Malu is about 9-1/2 months now and he is exhibiting agression towards a specific dog. Here is the backstory.
My My mother and I walk malu and the 7 year old family springer spaniel to the local bike path/recreation fields. Once into the open area and away from the road many of the dog walkers let their dogs off leash to run and play. Malu has had a great time and behaved well with other dogs when we let him off. On two seperate occasions we have run into a golden retreiver puppy (8-12 month old) when walking to the park area (on leash). On both occasions the golden will lay down and stop in its tracks ( I have no idea why). Malu for some reason gets very agressive and will pull towards the dog and growl and show teeth. I have never seen him do this to any other dog or in any other scenerio.
Today, while i was away at work, my mother decided to take Malu down to the park with her. She let the dogs off and my mom wasn't aware that the women and the golden had entered the park area. Malu noticed the dog and ran over "attacked it". I am not sure in what manner he attacked the other dog but a friend of my mother was able to seperate the dogs very easily. His comment to her was that he thought if he was really trying to hurt the dog that he would have probably gotten bit when he stuck his hand in there to seperate him. No harm was done to the other dog but the owner was quite upset.
Any idea what could be causing this behavior? It seems like he may be trying to assert his dominace with a younger dog. Hehas an appointment next thursday to be neutered, maybe this will help. I am mostly dissapointed that I can no longer trust him off leash with other dogs.
Thank you for any advice,