dog aggression in 2 dog household

Question
Having problems with the younger of the two dogs I have. The first, Sasha is a 10 yr old bitch, staffie/german shepherd mix and she has always been the sweetest dog in the world. I could leave her with a baby absolutely confident that she wouldnt hurt a hair on the babys head. She is a good dog. She was always top dog when we were out walking and would love to try and hump other dogs - but she never got aggresive...
Now enter Dakota - a 1.4 yr old Lab / springer mix who we got from a local famly who had 8 pups.... I live in the west indies so people dont treat their dogs great here and sure enough Dakota muct have been hit at some point in the 3 months from birth till we got her - becasue she is absolutely TERRIFIED of humans. She is fearless in every other respect but just so skittish and nervous if there are any people around other than me or my husband.... That we can deal with. And she has got better over the last year.... What we can't  deal with is her aggression toward Sasha. 5 or 6 times in the last year Dakota has attacked Sasha. Just before it happens she gets this spooky glazed look in her eye - 1 time just before it happened I actually saw Dakota stalking Sasha and then BOOM suddenly she has sasha by the ear and the scary thing is SHE WONT LET GO - A couple times we had to kick her and punch her (sorry guys this was the only way to help poor sasha) btu SHE STILL WOULDNT LET GO!!!! Finally she does and poor sasha scuttles off - She has drawn blood a couple times. Ther is never any warning - no growl or anything.
So, I know why this happenning but just not sure what to do about it! It is for sure a jealously / attention issue  - The reason I am writing today is becasue it happened again last night. I was giving dakota cuddles out on the balcony and as this was happening my husband called sasha out of the house for some cuddles. Dakota got up - my husband saw that look in her eye so he pushed her away from sasha but too late - she went for sasha again. It breaks my heart. I love Dakota but sasha is so sweet and doesnt deserve this! What can I do? Thanks so much ofr your help!

Answer
I feel your pain. I had a Dobermand and a Rottweiler that were wonderful. One day I was in the house and they had gotten on the bed, along with a few of the cats and a couple beagles. Usually there was no problem and everyone got along. There are pictures of them in my book and DVD.  Suddenly, a fight broke out between the two big dogs. I grabbed both of them by the collars, threw each in opposite directions, bellowed BAD DOG at the top of my lungs. The Doberman hit one wall and left a dog shape hole in the drywall, and the Rott hit the dresser. Both looked at me and slinked away.  That one action, the only time in nearly 50 years of dog ownership, I had to show who was the undisputed pack leader and I would not stand for the fight.
Now I am not saying throw your dog through the wall. It just happened that way when my arms went out with a dog at each hand. It was one of those "my kids under the car, lift the car and drag them out" and figure out later you weren't strong enough usually to do that.

The point is, the humans have to be the undisputed pack leaders. That means the dogs must have had successful obedience training.  We may never figure out what the trigger is for every aggressive/dominant encounter. The important point is to resolve it quickly, decidedly, and enforce the pack leader rule. If the dog is attacking a person, it is not seeing the person as a pack leader but a member of the pack or less. In wild life, the leader of the herd, pack, etc will be challenged by younger rivals for food, breeding, territory, "rights" to toys, affection, attention, and to reaffirm the ranking order. This does not go away when we domesticate an animal.

Domestication establishes an inter-species ranking and relationship. I.e. if you milk me I'll come by when I need to empty my udder. I'll retreive the bird, rabbit etc when you kill it and we share the food because you feed me, house me, protect me etcetera. We have established a contractual relationship. We remove the animals need to forage for itself, fight for itself in exchange for the "work" it does for us which may range from carrying cargo to guarding our house or being our companion.

When we introduce a new member there are several stages of the relationship. Friend or foe, threat or just adolescent playing, attention/resources sharing, (food, bed, territory, affection, toys, etc. This is not a static relationship. As a puppy gets older, the older dog will at some point let the new comer know it is not interested in playing, it wants to rest. Just as when we get older we get grouchy if we are interrupted, disturbed during activites or rest periods. We have adjusted to our surroundings to being familiar and unchanged and don't want the TV moved, don't want to part with an old sweater, chair etc.  

From your explanation it seems you have a teen trying to be active with golden years who wants to be quiet, undisturbed, etc.

Possible solutions: keep the younger dog away from the older dog or insure they each have a private "do not disturb" space. Make sure the younger dog has been obedience trained. Make sure both dogs see the humans as the pack leaders who are in control. If the older dog has been relying on you to keep the peace, the younger dog has not and feels it is the boss. When you catch them in the moment, you need to be firm and decisive. While physical force is usually a last resort, it may be necessary. Scold the younger dog. (NO! BAD DOG! etc) Support the older dog as "pack leader" (it was there first) {Fido, are you OK? let me see your paw, ear, pet it, openly love it. You are sending the message to the younger dog, don't mess with Texas, I love chili!) Send the aggressive dog to another area, room, where it can think about things (like a 4 yr old on "time out") When you bring them together again, make sure you show preferennce to the older dog and "warn" the younger/newer dog to be good or else. In terms of body language, I place myself between the dogs, with the aggressive dog in front of me and the other behind me. I move toward the agressive dog, I invade its space, I make it back up, get out of my way, something we do as part of obedience training when we teach sit stay, if the dog moves, you back up the dog by moving toward it and invading its space. Become a bigger advisary than the dog it is fighting with. "You want a piece of this, Huh? I'll show you who's boss" is the attitude you must provide.

We had a beagle (died of natural causes at age 18) that liked to boss the other dogs especially two of our Doberman dogs. The Beagle was the Alpha dog, was our first dog after we got married, long before the others came home and many times over the watch dog of the house vs the Rotts, Dobs who were only interested in guarding the couch. One day the one Doberman got tired and turned around and got the beagle by the throat. Our German Short Hair pointer ran over, nipped the doberman on the leg, the doberman dropped the beagle and as far as the dogs were concerned that was the end of it. Meanwhile I had to rush the Beagle to the vet for large holes in its neck, fortunately it was only skin and fur and not vital muscles, veins, arteries, nerves. We had 20 dogs and 10 cats at the time. After the Beagle died our large long hair black and white cat (Philo T. Farnsworth) became Alpha Dog and remains so to this day.

I hope this helps. Our Obedience training book and DVD are $29 post paid US ZIP if you want to read more about behavior problems and training and do it yourself vs using a local professional trainer.