Hi. I have a 3 yo lab mix who is the most gentle dog I know. She has always been great the dog park, doggie day care, and with other people.

Recently a friend got a boxer puppy (now 6 months) who likes to play aggressively (i.e. box, wrestle, mouthy) with my dog. Normally my dog does not like to play aggressively with other dogs. When they go to the dog park together, my dog becomes a mediator in an aggressive way. She starts breaking up play-fights by chasing down certain dogs that she sees as a "problem". To do this she will bark, body-block other dogs, nips at their necks, and tackle them into submission whenever they get near her boxer friend, or even other unrelated dogs who are at play. Her posture is tail high, ears forward, and sometimes the hair on her back/neck stands up. She doesn't seem to do this when her boxer friend is not around. Is is this overly protective behavior, or is my dog learning to play too aggressively from the boxer puppy?

Thanks for your thoughts.

Hi, kkerr.

If your dog is doing this only while the boxer is around and your dog is showing piloerection (hackles up), a braced-forward stance, ears forward, etc., your dog is not "playing" aggressively. Dog's can play aggressively, but a dog that is exhibiting the type of body behavior you described is showing a sign of discomfort.

If she's not doing this while the other dog is around, I'm wondering if maybe your dog is just being over-protective or if she's resource guarding her friend from other dogs. How is she with other things? Is she protective around her toys, food, etc? Does she exhibit normal play behaviors around other dogs when the boxer isn't there, or does she keep to herself? Does this happen only at the park, or does it happen on walks as well when other dogs get close to them? Has she always reacted this way around the boxer or is it something that just started happening?

You may want to contact an animal behaviorist to see what they think of the situation. They can help you assess what is going on and work out a solution. Check with your local animal shelter to see if they have one on staff (if you have a SPCA or a Humane Society, they may have one). Some consults can be a quick, free phone call. Others can be one or several visits (price ranges, but it's about $25 an hour in my area.) Sometimes, it's necessary to see first-hand exactly what is going on (especially right before it happens, after it happens and how all the dogs involved react).

Sorry I couldn't give more advice but I hope I've helped a little bit.

Thanks for the reply, DaGracer.
Subsequent to my last post, I took my dog to the dog park without the boxer puppy. While she was much more relaxed, she still started to get rough including frantic chasing behavior with barking, and pinning more submissive dogs to the ground. Her posture was similar - tail up, ears forward, forward stance, but no piloerection. I left the dog park as soon as I saw this behavior.

To answer your other questions, she does not seem to display aggression towards objects or territory, and she is very friendly to all dogs and people on walks. She has never been at all aggressive until she started hanging out with the boxer puppy. As the puppy has been growing, my dog has had to become more aggressive to fend off the boxers' constant provocations (intended to get her to play).

We just started obedience class, so I'm hoping that will help. I'm also thinking about contacting an animal behaviorist so we will be welcome at the dog park again. Thanks for the suggestion where to find a professional.