Why Is My Dog Aggressive to Bigger Dogs?

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Some dogs get along well with other dogs their size, but are aggressive towards dogs bigger than them. This pattern is most common in small dogs, but you can find examples in all sizes of dogs.

My own dog, Barley, is much more tense with giant breed dogs like Great Danes and Wolfhounds. Barley isn’t a small dog – he’s almost 50 pounds – but huge dogs make him tense.

If you’re struggling with this problem, you might want to also check out these Journey Dog Training resources:

Why is My Dog Aggressive Towards Bigger Dogs?

The short answer is that we really can’t know, because we can’t ask your dog. But here are some likely reasons why:

  1. Bigger dogs are scary, just like bigger snakes, spiders, and crocodiles are scarier. This is true for small dogs scared of medium-sized dogs, and medium-sized dogs scared of large dogs. If you’re the little guy in a situation, it’s normal to feel threatened by the big guy. And the best defense is often a good offense – so the scared little guy puts on a big display, which makes the big guy back up. And ta-da, your dog just learned to behave aggressively in order to make scary big dogs go away.
    1. (Note: this doesn’t mean that ignoring your dog’s warning signs is the answer – we’ve got to teach your dog that big dogs aren’t scary, not that behaving aggressively doesn’t work).
  2. A big dog might have scared or hurt your dog. Sometimes, your dog isn’t just scared of big dogs because he’s intimidated – he’s scared because he had a bad experience! If you already know that your dog was hurt or scared by a big dog, then that explains things.
  3. Stress can travel down the leash. Let’s say I was scared of German Shepherds after a scary experience with a police dog (or a Pit Bull after reading a news story, or a Labrador after one knocked me over as a kid). Later, I see a German Shepherd (or Pit Bull or Lab) on a walk with my Maltese. I tighten up on the leash, my palms start to sweat, my breathing quickens, and I pull my dog a bit closer to “stay safe.” My dog notices and gets tense too. The next day, the pattern repeats but this time my dog growls a bit because Mom is really worried! The third day, my dog growls again but this time I scold him. The next day, he sees the big dog and is REALLY worried – Mom was scared of him, and yesterday she yelled at me when he came close! Gosh, I’d better be sure to keep that big dog FAR away! And there you go, now my dog is scared of big dogs because I was scared of big dogs.

It’s pretty common to have a few questions if your dog is aggressive towards bigger dogs. Let’s tackle those with a quick Q&A:

Is It Small Dog Syndrome?

Well… maybe? What IS “small dog syndrome?” It’s certainly not an actual diagnosis, the way hypertension syndrome or major depressive disorder is.

My personal inclination is that small dog syndrome doesn’t really exist – it’s just a name people give to the pattern of fearful behaviors commonly exhibited by anxious, undersocialized small dogs.

These little dogs are predisposed towards being nervous of big things – aren’t you more scared of a lion than a cheetah, or a cheetah than a house cat? When you’re little, big things are scarier.

But this problem is worse when the owners fail to help their small dogs learn that big things aren’t scary. The owners don’t expose their dogs to scary stuff and/or don’t teach their little dogs that scary stuff = treats.

Exposure isn’t enough here (read all about that here). Your small dog needs to learn that other dogs are actually safe to be around, and that takes work!

Can an Aggressive Dog be Cured?

Oh, gosh. The never-ending question in my field. All behaviors are modifiable. And we can always do something to make things better. In many, if not most, cases an aggressive dog can improve enough to be “good enough.”

But you can never really guarantee that ANY dog will never behave aggressively. We can’t even make that promise about humans!

Treating an aggressive dog will require a combination of management, counter-conditioning, and training the dog to do something else when he feels tense.

Punishing your dog for behaving aggressively will not help in the long run.

That’s because aggression is generally caused by a negative emotion, and punishing your dog will only make him feel worse about other dogs. While popping his collar or smacking him on the butt might interrupt the bad behavior, it won’t stop him from doing it in the long run. Worse, it might suppress warning behaviors (like lunging and growling) so he “looks better,” but then he skips straight to biting if a dog gets too close. Yikes!

Is My Dog Being Alpha?

Owners who see their dog being aggressive towards other dogs often think that their dog is trying to assert his dominance, prove himself to be alpha, or put the larger dog in his place.

To be frank, there’s no evidence that this is the case. The studies that led to scientists thinking that wolf dominance structures were strictly hierarchical and enforced through violence have been debunked.

And let’s be honest – dogs aren’t wolves. They don’t behave the same way at all. They’re much more similar to wolf puppies, even when they’re fully mature.

So your dog might be a jerk to bigger dogs, but it’s not because he’s trying to assert his dominance.

Dominance does exist in dogs – but it’s a specific relationship between two individuals in regards to a given resource. So rude behavior between two stranger dogs isn’t likely to be related to dominance.

Ok, So How Do I Teach My Dog to Stop Being Aggressive?

There are a few things we need to do in order to begin to change your pup’s aggressive reaction towards other dogs.

1. Manage His Environment

In order to be successful, we need to manage your dog’s environment so that he is never feeling threatened, overwhelmed, or feeling as though he needs to defend himself from bigger dogs.

