I took Jack to the dog park for the first time Sunday. When we got there, there was a lady and her loose ACD in the parking lot. I asked if he was friendly and she said "Yes." I let Jack out of the car to meet him. Jack was being VERY polite to this dog when greeting--his head was low, his little tail was down and wagging, and he politely sniffed him. Almost immediately, the ACD stated to growl. The lady just said "oh, he's OK--Shep, don't growl, he's just a baby."
I decided to just try to get Jack moving (I've been told not to pick him up when another dog growls at him) but the dog kept at it. He was growling and kept trying to stand over Jack, even as I was trying to walk him away. His owner, still about 10 feet away said "Oh, sometimes he's protective of me, maybe he senses he's a male..."
Jack rolled over on his back. The ACD jumped on top of him, snarled, and started biting his face! Finally, the owner is like "Oh, now he's being aggressive, I don't like that Shep," and meanders her way over to the ACD, who is STILL on Jack and biting him, and puts him on a flexi. After Jack and I started making our way down to the park he came after Jack AGAIN--but couldn't reach him with the leash on.
I have been told that older dogs will put pups in their place, but this seemed like more than that to me. Am I just being over-protective? What should I do if that happens again?