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What Makes Dogs Aggressive – Common Reasons

Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Published on
Thursday 5 May 2022
Last updated on
Tuesday 9 May 2023
what makes dogs aggressive
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After seeing your dog snap or growl for the first time, you might be wondering what makes dogs aggressive. Aggression in dogs has many causes, but most come from a place of fear and anxiety. This is why managing your dog’s aggressive tendencies quickly and in a positive manner is important.

When looking at what causes dog aggression, it’s important to cover the signs of aggression as well as the different types. So, to find out more read on with us!

Signs of Aggressive Behavior

Most dogs will give plenty of appeasing signals before they escalate to biting. These signals can be placed on something called the “ladder of aggression.” At the bottom rungs of the ladder, we have yawning, blinking, and lip licking. Next is turning the head away, then turning the body away. After this comes walking away, followed by creeping with the ears back. Further up we have standing crouched with the tail tucked under. Lying down with a leg up brings us further to the top. Lastly comes offensive aggression, where we see stiffening, staring, growling, snapping, and then biting.

dog ladder of aggression
Ladder of Aggression in Dogs

Classification of Aggression

Aggression in dogs takes many different forms. These range from fear aggression, to territorial aggression, to redirected aggression. While some types have similar roots, usually based in fear or anxiety, the way that each type is managed differs. This is why it’s important to be educated on the types of dog aggression.

Fear Aggression 

Fear aggression may be one of the most common forms of aggression in dogs. In reality, many types of aggression have a basis in fear or anxiety. The early manifestations of fear aggression are shown in defensive aggression. This is displayed to placate or put distance between themselves and the threat. In this stage, your dog will give conflict-appeasing signals, also known as calming signals, to diffuse the conflict. Your dog might avoid eye contact by squinting, yawning, licking their lips, flattening their ears, stiffening, freezing, crouching, growling, or snapping. When your dog starts to close this distance between themselves and the perceived threat, offensive aggression starts to show. The purpose of this type of aggression is to make the frightening stimulus go away. Dogs who display fear aggression are not “mean” or “bad” dogs, rather, they are afraid about a perceived threat or anxious about an unpleasant outcome.

There are several things that you can do to manage fear aggression in a dog. First and foremost, keep your cool yourself. Do not punish your dog when they are fearful. By punishing your dog you only make them more fearful and reinforce their aggressive tendencies. Second, study dog body language thoroughly. Your dog will give you many appeasing signals before they escalate to offensive aggression, and you must learn to spot these if you are to work with your dog. Also, set your dog up for success. Prevent situations that your dog finds threatening. For example, if your dog does not cope well with new people, confine them to another room with treats or a toy when you have visitors in your home. Create positive associations by pairing a stressful situation with toys, treats, or play.

Territorial Aggression

Instinctively, dogs will guard resources that are important to them. These resources might include food, beds, toys, and even people. Territorial aggression branches off from this tendency, but on a greater scale, and often involves the boundaries of the dog’s home. Dogs who are territorial may run along fence lines, bark, and charge at people who invade the dog’s territory. While some may label these dogs as “dominant”, these dogs are often insecure and need to control who and what has access to their living space to feel safe.

If your dog aggressively protects their territory, it’s important to get the help of a qualified positive trainer. A qualified trainer can help to desensitize your dog to their triggers, whether they be someone approaching your dog’s territory or seeing another dog nearby. The goal of training would be to get your dog to accept the approach of people or dogs into their territory and to relax in their presence.

types of dog aggression
Most dogs will give plenty of appeasing signals before they escalate to biting.

Resource Guarding

Resource guarding happens when your dog controls access to people, objects, and most commonly, food that is important to them. In dogs, resource guarding typically comes from anxiety and insecurity, as well as an inability to cope well in social situations. A dog who displays resource guarding aggression might see anyone as a potential threat to an important resource, and will not tolerate competition. The idea of losing the resource will make a dog more vigilant and irritable.

