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Canine Behavior/Sister aggression


Hi Jill,
We have two dogs, one 3yr old F mix (maybe pitbull and hound), and a 2yr old F pitbull mix (they really aren't sisters, just housemates). After having them separated all the time for the past 6 months due to their aggression towards each other, we are trying to rehabilitate their relationship and get them back together. My husband and I have them on leashes and keep them by our sides and unable to reach other most of the time, and allow them play time together every once in awhile when we are able to give them our full attention. They will play nonstop if we allow it.  But we have these instances pretty often where out of nowhere the 3yr old will hate the 2yr old. She flips a switch and goes from loving her sister to hating her. They'll be taking naps while we watch tv (unable to reach each other), and she will wake up and give off tons of body language like "don't come near me or I'll kill you." The 2yr old can't handle this, and she immediately will try to attack the older one (although she's on leash some don't allow them to reach each other). These exact instances seem to come out of nowhere (no triggers like food, toys, beds, etc) and often, multiples times per day. It's really stressful and time wise it's very difficult to give 100% of our attention at all times. How can we handle these instances, correct them, avoid them, etc.? They are pretty obedient for the most part, but once they flip those switches and go into attack mode, it's impossible to regain their attention to get them out of the mindset that they need to kill each other. I appreciate your help so much! Thank you!

Bitch to bitch aggression of the sort you describe is almost always quite difficult to rehabilitate and you might inadvertently be making it worse.  Dogs don't "play" in the sense that we understand it.  "Play" behavior between/among dogs is a social interaction and yes, intended for (what appears to be, usually) joyful experience, BUT....huge but is also a test of social hierarchy.  One dog among several (or two especially) will be clearly (if one is reading body language) "in control" of the "play" and its ultimate result: possession of the toy, ball, etc.  One dog may offer another a toy (such as my Ibizan Hound used to for all newcomers into our household, and there were many as I did rescue work) but she was always, always, making a social statement of her "queenhood" in my household (although benign, she was a gentle giant who led with great dignity).  

The only way to determine if these two can ever live together peacefully (and I rather doubt it at this point) is to have an experienced behaviorist evaluate them, and your overall situation.  I have, in the past, rehabilitated serious aggression between dogs (males); females are far more difficult.  The use of a clicker can instruct the naturally subdominant dog that all gestures of subdominance are rewarding but, first, you have to be instructed (quite carefully) on how to condition the dogs (individually) to the clicker and then on how to read very subtle body language and reward appropriate signals.  This is a tricky business.

To find a certified applied animal behaviorist, see the following sites:

As for leashing one dog and not the other: very bad technique giving the wrong signals to both dogs.  As for allowing these two to "play": I would suggest that it doesn't appear to be working (from your report) and might be making things worse.  Walking parallel on casual walks, with two people (you and your house partner/mate or someone both dogs know very well) is one way to decrease tension but you cannot, under any circumstance, leave these dogs alone together.  The six month separation you speak of might have worsened the problem but I can't see anything from here and I'm not making any predictions.  I can't even advise you ethically because I can't see what's going on between these two.  Find a CAAB as soon as you can.

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Jill Connor, Ph.D.


I have spent my entire professional life rehabilitating the behavior of the domestic dog and I can answer any question regarding any behavior problem in any breed dog. I have answered more than 5,000 QUESTIONS on this site in the past (almost) eight years. If you are a caring, committed owner and need advice, I'm here for you. I am personally acquainted with my colleagues (Turid Rugaas, Ian Dunbar, etc.) who were members of an elite group in EGroups that I founded: K9Shrinks. THERE ARE NO QUICK FIXES for serious behavioral issues; not only is it unprofessional to offer same, it is also unethical. IF I ASK YOU SUBSEQUENT QUESTIONS, I NEED YOU TO INTERACT WITH ME. More information equals more credible answers and a more successful outcome. If you want ANSWERS THAT WORK, participate in any way I request. I'm quite committed to working on this site for YOUR benefit and the benefit of YOUR DOG. Help me in any way you can.


30 years of solving serious behavior problems in domestic dogs; expert in dog to human aggression; Internet columnist for for 5 years; former radio talk show host, WHPC.FM, Garden City, NY "Bite Back" (1995 through 2000). List owner, international animal behavior experts, Seminar leader: "Operant Conditioning and Learning"; "Aggression in The Domestic Dog"; "Solving Problem Behaviors" -- conducted for various training facilities on Long Island from 1993 through 2000. Former clinical director of "Behavioral Abnormalities" in conjunction with Mark Beckerman, DVM, Hempstead, New York.

Member, APDT (UK); Psychologists in Ethical Treatment with Animals

Harcourt Brace Learning Direct: "The Business of Dog Training" "The Fail Safe Dog: Brain Training, not Pain Training"

Ph.D., UC Berkeley

Past/Present Clients
Board of Directors: Northeast Dog Rescue Connection; The Dog Project; Sav-A-Dog Foundation; etc. Pro Bono counselor: Little Shelter Humane Society My practice is presently limited to forensics. I diagnose cause of dog bite, based upon testimony before the Court, for attorneys and insurance companies litigating dog bites, including fatal injuries. I also do pro bono work for bona fide rescue organizations, humane societies, et al, regarding such analysis in an effort to obtain release for dogs being held for death in municipal shelters in the US.

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