2. Avoid Punishment When Your Dog is Scared

Sometimes after a bad experience, it’s not just our dogs who behave differently — sometimes we also change our behavior!

In order to control a bad situation, people often resort to yelling or tugging on their dog’s leash when they are in a precarious situation. Sometimes people feel they need a harsher tool such as a sock collar or pinch collar to control their dog’s behavior. 

These tools and strategies actually make matters worse. They can make aggressive behavior worse, and cause your pup to become more fearful. 

Your dog is feeling worried or anxious, and it’s ok to comfort him.

The aggressive reaction he is expressing towards other dogs is not intentional, it’s reflexive.

He is worried and is trying to tell that other dog to go away. It’s ideal to help him to avoid these situations and to look to you for support.

3. Change His Opinion About Other Dogs

There are a few strategies we can use to help your pup cope with seeing another dog:

  • Desensitization. In low, slow doses, expose your dog to big dogs without any reaction from him. If it looks boring and it looks like nothing is happening, you’re doing the right thing! Exposure to other dogs without any reaction or feelings of anxiety can help your dog overcome her fears. You might have to start 50+ feet away, then gradually move closer.
  • Counterconditioning. This, when paired with desensitization, can help to rewire your pup’s brain. When he is in the presence of another dog but isn’t reacting in any way, feed him some tasty food. When we pair the trigger (dogs) with delicious snacks, we can change his reaction from something negative to something positive. When he sees another dog, he begins to predict a treat. 

I highly recommend a positive trainer or a behavior consultant to help you with this process. They can help you get started and assure your timing of treat presentation is perfect!

4. Practice Makes Perfect.

Practicing these tactics once or twice a week isn’t going to get you very far very fast. It takes patience and perseverance! Even if you get out to practice for 5 minutes twice a day, you’re doing great!

Try to keep the sessions short and sweet. Sometimes the first or second big dog you see on a walk is tolerable, but anxiety begins to build and the third, or fourth dog your come across put your pup over his threshold. Be sure to keep things short and sweet, but get plenty of repetitions in!

9 thoughts on “Why Is My Dog Aggressive to Bigger Dogs?”

  1. Hi Kayla! This is a really well written article on dog aggressiveness, I actually learned a thing or two and that part where you mentioned stress can travel down the leash is true! I had a similar experience when walking my dog. A bigger dog escaped the leash and ran towards me (almost bit me) and I freaked out and almost hurt my dog – Think it caused a somewhat kind of trauma to my dog

    Just wanted to get your opinion on something – I was just reading this article about training an aggressive dog over https://doggiely.com/training/how-to-train-stubborn-dog and the guy mentions that one should use a firmer tone when a dog is not responding to commands.

    Would love to know what you think about it if it would not p*ss off the dog? Thanks! Can’t wait to hear your reply as I have a dog that’s constantly frustrating me and don’t want things to go worse

    • Hmm, sometimes being louder can “cut through” distractions – but it can often escalate stress or even lead to you yelling more and more over time. I’d focus on helping the dog learning that listening to you is worth it by slowly increasing distractions, with lots of rewards, rather than trying to intimidate or shout the dog into listening! 🙂

  2. Hello! This is a well-written article on the dog’s aggressiveness. Thanks for sharing some important things that we need to do to change the Dog’s aggressive reaction with other dogs. We’re also one of the leading companies in the USA and provide top-quality dog training. Visit us at https://balancedpackk9training.com

  3. My mom’s friend’s cockapoo gets aggressive with golden retriever sized dogs and would start to growl and bark aggressively. How do I train that aggression out of him? His behavior prevented me from bringing him to dog parks with larger dogs.

  4. Hi Kayla!
    I have the same issue. My German Shepard pitbull mix does not like bigger dogs, with deep loud barks. We recently brought home a puppy assuming he would be great with her because she’s smaller, and they are great together! But now my worry is, is he likely to change how he feels about her once she gets bigger? She’s a yellow lab so she will be big. Will he snap and become aggressive since she’s bigger? Or not because she grew up with them and there’s a relationship there? I am worried about that happening. What are your thoughts?

    • Hi Mackenzie, unfortunately it’s SO hard for me to predict right now. I’d definitely keep a close eye on their relationship as they both age. It’s possible that they’ll be fine, but especially as the puppy hits 6-12 months old, keep an eye out for any tension in their relationship and let us know if we can help!

  5. To the lady with the German Pittand lab female! It is early to predict as the writer stated however, the early introduction is key! They will build a trusting relationship! Have them walk together, eat together with appropriate supervision and explore areas together under supervision. This activity can bond them. My dog sometimes can be wary of larger males, he is a rott/Pitt and not fixed as he is still a puppy. That being said, he does love a large male that is calm and confident and will challenge him in play. (The right dog will even hump him if needed!! ) It sometimes just takes the right matches.My dog has played really well with same size or way larger , same sex unfixed males that are trained and confident. He has also been attacked by large breed males who are also scared of large breeds that aren’t so confident and aren’t so well trained. I think your dog, with your continued support, will love having a playmate he can wrestle and chase.


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