sudden agressive behavior

Question
I have a 17mo. old Boxer who has suddenly become aggressive and fighting at the dog park. She is fine for the first 30 minutes and then seems to want to get in skuffs with dogs, even BIG ones. She has been fine at the park up until lately. Time outs don't seem to work.I have read some discussions on this. I am leaning towards this being an adolescent spell that hopefully she will out grow. Next Vet visit will include a thyroid panel also. Do you have any suggestions on how to train her out of this? She gets exercise daily as well as the park 2x a week.

Answer
It's funny you mentioned "even BIG ones" because a lot of people don't know that all dogs do not see "size" and do not know they are smaller than another dog. That's a fact.

So size doesn't matter when a dog is aggressive toward another.

There are different kinds of "aggression."

There is the growling and barking while backing up aggression which is insecurity aggression. Also it is a sign of nervousness and a highly excited state of mind from insecurities.

There is the barking and not moving aggression that is a sign of wanting attention and/or thinking they are doing what they are supposed to do; protect their owner and family- their pack. It is a warning alarm.

There is the snooping around another dog, sniffing and smelling, and introducing themselves, and an attack comes on when the other dog does not want to engage any further and sends that signal (they sense the state of mind and being; their smell and stance, etc.) and then the dog will get into a scuff to show dominance and that he or she is not afraid. Sometimes it is a bluff, and sometimes it isn't.

I sounds like your girl is not socialized well as yet.

The reason she had not behaved this way previously is due to being more "puppy" with playing in mind, and not finding her adulthood position in a pack.

At a dog park, there are a number of dogs which creates a pack.

Dogs that go on a regular basis have become friends by accepting one another into the pack and know their own limitations and boundaries with each other... what is acceptable and what is not acceptable behavior.

Your girl has not adhered to the rules of acceptable behavior in the pack. She is over-stepping her boundaries and being "rude." The other dogs will not allow that and fights can begin in order to keep her in her place within the pack of social behavior.

I would suggest putting a harness on her with a leash and taking her to the dog park. This is a "supervised" visit in order to teach her the social rules within the pack at the park.

Walk with her where ever she wants to go, and allow her to introduce herself to another dog by smelling and circling one another as they greet and become familiar. If she growls and becomes aggressive, pull her back and command her to sit.

Each time she behaves wrong in this social situation, get her attention as Cesar Millan (The Dog Whisperer) suggests with a touch or a shush-sound, and remove her and make her submissive. If you can, forcibly make her lay day into a submissive position which will put her mind into a submissive state.

She will learn to be submissive when another dog tells her to leave him alone, and soon, she will learn the acceptable way to socialize.