Many people misunderstand why their dogs guard their resources and get angry and confrontational with them. This, however, only serves to increase the perceived competition, causing the dog to guard their resources more. Using punishment on a resource guarding dog does not address the underlying issue and only aggravates more defensive behaviors. When left unchecked, resource guarding behavior can become dangerous. This is especially true if you have small animals or children in your home, who may not pay mind to your dog’s boundaries. So, it’s better to seek professional help sooner than later to address resource guarding issues.

Predatory Aggression

Predatory behavior in dogs is not typically emotionally driven, instead largely influenced by genetic factors. While sighthounds are excellent chasers, Labradors are adept at flushing and retrieving, and these talents shine through in their predatory sequence. The full predatory sequence goes as follows: eye, orient, stalk, chase, grab, kill, dissect, and consume. So, while other types of aggression increase the distance between the dog and the threat, predatory instincts serve to decrease this distance. Some dogs express their predatory behavior by chasing other animals or moving objects, but this only fulfills the beginning of the instinctive predatory sequence. Many dogs enjoy shaking and pulling toys apart, and many herding breeds are great at eyeing and stalking their “prey” without attacking the animals that they herd. Dogs who are motivated by the final parts of the sequence can be difficult to live with, especially where small pets and children are involved.

It’s vital to know your breed well, especially if they are a working breed. You must find outlets for your dog’s working drive, whether it be through dog sports like flyball or agility, or through vigorous exercise every day that meets their needs. It’s also essential to teach your dog reliable recall. Some working breeds like sighthounds cannot be walked off-leash in an unenclosed space, as their drive to chase moving things is far too strong.

Dog-to-Dog Aggression

Dog-to-dog aggression can be extremely stressful for both dogs and owners. Typically, dog-to-dog aggression occurs when a dog is uncomfortable around, or poorly socialized with, other dogs. This might be due to a traumatic experience that causes them to fear other dogs. Play between dogs should go both ways, and dogs should take turns to chase each other with neither dog being made a target unfairly. Unfortunately, some owners do not notice the signs of aggression building until it is too late, perceiving the behavior as normal play. A playing dog should not become stiff, freeze, give a direct stare, or lift their lip. While it is normal for dogs to growl during play, the growling comes alongside loose and relaxed body language – where growling occurs alongside the aforementioned behaviors, it’s a sure sign of escalating aggression.

It’s important that you don’t punish, bully, or intimidate a dog who shows dog aggression. Your dog must learn that good things will happen to them when they see another dog, and to reinforce the good behavior when they don’t aggress. This builds up positive feelings towards approaching dogs. By jerking, restraining, or scolding your dog as they walk by another dog on a leash, your dog not only learns to fear you but to associate the other dog’s presence as a trigger for punishment. This feeds into your dog’s insecurity and makes their aggressive tendencies worse. It’s best to build up the positive training techniques with the help of a qualified positive trainer who can guide your dog’s social interactions.

Dog-to-Human Aggression

Dog-to-human aggression is very serious and poses a threat to other dog owners as well as the general public. But dog bites seldom occur “out of nowhere” and many dogs would prefer to avoid conflict than to bite, but some will resort to biting when warnings have been missed or ignored. Once a dog has bitten once, they have shown their willingness to use biting in at least one situation, and are more likely to do it again. However, it’s important to consider what led up to the aggressive behavior – anxiety, conflict about what to expect, and fear of punishment are just some of the factors that will lead up to a dog bite. Each context is separate, and just because a dog defers once in a situation, it does not mean that they will do it again.

Your safety is the essential first thing to secure when dealing with a dog who is aggressive towards people. Identify all situations that might lead to your dog becoming aggressive and prevent these. You might do this by muzzling your dog or using a leash and head halter control, depending on the situation. You will need the help of a qualified positive trainer if your dog shows aggression towards people often. A trainer can help to identify what triggers your dog, teach them new responses, and desensitize where possible. And, as a pet parent, you must provide consistency, patience, and predictability for your dog through reward-based training and consistent responses.

