My parents Great Dane bites

Question
QUESTION: My parents have a 7 year old female great Dane.  She has always been good tempered until the past year.  It is getting worse, she has bitten my brother twice.  Last week my sister-in-law was over and the dog was on her chain.  Lucy went over and spoke to the dog and she was fine, wagging her tail, I was standing next to the dog.  Then out of the blue she took off after Lucy, thank goodness the chain stopped her but not before she got a hold of the lower part of her jacket.  There were two places the dog had bitten the jacket.  Now I am a little scared of the dog after seeing her go from fine to vicious.  Should I worry about my parents, daughter and my own safety around this dog?

ANSWER: Yes,it is very dangerous to keep a dog chained because they becoem very aggressive. You need to consult with a trainer in your area immediately to try and nip this problem in the butt before it becomes too serious.
visit www.dogsdeservebetter.org for more on chaining dogs

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QUESTION: The dog is only on a chain when it is let outside to use the bathroom.  My parents sleep in different beds because the dog sleeps with my dad.  She is very humble toward them and is even scared of thunder storms and the dark.  My problem is the aggressive behavior toward my brother at times and other animals plus strangers.  My question was concerning her behavior toward the ones she is use to and begs attention from.  Could she snap and is it common?  She it my brother once when he tried entering the house when my father wasn't home.  The dog is very protective of my mother and maybe to much.  The other time she bit him he had been in the house for awhile talking to my father.  My mother and I were in the back room, when my brother turned the corner she started toward him growling and barking.  My brother called her name but she still advance and got him in the stomach.  Other times she is fine with him and his two boys ages 8 and 11.  They stay over all the time and the bog adores them.  I am fearful she will brake her chain while outside and attack someone in the neighborhood.

Answer
Your concerns are very valid, all those things could potentiall happen so you are right to be afraid. It sounds like there is some confusion about where she is on the totem pole,she seems to think she's right up there at the top with your parents and the rest of you are down below soemwhere. You need to get a trainer or behavior expert in there quickly before things get worse, with such a big dog you don't want to take any chances,she could do alot of damage with very little effort. You could apply to have Victoria Stilwell from the show 'it's me or the dog' help you which I think would be the best thign to happen to that dog,or you can search for trainers in your area. To apply for the show you can go to Animal Planet's website.But you definately need to act quickly before she gets any more out of control