How to Solve Aggression in Dogs

causes of aggression in dogs
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It can be a frightening experience to be around an aggressive dog. It's even scarier when it's a dog that is usually docile and friendly but then suddenly becomes aggressive, growling, lunging, or baring its teeth. In an extreme case, the dog may bite or attack you or a family member it knows well and has never acted against before.

What should you do when your dog shows these signs of hostile behavior? Since dog aggression can get out of hand and lead to injuries to dogs or people, it's very important to find the cause so you can help your dog overcome the aggression.

Why Do Dogs Show Aggression?

Knowing why your dog is acting aggressively is essential to figuring out the best plan for stopping this frightening behavior. There are several potential causes of aggression in dogs.

illustration of causes of aggression in dogs
Illustration: Katie Kerpel. © The Spruce, 2018

Illness and Injury

Some medical conditions can cause dogs to become aggressive. If a dog that has never shown any sign of aggression suddenly begins growling, snapping, or biting, it may be caused by a disease or illness.

Pain is an especially common cause of aggression in dogs. Your suddenly aggressive dog may have an injury or an illness that's causing major discomfort and stress. Some possible causes of pain include arthritis, bone fractures, internal injuries, various tumors, and lacerations.

Other illnesses may affect your dog's brain, leading to seemingly unreasonable aggression. Conditions such as cognitive dysfunction and brain diseases or tumors may provoke the onset of aggression. These problems are more likely to occur in older dogs but can happen at any age.

If your dog is exhibiting sudden, unexplained aggression, talk to your veterinarian before attempting to address it as a behavior problem.

You may be tempted to try giving your dog medication to relieve pain, but this is something you should not do. If your dog is sick, you'll need to know exactly what is wrong with it before you begin any treatment. Don't try to take matters into your own hands until you know what you're dealing with. only a veterinarian can advise what medications are appropriate for your dog.

Fear

A fearful dog can easily develop aggressive behavior. Most dogs only exhibit aggressive behavior if they sense that they are in danger, cannot escape, and feel the need to defend themselves. For example, this may occur if a dog is backed into a corner with no way out or if he thinks a hand raised over its head means he is going to get hit.

If your dog is a rescue dog that exhibits aggressive or fearful behavior more than is normal, it may have been abused, neglected, experienced a traumatic event, or not properly socialized as a puppy. Any information you can get from the organization where you adopted the dog could help you determine the best way to handle the situation.

Sometimes rescue dogs need obedience training with an instructor who specializes in teaching dogs that have been abused or those that have not been properly socialized. In some cases, you may be able to manage your dog's fear on your own with training and patience. You can speak to a veterinarian about the best course of action.

To avoid provoking this type of aggressive behavior, approach unknown dogs carefully (better yet, let them approach you). Train and socialize your dog to help prevent fear down the road.

Possessiveness

Possession aggression, or resource guarding, occurs when a dog is possessive of something. This is often food, toys, or some other object of value. A dog that exhibits possession aggression may growl if someone approaches his food bowl or gets too close when he is chewing a favorite toy.

A dog may also bite a stranger who steps into your home, which is the dog's territory.

The degree of aggression may vary from one dog to another and between objects. For instance, your dog might not care if you sit down and pet him while he chews a rubber toy, but he may turn and snap at you when you do the same thing while he chews a pig's ear. It all depends on the value that the dog attributes to each object or resource.

Dog pulling toy from man's hand
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Show of Dominance

Dogs sometimes behave aggressively as a display of dominance. This is often directed toward other dogs, but it can occur with people as well.

It's important to understand that dominance is a behavior, not a personality trait. Dogs are not dominant or submissive "by nature". Some may have tendencies towards one behavior or the other, but this is typically determined by the circumstances.

Dogs that display dominant behavior feel that they must prove they're in charge of a situation. The growling, snapping, or biting occurs when they feel their position is being challenged.

Unfortunately, people often mistake the cause of canine aggression as dominance-related behavior when there may be another cause. In reality, aggressively dominant behavior is not nearly as common as the other causes of aggression.

Two Dogs Fighting On Lawn
Cindy Biell / EyeEm / Getty Images

Frustration

Aggression that's caused by frustration is often referred to as redirected aggression or barrier frustration. It occurs when a dog is frustrated at not being able to get to something and takes its frustration out in another way. This type of aggression is common in dogs that spend a lot of time tied up, restrained on a leash, or behind a chain-link fence.

For example, a dog that's chained in a yard may spend the day straining to get to a dog that lives across the street or in an adjacent yard. The restrained dog usually barks and growls more fiercely as the frustration grows. When the owner approaches, the dog may redirect its frustration and bite the owner.

Be careful not to misinterpret your dog's aggression. Always rule out a health issue or fear before you assume you know the reason for your dog's aggressive behavior. Otherwise, attempts at corrective measures could actually make the problem worse.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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