainers credentials as aggression is a serious problem and you need a person who really knows what he or she is doing.

If there is no professional dog trainer available where you live then you might want to consider an online dog trainer. An online dog trainer can of course not assist you personally but he/she can show you the techniques needed and answer your questions should you run into trouble. By watching videos of a professional dog trainer working with aggressive dogs you can learn how it is done and if you need help, the online dog trainer is available via Skype, e-mail or a forum. If you want to learn more about how an online dog trainer can help you, check out This Review of the Online Dog Trainer. or go directly to the Online Dog Trainer to learn how they can help you with your dog’s aggression problem.

Yes, Help Me with my dog’s aggression problem

I hope you enjoyed this post and that you found it useful. If you have any questions, tips or tricks you would like to share, please post them below.

All the best,



Comments 8

  • Hello Jojo!

    In my opinion, especially dogs that belong to traditionally aggressive species like Pitbull and Rottweiller need to be very much taken care of. There were tragic situations when dogs belonging to delicate species caused some human lives to be lost. Then surely, whatever species the dog belongs to (even the tiniest ones!), aggressivity means a problem.

    And there are also cases when owners enjoy themselves by having aggressive behaviors towards their dogs and provoking them, finding it funny and amusing – that’s a harmful behavior and it will turn against who caused it, but unfortunately other people visiting that house may be affected by the dog’s aggressivity too.

    Not only we have to be careful about how to behave to each other, the way that we treat animals matters as well. And dogs have priority among our animal relatives!

    Bets regards, Peter

    • You are right, dogs needs to be properly raised and trained and aggression is the most dangerous of all dog’s behavior. In fact all dogs can get aggressive but of course the bigger and stronger the dog is the greater the danger. Some breeds do have a tendency for more aggressive behavior than others but it is also an individual thing and some dogs are more aggressive than others though you really can change the behavior of an aggressive dog and make it calm and relaxed.

      Dogs are a reflection of their owners and yes, owners who provoke their dog’s will make them aggressive and their dogs will pose a danger both to the owner and to other people and other pets. Some people should not have pets, it is as simple as that.

      Kindest regards,


  • Dog aggression problem is not a thing that just started today. In fact, many people have been having this issue for ages. A long time ago when I had a pitbull, I felt it was something peculiar to the breed but I didnt understand the issue problem properly. It is nice of you to discuss this issue here. I am very sure that many people will be able to learn from this. Good job.

    • Thank you,

      you are absolutely right. A lot of people don’t understand why their dogs get aggressive, they think it just the dog’s personality or the particular breed and that there nothing to do about it, The thing is, you can always gain control over a dog’s aggressive behavior, even if you can not completely erase it. You just to learn the reason why your dog is aggressive and then find the right solution for it. With some dogs it might be a little more difficult than with others but there is almost always a solution to this problem.


  • Hi Jojo! I was looking for information on how to train dogs, since I would like to get a border collie. I have been watching Nat Geo Wild and saw some documentaries on this subject matter. Online, I ended up on your website. I always told myself that if one day I got a dog, I would need the help of a dog trainer. I have never had pets in my youth. So, thank you ! I will definitely consider the Online Dog Trainer.

    • That is just great. The Online Dog Trainer will teach you all you need to know about raising, training and caring for your dog.

      If I can be of any help, feel free to contact me any time and I will do all I can to help you.

      All the best,


  • Hi. I know this is a common problem among dog owners but I never imagined I would go through this problem. It has been since a few months ago that my pet started to show this agresive behavior. And it has been escalating. Your post has helped me to consider all the possible causes and I believe that the trieger is fear. Thank you very much for your post.

    • You are welcome. It is good that you act now before it gets worse. Aggression is always easier to handle in beginning than if it has been going on for a while. So try figure out why your dog gets aggressive and then find the right solution for it. I would gladly help you so just contact me if you feel I can be of any help.

      I wish you the best of luck.


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