top of page
  • Shelly Gonzalez

Five causes of aggressive behaviors

What causes a dog to display aggressive behaviors or to react intensely to a situation?? It's their breed, right?? ::Sarcasm:: No! It's not. Below are some common reasons a dog may display aggressive (reactive) behaviors. *If you notice a sudden change in your pups behavior, a visit to the vet should be high on your priority list.*

*Do I have to say it? A dog displaying aggressive (reactive) behaviors doesn't mean she's a bad dog. It doesn't mean she's a danger. You and I have shown aggressive (reactive) behaviors at some point in life and it doesn't make us violent criminals. These are **behaviors** that your pup is using to communicate. It's your job to try to understand what your pup is saying and how you can best meet their need.

1) Illness

Have you ever gotten sick and been a bit cranky? The same is true for our pups. There is such a close link between illness and behavioral changes that *any time* I see a significant change in one of the pups at daycare, I immediately suggest to their parent that they set up a vet visit. Aggressive behavior may be your pups way of letting you know that they're feeling under the weather and there could be something more serious going on. If aggressive behaviors are a new issue with your pup, see the vet to make sure they're healthy!

2) Pain

Along the same lines as illness, being in pain can also cause some aggressive behaviors. This is important to remember if you're approaching an injured animal or if your pup has suffered an injury. A dog can't tell us "my left leg is hurt, so be gentle," but they still want to protect themselves. It's easy for us to accidentally put too much pressure on an injury or move a dog in a way that hurts them, and they may respond with growls, snips, or bites. If you do want to help an injured dog, it's not a bad idea to muzzle them first and be sure to be careful.

3) Fear/ Anxiety

Often times, if a pup is afraid of something they will attempt to remove themselves from the situation. If they're not able to escape they may turn to behaviors designed to keep the scary thing away. Fear may be specific "I'm afraid of that man in a hat," or it can be more prolonged, like the anxiety of moving to a new house or having a new family member. Some pups develop life long fears due to a frightening experience during the fear impact developmental stage. If you have a pup under the age of 2 years or are thinking about getting a puppy, it's worthwhile to do some research on their developmental stages. If your pup is showing aggressive behaviors and you think it's due to anxiety, work on helping your pup feel comfortable and confident. Remember, changes can impact them but they don't have the advantage of being able to have a conversation with us about how they're feeling.

4) Learned behavior

Another issue with fear based behaviors is that they can lead to learned aggressive behaviors.

Let's take fluffy. Fluffy is scared of unknown men. Fluffys human brother, who has been off at college, comes home, and Fluffy runs to the other room. Now Fluffys mom goes to get Fluffy so she can "show her that brother is nice," and in the process she forces Fluffy into brothers arms, or she leashes fluffy and walks fluffy over to brother. Fluffy is scared and unable to get away from the scary thing. What does brother do?? He kneels down and moves towards Fluffy to pet her and prove his friendliness. What does Fluffy do when this scary thing is coming at her?? She snarls and nips at the air. Brother backs up. Fluffy has learned that snarling and snipping makes scary things back up. If this happens enough times.... Fluffy has now learned that aggressive behaviors will get her what she wants.

Please, don't force your pets into scary situations to show them that it will be OK. They're only learning that it ISN'T OK and that you aren't protecting them from the scary thing. A pup should not need to display aggressive behaviors to have their needs met.

5) Protection/ Resource Guarding

Some pups guard resources. A resource can be anything- their space, their person, their food, their toy, a blanket, a bed... if a pup finds something to be valuable, they may want to guard it. If your pup is showing guarding behaviors, seek out a professional! Please DO NOT attempt to punish your dog for their behavior, "teach them who the boss is," "dominate" them, or respond with aggression. Your pup has something that is so valuable to them, for whatever reason, they're displaying aggressive behaviors. For whatever reason, the threat of losing that item is a big deal to your pup. Hurting them or being confrontational is NOT going to help them learn to trust or to feel safe.

As with any behavioral change, you should see your vet as soon as possible. Once your pup gets cleared medically, it's important to seek out a trainer to help with modifying aggressive behaviors. Our pups are always learning and if they receive the message that their unwanted behavior will get their needs met (whatever that is- the scary person going away, their space, their toy) it's going to reinforce that behavior. Be sure that you're looking for a trainer who has experience working with reactive dogs and who approaches them with positive training methods. Using fear based training or punishments can exacerbate an already difficult situation. Ask around for referrals and don't be shy about interviewing the trainers. Your pup needs you to advocate for them and you shouldn't ever be afraid to ask someone who is providing a service for your pup some difficult questions. Ask for accreditation, google the name of whatever certificates or schools that they went through- do your research and your pup will thank you!!


Recent Posts

See All


bottom of page