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Canine Behavior/dog fighting


(sorry I previously left out part of question-like the question)

How can I get my dog Gavri to stop what appears to be unprovoked attacks on other dog atlas.

I currently have three dogs.  Romeo a 17 yr old neutered Chow mix, Gavri a 15 month old Great Dane neutered 3 days ago, and Atlas a 13 month old Great Dane also neutered by the rescue he came from at 5 months old.
Romeo is definitely the dominant dog in the house, the other 2 will submit to him, rolling to their back when he growls, and neither will approach him while he is eating and he has taken food from their bowls while they were eating without a response (altho I do not allow him to since I caught him at it).
Gavri and Atlas have always gotten along well, even sharing bed until 2 weeks ago.  Then Gavri viciously attacked Atlas (unprovoked that I could tell).  When not separated Gavri now will play with Atlas but out of nowhere will become aggressive and attack.  This only occurs at home (indoors and out).  When walking on a leash or off leash in woods there is no aggression.  Atlas has become very submissive to Gavri, licking his face and offering his backside to him.  At the time the attacks started Gavri was intact male.  Got him neutered 3 days ago.  Atlas was neutered by rescue prior to my getting him

Thank you for your question. Aggression between housemates can be frustrating, scary and dangerous.

The first order of business whenever there is a sudden change of behavior is to get a complete medical exam. This should include a full blood panel - including a complete thyroid panel (the kind they ship out to Cornell University's lab or Dr. Jean Dodds at Hemopet . Dr. Dodds is the foremost expert on canine thyroid issues and will run the full 6-panel test and provide a proper interpretation of the results to your vet. Both hypo- and hyperthyroid can affect behavior in many ways including with increased aggression. Left untreated, the behavior problems can escalate while the rest of the dog's health declines.

So, we always must begin by ruling out pain, illness, disease or condition as if it is one of these medical issues, then treating the medical issue will most likely resolve the behavioral issue.

After your vet gives your dog a clean bill of health, then we can address the behavioral issue.

Having a proper in-person consultation is really your best course of action. Providing a detailed history of each dog and their relationship together, as well as details about the incidents including what was going on immediately prior to the aggressive display (what room, what activity, what toys, people, etc.), how much damage was caused to each dog, was medical care necessary and if so, how many times, how the dogs were with each other after the fight, how long it took them to go back to "normal behavior" with each other, etc. A professional who is well versed in canine body language will be able to see subtle behaviors that you may miss and that couldn't be conveyed in this written forum. Seeing those subtle behaviors (looks or avoiding looks to each other, licking lips, yawning, squinting, avoidance behaviors, etc) can go a long way in helping to determine what's triggering the behavior and thus how to make it better.

One possible cause could be resource guarding - a fear-based behavior in which Gavri believes that Atlas may try to steal something Gavri holds as valuable, and so Gavri is protecting his things. This could be sleeping/resting spots, favorite toys, rooms, doorways, people, water bowl, food bowl (with or without food in it). If it's an issue of resource guarding, then we address that with management by keeping the high value items put away and only allowing Gavri to enjoy those things on his own, and by setting up formal training sessions where safety is addressed (tethered/leashed so they can't get to each other) and showing Gavri that the very best things happen when Atlas is in his presence (and that Atlas isn't stealing the prized possessions).

Jean Donaldson has a great book called Mine! A Practical Guide to Resource Guarding in Dogs . It provides a clear explanation of what resource guarding is, how it works and a step-by-step training protocol to help the dog stop doing it. The book focuses on a dog how is guarding from humans. It can be adapted to dog-dog guarding issues, but care must be taken to ensure that both dogs feel safe and are not feeling stressed. You may need to enlist the aid of a local professional trainer who is well versed in desensitization and counter conditioning and familiar with Donaldson's protocols to help you safely adapt the training program to fit your needs.

She also has a book called Fight! A Practical Guide to Dog-Dog Aggression which you may find helpful.

You can search for a professional in your area by asking for referrals from your vet or by looking on the APDT website.

You may need the assistance of a more advanced professional such as a veterinary behaviorist (a vet who has also completed a specialty in behavior). They would work with you and your regular vet to get the appropriate tests for ruling out medical issues. They will assess the dogs and provide you with a clear program for modifying the behavior. They can also prescribe and oversee any medication that might be necessary to aid the behavior modification. You can search for a vet behaviorist at
Or ask your vet if they have a vet behaviorist that they work with.

If there are none in your area, you can do a remote consultation with Cummings School of Veterinary Medicine at Tufts University.

Whenever choosing a canine professional, you should ask questions about the approach and philosophy of the person you are considering working with. The American College of Veterinary Behavior has a guideline for what to look for/avoid in a trainer.

I'm sorry I can't provide you with a specific answer, but aggression cannot be taken lightly and without much more detail and a medical history as well as a recent medical workup, it's simply not possible to provide detailed protocols. I do hope that the information I've provide leads you in the right direction to get appropriate assistance.

Good luck. Please feel free to followup if I can be of further assistance.

Los Angeles Behaviorist

Canine Behavior

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Jody Epstein, MS, CPDT-KA


IF YOU BELIEVE YOUR DOG IS ILL OR INJURED, PLEASE CONTACT YOUR LOCAL VETERINARIAN IMMEDIATELY. THIS IS NOT THE FORUM TO ADDRESS URGENT MEDICAL ISSUES. I AM NOT A LICENSED VET AND HAVE NO DIAGNOSTIC SKILLS. ***I have been answering questions on All Experts for over 8 years now. I enjoy being able to offer assistance in this forum. I do need to be clear, though. If you’re looking for free advice about a specific behavior question, you MUST submit your question to me via All Experts. If you bypass All Experts and write to me directly through my website, I will ask you to submit via All Experts. On the flip side, if you’re local to Los Angeles and you wish to speak to me privately about an in person consultation, please go through my website. I appreciate your assistance in keeping my volunteer work on the volunteer site.*** I can answer questions about the following canine behavior issues: obedience, timid/fearful & fear-based aggression, nuisance behaviors, families that are expanding with either new human or new animal members and many other issues. If you have potty training questions please first read my trio of blogs at If you still have questions after reading the blogs you can post your specific questions here. PLEASE be as specific as possible when asking a question. Give me a detailed example of the situation - dog's behavior, body language, circumstances surrounding the issue, what the consequences are (another dog's response, your response), etc. I can only provide insight if I can get a picture of the whole scenario. If I ask for further details, please provide them. In person I would normally observe for at least 90 minutes to assess the situation and the dynamics before offering tools and suggestions to modify it. In writing it is ever so much more difficult. Thank you for your participation in the process.


I have been a professional obedience trainer for 9 years, and specializing in behavior modification for 8 years. I have owned dogs my entire life. I own my own dog training and behavior modification business called Nutz About Mutz.

I am a Certified Profession Dog Trainer - Knowledge Assessed (CPDT-KA), #2133301 ; I am a member in good standing with the Association of Professional Dog Trainers (APDT), #77763 ; I am an AKC certified Canine Good Citizen evaluator (CGC), #71253

Publications ; ; Multiple articles in the local pet magazine Pet Press (found across Southern California)

I have a masters degree (MS) in Animals and Public Policy, with a minor in Animal Behavior, from Tufts Cummings School of Veterinary Medicine. I also have 3 years of graduate education in Animal Behavior and Learning from UM-Missoula and UL-Lafayette. I continue to educate myself to canine-specific behavior through extensive reading, online interactive workshops, vidoes and attending canine behavior conferences, workshops and seminars. Beginning in March, 2017, I will be the Behavior & Training Manager at Second Chance Center for Animals in Flagstaff, AZ.

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