DOG AGGRESSION

Question
I ADOPTED A 4 YEAR OLD AUSSIE NAMED MANDY AFTER LOSING MY MATHILDA TO CANCER. THUNDER IS MY 13 YR OLD  ACTIVE MALE. MANDY IS DEFINITELY THE ALPHA DOG AND GETS ALONG FINE WITH THUNDER.MANDY IS ATTACK AGGRESSIVE TOWARDS ALL OTHER DOGS YET SHE LOVES ALL PEOPLE.ON WALKS I HAVE TO BE VERY CAREFUL TO CONTROL MANDY WHEN WE PASS OTHER DOGS. SHE REALLY WANTS TO ATTACK OTHER DOGS.SHE HAS ATTACKED A DOG WHEN SHE ESCAPED THROUGH THE FRONT DOOR.I HAVE THE SITUATION UNDER CONTROL NOW THAT I KNOW HER AGGRESIVE BEHAVIOR BUT IS THERE ANY THING I CAN DO TO CHANGE THIS BEHAVIOR. I HAVE NEVER HAD AN AUSSIE DEMONSTRATE THIS KIND OF BEHAVIOR!

Answer
Hi Jane,
It's hard, just with what you have told me, to determine the reason for her aggression.  Many dogs are fine with family (including dogs) but believe others to be intruders.  It could be that, as a pup, she was well socialized to people, but not to other dogs.  Many Aussies are also territorially aggressive, and will want to keep the intruders from getting on to the property, a trait which was encouraged in the days when Aussies were farm workers.  They not only herded cattle, they protected the property.  Now, pet owners find this tendency objectionable, but it is probably safer to find a way to properly contain the dog, AND teach it to come when called and to "leave it".  I suggest you find a really good positive reinforcement class where you can learn how to teach her, and make those skills fluent.  When a dog goes into "attack" mode (most attacks are just ritualistic and designed to ward off a threat - the line is crossed when the dog does physical damage) you have about 3 seconds to issue your command and have the dog respond before it becomes too late (adrenalin or chemicals in the brain take over after that I suspect).
I have a book recommendation for you as well, to help you gain control on your walks: Emma Parsons' "Click to Calm".  The protocol is very clearly written, and it works very well if you train faithfully.  If your dog has bitten and done damage, acclimate her to wearing a muzzle in public for her safety as well as everyone else's, and don't worry about what anyone thinks;-))  The muzzled dog is the safest one at the picnic LOL.  I suspect that the other Aussies you know may have come from show lines, and this dog may have more of the original working temperament.  That's not to excuse the aggression or make light of it, just a comment on how things can go badly when such a dog does not receive good early training.  But, you can train an older dog not to be so "reactive" and to pay attention to you, rather than her surroundings.  Buy a clicker, grab some tiny soft treats, and get started with the attention exercise here: www.clickerlessons.com. If you need to find a trainer in your area: www.clickerteachers.net.  Because your dog is reactive, you should ask if the person gives "Feisty Fido" classes, or "Growlies Classes" as they are sometimes called.