One rainy day, when a loud boom of thunder startled Joan’s friendly dog, Louie, the dog bit her friend Pam hard enough to draw blood. Following county laws, Louie was placed in a quarantine. This dog’s fear-based aggression had consequences for Louie (quarantine), Pam (medical treatment), and Joan (liability).
One of the most common causes of dog aggression is fear. A dog with fear aggression may seem to react irrationally or randomly, but there is always a reason that, to the dog, signals danger and a need to flee. If that’s not possible, they will fight.
It’s up to you, as the dog parent, to figure out what is causing the problem, recognize the warning signs (e.g., growling before biting), and determine how to fix the dog’s aggression towards other dogs, other animals, or people. Dog training for fear aggression is not easy, but it can be done for most dogs.
What Causes Fear Aggression in Dogs?
Fear aggression is a situation-specific issue that happens when the dog feels uncomfortable. It’s like the dog is thinking, “If I react this way, it’ll get me out of this situation!” And sometimes it does.
The Instinctual Defense Drive
We group dogs’ instinctual behaviors into three categories:
- Prey Drive: hunting, killing, and eating prey
- Pack Drive: living in groups and reproducing
- Defense Drive: responding to danger through fight or flight
A dog’s fear aggression stems from the Defense Drive. Something has given the dog reason to fear it, and one response is to fight back in the act of self-defense.
What Triggers Fear?
Dog fear aggression can be triggered by anything that becomes associated with a threat. Your dog’s fear aggression may originate with someone in their past who mistreated them, and now they fear anyone who looks, sounds, or smells like that person. Maybe umbrellas remind them of something that hurt them, and now they attack umbrellas being opened. Many dogs are afraid of thunderstorms, fireworks, and other loud noises. And if a dog hasn’t learned to socialize well, crowds, unfamiliar settings, and people and dogs they don’t know can also create a fear response.
The Dog Parent’s Role
It’s not unusual for a dog parent to unintentionally encourage their dog’s aggressive behavior. For example, if your dog sees another dog across the street and starts pulling on the leash to get to that dog, do you try to comfort the dog? Do you pet them and tell them it’s okay in an effort to calm them? Unfortunately, your dog will interpret that as, “It’s okay to go get that dog!”
Also, if a pet parent has not established themselves as the pack leader, their dog might take on that leadership role. In playing a role that’s not meant for them, they are constantly fearful, and they may try to protect their people when protection isn’t needed.
Another mistake people often make, especially children, is ignoring or not understanding the dog’s warning signs, such as growling. That may lead to a bite.

Who Does the Training?
Should you train your dog to stop acting with fear aggression or seek help? It depends on how comfortable you are with the situation.
Your Capabilities
Give some thought to your ability to train your dog. Ask yourself:
- How much experience do you have as a dog parent?
- Have you trained dogs before?
- Does your dog see you as the pack leader?
- How intense is your dog’s aggression?
- Do you feel safe?
- Do you have the time?
If you intend to train your dog yourself, plenty of information is available in bookstores and online to help you. One resource that we recommend is our book, Dog Training for Dummies, by Jack and Wendy Volhard.
Professional Trainer
There’s nothing wrong with reaching out for help if you are not comfortable training your dog. If you’re anxious, the dog will know. Especially in severe cases, it is safer to bring in a dog behavior expert. A trainer knows how to quickly get to the heart of your dog’s fears, address them, and teach them to react to those stimuli in a more confident, socially acceptable way. Ask your veterinarian and other dog parents for recommendations.
How to Stop Dog Fear Aggression
You won’t cure dog fear aggression overnight, but with patience, proper guidance, and in some cases, professional help, it can be done.
The Benefits of Exercise and Play
Ensure your dog gets enough exercise to use up stored energy that may otherwise be applied to aggressive behaviors. Walks, running in the park, and playing go a long way toward reducing aggression. Try a game of tug of war, which redirects defense drive behavior to something enjoyable.
The Long Down
This training exercise addresses impulse control in a high fight drive dog and helps establish you as the one in charge. You place the dog in a Down position, and they must stay for 30 minutes. It’s okay if they fall asleep; they just need to stay put for that 30 minutes.
A Structured, Predictable Environment
An environment with too many unknowns often triggers a dog’s fears. A high-in-flight-drive dog will not be comfortable with strangers, other dogs, or new situations. Of course, you eventually want to be able to introduce them to new places and people, but at least until they’re trained, a predictable environment will be easier on them.
Desensitization and Counterconditioning
Your dog needs to unlearn their reactions to fear triggers. Desensitization progressively decreases sensitivity to that trigger by gradually intensifying exposure to the trigger until it no longer incites fear and the accompanying aggression.
Counterconditioning associates something positive with the trigger, gradually reducing the fear connection. Improved behavior is rewarded.
A Parting Reminder
Fear aggression in your dog is a big red flag for you to take immediate action to prevent danger. Unfortunately, for some dog parents, it may feel overwhelming.
If you understand yourself and your capabilities and understand the reasons for your dog’s aggressive behavior, you can make wise decisions that will get your dog the help they need. Whether it comes from you, a professional trainer, or a combination of the two, effective training will help your dog become happier and more confident.