This post contains affiliate links. Sites like Amazon and Chewy give us a small amount of $ if you purchase something using a link from us (at no extra cost to you).
We also run advertisements on the site. Please understand that the ads are randomly generated and we do not control which ads you see when.
Seeing your sweet, friendly dog suddenly turn into Kujo when he sees another dog through a fence or gate can be alarming, scary, and embarrassing! This is known in the “dog world” as barrier frustration, or barrier aggression.
Many dogs that exhibit this kind of aggressive behavior are otherwise social, playful pups! That’s exactly what we’re addressing in today’s Ask A Behavior Consultant. Here’s what one reader asked,
My dog attacks dogs at daycare or at the dog park only at the gate or entrance. It is very random and I feel as if he is territorial over the familiar places. In our apartment community he doesn’t bark at dogs or show any aggression in open space. We also take him to my moms or dads where there are more dogs and he is fine when in their space.
– Sincerely, Dog Park Police
This can be a tricky area. When I’m dealing with clients, I like to ask a lot of questions to get a clear understanding of the individual situation. For that reason, I do recommend that if you’re dealing with an issue like this, you seek the help of a professional behavior consultant or certified force-free trainer.
What Causes Barrier Aggression?
Let’s start from the beginning. Why is my dog acting aggressively all of the sudden, when five minutes ago he was happily playing with his friends? There can be a few different factors, sometimes combined. The primary two are often these:
- Frustration. For many friendly dogs, being restrained from saying hello can be super frustrating. This feeling of frustration can bubble up and intensity. That’s when it manifests as a big display of barking and lunging that looks anything but friendly! We also see this often on leash.
- Fear. Having a new dog enter your space (even if it’s not really “your” space) can be intimidating. Barking and causing a scene can be a dog’s way of trying to appear bigger and tougher than they feel. “If I scare the new guy, he won’t come mess with me!” he may be thinking.
For Dog Park Police, my guess is that the cause is a little of both. She also writes that the dog can sometimes be “timid around new dogs.”
It’s possible that this lab has learned that making himself big and scary to newcomers is a good way to avoid being messed with. It’s also possible that his excitement at seeing a new dog is getting mixed up with his nervousness about a potential conflict.
The combination of those two feelings is causing the explosion his owner is writing in about.
The Dangers of Barrier Aggression
Okay, so a dog blows up behind a barrier, but once he meets the dog face to face, everything is fine. What’s the problem?
Well, aside from the embarrassment that Dog Park Police is likely experiencing, there are a few other things that can go wrong.
- Escalation. For now, this dog may only be reacting when separated from another dog by a gate or fence. But as those feelings increase and intensify, there’s no reason why his behavior couldn’t escalate and appear in other situations. A big surge of adrenaline and cortisol in the brain doesn’t go away immediately. It stays in the brain and can influence a dog’s reaction later in the day. Maybe another dog bumping into Fido at the park is no big deal on most days. But if he’s already on edge and tense, it could become a big problem!
- Redirection. During an aggressive display of barking and lunging, our dogs are no longer using their rational, thinking brains. It’s not uncommon for a dog in this state to redirect these emotions on other dogs or people nearby. Dog Park Police writes that when this occurs, she grabs him by the collar and removes him from the situation. There very well may come a day when he blindly snaps at the hand grabbing his collar. This also presents a danger to other dogs that may be in the vicinity, which leads to our next point…
- Negative reactions from other dogs. Not all dogs take kindly to a dog that is barking, lunging, and growling. Although not directed at them specifically, some dogs take this behavior as a challenge. They could decide to start a fight with the dog making a ruckus.
For these reasons, I recommend the following course of action:
Step 1: Management
Management is the step we go to before training occurs. This means managing, or controlling your dog’s environment so that the undesired behavior does not occur.
Why? Because the more opportunities he has to rehearse the barrier aggression, the stronger that behavior gets. With time, these behaviors become habits that are harder and harder to change.
In this case, that means no more dog park visits. Dog Park Police writes that in some larger dog parks, these behaviors don’t appear. This may be because the fences or entrances are far enough away that the incoming dogs don’t feel invasive to her dog. If this continues to be the case, then those parks may be safe.
This reader also writes that her dog is happy to play with her parents’ dogs, when visiting their homes. In this case, more controlled playgroups may be his best bet for safe social time.
Step 2: Counterconditioning and Desensitization
This is where I highly recommend the guidance of a professional. Going through a counterconditioning and desensitization program to remedy barrier aggression requires attention to detail and careful planning. In this case, I’d recommend working at a park or somewhere with fences/gates during low traffic times.
With counterconditioning, we’re changing the feelings a dog has about something – in this case, a dog behind a barrier. We do this by connecting the trigger (dogs behind barriers) with something the dog loves – food!
We show the dog that each time the trigger appears, something delicious also appears. With practice, they begin to look forward to the appearance of what was once worrisome.
The important thing about this process is that the dog stays “under threshold.” By this, we mean we have to keep the dog within his comfort zone.
Every dog has a distance at which an upsetting trigger (dog behind a barrier) can be present and not so upsetting. That may be 10 feet or it may be 100!
Whatever the distance is, that’s the distance we need to work from. Remember, the goal is to NOT get to the point where any barking, growling, or lunging happens.
It’s important to rehearse this with a trusted trainer or good friend, and a very neutral, easy going “distraction dog.”
Set yourself up with your dog on leash at whatever distance is well within your dog’s comfort zone:
- When the trainer and dog appear, begin feeding your dog treats.
- As soon as they walk away, the treats stop.
- Repeat this several times.
- With several successes, you can begin closing the distance in small increments.
Keep these sessions short and sweet – don’t get greedy and try and push your dog too far. It’s better to have lots of little successes than to ruin a good session with a big explosion!
Step 3: Strengthen Your Skills
Changing the emotional response your dog has to the trigger that causes his barrier aggression is one very important piece of the puzzle. Next, you want to build some basic skills that will help you cope with this in more “real life” scenarios.
Because of the risk of redirection, and because you may not always be right next to your dog when someone arrives at the park, building a rock solid recall will be super important for your training plan.
For more tips on getting a rock solid recall in a high distraction setting like the park, check out How Do I Get My Dog to Listen at the Park?
Step 4: Putting the Pieces Together
Once you’ve spent some time changing your dog’s emotional response to the sight of other dogs behind a barrier or gate, and you’ve built a rock solid recall, you’ll want to begin putting both of those pieces together. Initially, this should still be in a controlled setting, with a trusted trainer or friend and an easy going “distraction dog.”
A good way to start is by using a long line. The distraction dog arrives, you call your dog back to you and heavily reward him as the dog enters the gated area. If all goes well and he is relaxed and comfortable, you can then release him to greet the other dog. If he seems tense, or reacts in any way, go back a few steps before trying again.
I’d recommend practicing this many times, with a variety of different dogs before going back into the “real world” and testing these new skills.
It may take some time and patience to get to this place. The good news is that with a dog that is otherwise happy, playful, and social, there are many other activities that you can enjoy together during the training process.
Tressa is a KPA certified dog trainer and writer living in Northern California. She specializes in working with behaviorally difficult dogs, as well as in addressing the challenges that often arise in households with both dogs and children. She works as the Canine Enrichment Coordinator at the Humane Society of Sonoma County, where she also teaches classes and workshops. She lives with her husband, their two dogs, and cat. When she’s not teaching or hanging out with shelter dogs, you can find her hiking with her dogs, or reading books.