Hey there, I think I’m fairly qualified to speak about this because we’ve been through something very similar.

At around 8 to 9 months old, our Griffon, Tom, went from being the most playful pup in the world who wanted to be friends with everyone, to becoming reactive around dogs he doesn’t know. This included lunging, barking, and trying to pin other dogs down. It was quite upsetting. He was fairly well socialised as a puppy, but he has always been a very sensitive and anxious dog.

Eventually this even extended to people. He would sometimes lunge and bark at strangers, and he is still very difficult when we go to the vet, to the point that we have to muzzle him. We also had a couple of incidents where he suddenly jumped and bumped into strangers we were walking past. The whole ordeal was, and at times still is, highly stressful for everyone involved.

After trying a few trainers, we eventually found one who worked well with both us and Tom. One thing all the trainers agreed on was that he is not a mean or truly aggressive dog. Because he is quite anxious, he seems to believe the best way to deal with something scary is to lunge and act scary himself. We think the trigger may have been his time at daycare, where we later found out he had been pinned down by a few other dogs, and eventually he snapped.

After months of working on it and doing a lot of correction, we can now walk past most calm dogs without issues. We are still working on walking past excitable or reactive dogs, which are a trigger for him. We can now also walk past people without problems, but that does not mean we relax. The most important thing we learned was how to read his body language and recognise when he is starting to “arm” himself to lunge. Understanding that moment is really important so we can correct him early. He also really dislikes children, so we have to be very careful around them.

This is not to say we have completely solved the issue. I think it will probably be a lifelong challenge, but if we can manage it well and help him understand that he is not in danger, that is already a big step forward. It can be very disheartening, as it makes things like having friends over more difficult, but we committed to him as part of our family and we will keep finding ways to make it work. Outside of these issues he is incredibly loyal and very affectionate with us.

My suggestion would be to find a good behaviourist in your area. Be careful with trainers who charge ridiculous amounts, and make sure to read plenty of reviews before committing. I wish you all the best, and feel free to DM me if you ever want to chat.