Redirected Aggression

Redirected aggression occurs when excitement, frustration, or arousal that is directed towards a target is redirected to whatever is closest. This often happens when the dog is unable to reach the intended target or gets interrupted. A common example of this happening is when owners attempt to break up play or fight between two dogs. The fighting dogs may turn and bite the person attempting to separate them. Another example is when an owner walks a dog on a leash and they get overly-stimulated, turning to nip the handler. This form of aggression always occurs when the dog is in a state of arousal. Usually, dogs who are susceptible to redirected aggression have underlying issues with anxiety. These dogs may react quickly and have difficulty calming themselves when aroused. So, it’s important to find what frustrates your dog the most and stop it before it starts wherever possible.

Because redirected aggression stems from arousal, it’s important to teach your dog to stay calm around their triggers. For example, if walking on a leash is a trigger for your dog, get them to focus on you. If you can keep their focus off of the leash restraining them, you may be able to keep them from going into a hyper-aroused state of mind. It’s sometimes better to remove access to the trigger altogether if possible. For example, if your dog fights with others through fences, keep them away from the places where these fights start. The less your dog has access to their triggers, the less likely they are to become hyper-aroused, and redirected aggression becomes less likely to happen.

dog to human aggression
A trainer can help to identify what triggers your dog and teach them new responses.

What Makes Dogs Aggressive: FAQ

Are you still wondering what makes dogs aggressive? Feel free to check out our Frequently Asked Questions for more details. If in doubt about your dog’s behavior, talk to your vet or a qualified trainer.

Can aggression be diagnosed? 

A qualified trainer can “diagnose” the cause of your dog’s aggression. Alternatively, a vet can help to find if there are any underlying physical issues at play. If your dog is in pain, they might become more aggressive to protect themselves. If your dog is showing unusual aggression, consider working with a vet and a qualified dog trainer to resolve the cause.

Why is my dog aggressive towards cats?

Some dogs with a high prey drive will chase cats. This is particularly a problem for dogs like ex-racing Greyhounds who have been taught to chase a lure – however, it is possible to “de-train” some dogs to live with cats. The detraining process takes a lot of time and patience from both the owner and the dog in question. It’s important to introduce your dog and cat gradually. At first, keep your dog on a leash and muzzled indoors during the introduction period. Whenever your dog shows disinterest in the cat, reward the behavior. We wrote a full guide on how to introduce a new dog to an aggressive dog.

Are some breeds naturally more aggressive than others?

Certain dog breeds are more prone to dog-to-dog aggression than others. This is largely due to what the breed was bred for originally. For example, the Akita, which was bred to guard and protect, tends towards aggression toward same-sex dogs. Similarly, the Dogo Argentino, bred for hunting large game, tends towards dog aggression and may be aggressive towards other animals. If you own a breed that tends towards a specific type of aggression, consistent training early in life is essential.

Should I punish my dog if it is aggressive?

You should not punish your dog for showing signs of aggression. There are several reasons for this. Firstly, punishment does not teach your dog what behavior you want to see. It simply reinforces their anxiety and can actually make their aggressive tendencies worse. It may also create an association that, again, reinforces your dog’s aggression. For example, punishing your dog for reacting to other dogs teaches them that other dogs bring punishment. As such, you must work on positively reinforcing the behaviors you want to see. Create positive associations between the stressor and your dog.

What makes dogs aggressive?

The leading causes of aggression in dogs are fear, anxiety, and pain. Your dog’s insecurities may manifest as aggression if left unchecked. For example, a dog who is insecure and anxious might feel the need to guard their resources against you. A dog who has been through a traumatic experience might become aggressive around other dogs.

If your dog has issues with aggression, it’s best to talk to a vet and a trainer for professional advice.

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