Today I took Bevo to play at the dog park. We were there for a little over 2 hours, and he had his hackles up the entire time. He showed no aggression towards any of his playmates, he bowed to invite play, he played fetch with about 15 other dogs without incident, but his hackles up throughout the visit. It's bad enough that most people don't want a doberman playing with their dog, but when his hackles are raised, it is even worse. Any ideas as to why his hackles were raised for that long? Does this mean anything that I am missing?