german sheperds and aggression

Question
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Followup To
Question -
My german sheperd, Mac, is about two years old.  He has
been showing a lot more aggression lately on walks.  Just
yesterday he went after another dog and it took three
people, including myself to break them apart.   We have a
one year old little boy and Mac is great with him and our
friends.  It seems it's just strangers..... What can I do?  More
training?
Answer -
Hi, first I need a couple of questions answered, then I can possibly help you.  

Is Mac neutered?
How old was Mac when he first started showing aggression towards dogs?
I assume by your statement "It seems it's just strangers" that he is showing aggression
towards humans.  If so, when was his first aggressive incident?  If he has had more than one
incident with humans how often apart have they been and can you describe with as much
detail as possible what happened when the incident or incidences happened i.e. was his hair
raised, did he growl, was there food present, on your poperty or away from his territory, on
leash or off etc.  The more details you can give me, the better I can figure out what exactly
is going on in his head.  Also, what type of training has he had, how old was he and what
kind of methods were used i.e. equipment on him like prong collars, choke chains, head
halters etc. and was it reward training, leadership training or dominance training.  Let me
know and I will try to figure out what is going on with him and what you can do abou it.

Dawn

Dear Dawn,
Thanks for getting back to me.  As far as your questions, I'll try to answer them as best I
can.  Mac did have training for about a month when he was six months.  It was obedience
training (leash training).  Mainly to heal, sit, down, off etc.  He was trained at fist with
reward trining and then that was not enough so he now uses a prong collar,  which has
worked out great.  He is greeat on a leash, the problem is off leash.  Yes he is nuetered,
about six months old.  His aggression is towards people and dogs (strangers) it started
about six months ago, he is almost two years old.  He does not have food agression, we
made sure of that early on.  the incident I am writing about happened a couple weeks ago.  
It was in an enclosed teniis courts with four toher dogs, two Mac knows and one he didn't.  i
have brought him there many times before with other dogs to play and he has been fine.  he
loves chasing sticks.  I think the dog he went after had a stick, so I assume that was his
problem.  My concern is, what if it was a child with a stick?  He normally doesn't have
aggression towards humans, maybe at night when I walk him.  He growls, barks and his hair
stands up, as he did that day at the tennis courts.  I hope that is enough, I appreciate any
feedback you may have.,

Linda

Answer
Hi, ok first just to let you know, training with a prong collar is a form of dominance training.  This is a method of dominating a dog to get him to do what you want.  Mostly with prong collars people are doing it because of the size of the dog, but still in the mind of the dog, you are still dominating him.  
As far as natural aggression, he is at the right age for his natural protective abilities to start coming out.  Normally, in the wild, a dog will start to show their natural protective abilities around a year to a year and a half of age, so that is the good news.  Everything is normal as far as his age and being protective.  
The incident in the tennis court is what we call a "pack situation".  Whenever you have more than two dogs together and an aggressive situation occurs, it becomes a pack situation, sort of like a barroom brawl, one guy starts and the rest join in.  That type of mentality is not really what the individual dog is really like, but instead is what comes about from the pack mentality kicking in during the aggressive situation.  It probably was initiated by the stick (your dog probably has high prey drive) and it got out of hand).  Also, since he is a shepherd, some shepherds do have problems with other dogs, especially if the other dogs do not give into them.  Mac wants to be alpha to the other dogs, and if they don't give off body language immediately that they give in, then he becomes the aggressor to show them he is the alpha (another common trait in dogs who have been dominance trained).  
As far as humans, I think he is being naturally protective when it comes to humans in general, very hard to say what he would do if a person had a stick.  If you could find a local trainer who could test him with a decoy and see his reaction to a decoy raising a stick at him, you might get your answer.  We do a generalized temperment test like that in our training for some of the same reasons that you are dealing with.  Basically what you would want the trainer to do is have the decoy jump out from behind a bush or blind at you while the dog is at your side on leash, with a stick raised at you.  What you want to see is if the dog would go at the decoy or if he would stop and try and figure out what is going on.  If he just automatically triggers, then yes I would worry about him being around a child with a stick.   If you have anymore questions, feel free to let me know.  Hope this helps,

Dawn