dog aggression

Your Dog Training Questions: My Once-Friendly Dog Is Attacking Her Sibling

Your Question:


I have two female boxer/pit mixes. They are both one-and-half-years old and are sisters from the same litter. They have always been best friends. They have never had a problem with each other and were always cuddling and playing.

One of my dogs recently had surgery for a tooth extraction and a wart removal. Ever since she got home, my other dog has been violently attacking her. This dog has always been very submissive and never violent or aggressive.

It has been 3 days since the surgery, and we can barely even keep them in the same room without a fight. Have you ever heard of this, and what do I do?

My Answer:

All dogs have prey drive. That includes activities like stalk, chase, grab-bite, shake and kill. Typically domesticated dogs do not prey on and attack other domesticated dogs even though they may have high prey drives. Dogs living in the same household that have always been friendly could wind up fighting with each other when one of the dogs senses a difference in the other dog.

Perhaps after returning from a surgical procedure the other dog might appear “wounded.” This is where “predatory drift” can occur – that is to say that the dog drifts or “shifts” its prey drive normally reserved for animals outside its own species to another dog.

What to do? Control your home environment until you can work on reprogramming the aggressive dog. Keep both dogs on leashes in the house under your strict supervision. Do not set your now reactive dog up to fail by accidentally or purposely presenting her with an opportunity to become reactive. This will require an extensive evaluation of your home life structure with your dogs and their obedience training.

Once that is accomplished, behavior modification exercises need to be put into place to reprogram the reactive dog’s  view of your other dog. You should locate a good positive reinforcement trainer to help you with this task.

So, what is YOUR question?

(C) Jim Burwell 2010

4 replies
  1. leila_admin
    leila_admin says:

    Lucia: Jim wrote an article on sibling rivalry. Do a search for that on our site and there is good information on there and the ability to download a free 60 minute
    teleseminar on this subject.

  2. lucia marsalisi
    lucia marsalisi says:

    i had a similar situation w/my male do i reprogram the reactive dog’s view of the other dog that is now afraid of him because he attacked him twice and was hurt badly…he was also the “alpha” and feels “dethroned” now. i am keeping them separated and it has been almost 2 mos since the first fight

    thank you

  3. Lynne McKay
    Lynne McKay says:

    8 year old pugalier and 2 year old Kelpy – both females , best friends for 2 years now attacking each other viciously – both fixed, no change in house or dogs that we know of

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