Is Your Dog Aggressive? What Can You Do? Get an Ethologist?

Translated by Nick R

Some dogs can threaten people or other animals by growling or barking, which can be very dangerous as these warnings can easily turn into aggression (biting).

Owners of this type of dog sometimes don’t realize from the beginning how threatening it can be and the situation gets worse, so, if this is your case, you must act quickly to avoid accidents.

Why is my dog aggressive? 

There are many reasons for a dog to be aggressive, in fact, all dogs at some point may threaten when something they don’t like happens or they feel insecure.

First of all, you must identify if your dog is always aggressive with everyone (people and animals) or only in certain situations that cause conflict.

I’ll talk about the types of aggression that dogs can show so you can analyze which one fits your furry one.

Types of aggressiveness in dogs 

Aggressiveness caused by fear and insecurity 

In this case, the dog reacts by attacking a stimulus that causes him fear. For example, dogs that have been previously mistreated by their owners or have had a hard life on the streets may react badly if they feel that someone or something is a threat to them.

So, if you fostered your dog as an adult, maybe you found him on the street and showed signs of mistreatment, this could be the reason for the aggression.

Aggressiveness due to illegal dog fights 

Unfortunately, illegal dog fights still take place in many parts of the world, and dogs are trained to literally kill their opponent. They have to be very aggressive to survive.

The “owners” of these dogs train them hard to be fierce and make them earn money by fighting other dogs, clearly, this is animal abuse and is heavily penalized in most countries.

For example, in 2021 the public prosecutor’s office in Madrid, Spain, requested 102 years in prison for members of a network of illegal dogfighters (La Vanguardia).

So, if your furry one was rescued from one of these illegal fights, this will be the reason for his aggressive behavior; he was specially trained for it and has survived these violent acts.

Aggressiveness for marking territory or protecting resources. 

Some dogs may see as a threat to other dogs, animals, or people if they approach their territory and precious objects, as they think they can be taken from them.

That is, if another puppy approaches their food, bed, or toys, your dog may act aggressively to defend his place. This type of aggression can also include females bearing puppies, who will try to defend them if they see someone as a threat to their puppies.

Aggressiveness due to lack of sociability 

From the 4th week of birth, the puppy enters its “socialization stage”, meaning that it is the moment in which the puppy is getting to know the world and everything in it.

This period is very important since it will determine the dog’s future behaviors. Your dog, in this stage, must be exposed to different stimuli and you must try to give him very positive experiences when dealing with other animals or people.

If he has a negative experience at this stage, perhaps another dog has bitten him or a person has hit him, it is likely that as an adult he will be afraid of these situations and may react aggressively.

Aggression due to frustration or stress 

An example of this type of aggression is when your dog is in a moment of stress, or a situation that generates a lot of frustration and you try to restrain him. When you tie him up or take him in your arms to prevent him from running away, he will try to bite whatever is restraining him or attack whatever is causing him frustration.

Aggressiveness caused by pain 

If your pet is in physical pain, either because of an illness or because he has suffered an injury, he may act aggressively towards you or whoever tries to help him: he won’t understand what is happening to him.

Or if you try to touch him and cause him pain, he will clearly try to defend himself.

Aggression from a female in heat 

The scent emitted by a bitch in heat can encourage the males around to compete or fight with the others for her. This is more common in dogs that have not been spayed or neutered.

Proper training for a dog 

Many times aggression in dogs is caused by a lack of training in obeying the owner and learning to manage different types of impulses in different situations.

If you have a puppy, you should train him as soon as possible, it is not really difficult because you can teach him basic tricks such as sitting, staying still, lying down or coming when you call him.

This will give you security in moments when your dog faces a bad situation. If he is trained, he will listen to you and control the fear, insecurity, or frustration.

Otherwise, if your canine is an adult, you can also train him without any problem; however, if he is already aggressive, you should analyze the situation very well: can your dog be a danger to you when training him?

If so, it is better to contact an ethologist or a professional trainer to help you change your dog’s negative behavior.

What do you need to train your dog yourself at home? 

If you decide that your pet is not so dangerous for you after studying it carefully, check the following indispensable elements to start training it.

A quiet place 

First of all, find a place free of distractions for the dog, and a place that provides him with security and not stress.

Positive reinforcement 

Always use positive reinforcements such as snacks or toys that your dog loves, this will make him happy and attentive to what you are trying to explain to him.

Short sessions 

If the puppy has not previously been subjected to training, it is best to do short sessions of 5 to 10 minutes a day so he doesn’t get bored or stressed.


This will always be required when training any canine as training should be a time of fun and not stress. Also, especially when dealing with an aggressive dog what we want is to convey security and calmness and not encourage him to be aggressive out of stress or frustration.

If you want to learn more about dog training at home, and the proper way to teach him many tricks you can read the article How to train your dog + 15 tricks your dog will love to learn at home.

When to resort to the guidance of an ethologist 

When dealing with a very aggressive dog, which has probably already attacked other animals or people, it’s advisable to seek professional intervention to avoid potentially dangerous situations.

Ethologists are professionals dedicated precisely to understanding animal behavior. They will study the dog in question, deduce where the aggressive behavior comes from, and based on their analysis, they will give you solutions to put an end to it.

Steps to know if I need an ethologist 

  1. The first thing you should do is go to a veterinarian to rule out that the aggressiveness problem your dog is showing is due to an illness or some kind of injury that is causing changes in his behavior.
  2. If it is not a medical condition, the veterinarian will probably recommend you to contact an ethologist, so ask him to recommend a reliable one.
  3. Usually, after talking to the professional, he/she will conduct an interview to begin to understand the situation; since when your dog has had this behavior, in what situations, and towards which animals or people.
  4. The next thing is that he will observe your dog to determine the causes of the behavior and then he will indicate to you what steps should be followed, together with the owner, to eradicate the aggressiveness.

This way the real cause of your dog being aggressive will be ¨attacked¨, to put an end to this behavior and make sure it doesn’t happen again. Previously I explained the types of aggression, if you do not act properly on the one your dog has, it can worsen the situation.


So, if you have a canine with aggressive tendencies at home, the best thing you can do is to observe him understand where it comes from or what that aggressiveness is directed to, and if necessary contact a professional to change that behavior.