Why Your Dog “Loses It” When You See Other Dogs on Walks

Reactivity
2 min read
May 13, 2026
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Bianca Barlow
Founder, Dogfulness
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If you’ve ever been out for a walk and suddenly your calm dog transforms into a barking, lunging whirlwind when another dog appears, you’re not alone. This is a super common behavior known as leash reactivity, and it can be confusing and frustrating. Let’s break down why it happens and what’s really going on in your dog’s mind.

1. Frustration

Leashes can create tension — both physically and emotionally. Many dogs have learned that seeing another dog usually means play, excitement, or stimulation. When they can’t reach that dog because of the leash, their brain starts associating other dogs with intense feelings, which can come out as barking, lunging, or pulling. Basically, your dog is frustrated and trapped by the leash.

2. Fear (Even When It Looks Like Aggression)

This one surprises a lot of people. Many leash-reactive dogs are actually saying, “Please don’t come closer.” On leash, dogs can’t create distance on their own, so their nervous system can shift into fight mode. What looks like aggression is often your dog’s way of protecting themselves because they feel trapped.

3. Lack of Impulse Control and Focus

Walking politely on a leash doesn’t come naturally to most dogs. It takes training, exposure, and practice to teach your dog neutral behavior when passing other dogs. Without these skills, even a confident dog can become reactive when they feel uncertain, excited, or overstimulated.

One Important Note

Leash reactivity is rarely caused by just one thing. It’s usually a combination of factors — fear and lack of skills, frustration layered on top of insecurity, or something else entirely. For the sake of this post, I kept it simple and manageable. But if you love going down behavior rabbit holes with me, stay tuned for more 💛

"Bianca truly gets to the root of the problem."

"Hands down, Bianca is the best and most experienced dog trainer on so many levels--she's more than a trainer--she truly gets to the root of the problem. We've worked with several trainers over the years, and we've never had one with such an incredible disposition and strong animal behavior acumen. Her feedback, tips and overall approach made everything feel achievable. The analogies Bianca uses truly help things click—we finally understood the why behind the training. We've always felt overwhelmed by dog training in the past, but this was easy to grasp, practical, and made complete sense. She's made our home of four dogs much more pleasant and calm!"

Tara Burke with Penny, Malinois Mix, and 3 Boston Terriers (Behavior Mod.)

"Bianca truly gets to the root of the problem."

"Hands down, Bianca is the best and most experienced dog trainer on so many levels--she's more than a trainer--she truly gets to the root of the problem. We've worked with several trainers over the years, and we've never had one with such an incredible disposition and strong animal behavior acumen. Her feedback, tips and overall approach made everything feel achievable. The analogies Bianca uses truly help things click—we finally understood the why behind the training. We've always felt overwhelmed by dog training in the past, but this was easy to grasp, practical, and made complete sense. She's made our home of four dogs much more pleasant and calm!"

Tara Burke with Penny, Malinois Mix, and 3 Boston Terriers (Behavior Mod.)

"Bianca truly gets to the root of the problem."

"Hands down, Bianca is the best and most experienced dog trainer on so many levels--she's more than a trainer--she truly gets to the root of the problem. We've worked with several trainers over the years, and we've never had one with such an incredible disposition and strong animal behavior acumen. Her feedback, tips and overall approach made everything feel achievable. The analogies Bianca uses truly help things click—we finally understood the why behind the training. We've always felt overwhelmed by dog training in the past, but this was easy to grasp, practical, and made complete sense. She's made our home of four dogs much more pleasant and calm!"

Tara Burke with Penny, Malinois Mix, and 3 Boston Terriers (Behavior Mod.)

"Bianca truly gets to the root of the problem."

"Hands down, Bianca is the best and most experienced dog trainer on so many levels--she's more than a trainer--she truly gets to the root of the problem. We've worked with several trainers over the years, and we've never had one with such an incredible disposition and strong animal behavior acumen. Her feedback, tips and overall approach made everything feel achievable. The analogies Bianca uses truly help things click—we finally understood the why behind the training. We've always felt overwhelmed by dog training in the past, but this was easy to grasp, practical, and made complete sense. She's made our home of four dogs much more pleasant and calm!"

Tara Burke with Penny, Malinois Mix, and 3 Boston Terriers (Behavior Mod.)
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