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Canine Behavior/Dog attacking puppy


I have a 5 year old male American Bulldog. He has always been socialized and we have never had an issue with him or introducing him to new pets. We got a new puppy a year ago and he loved her. Sadly, that dog is no longer with us, and this week we got a new puppy. The puppy is a 10 week old female of the same breed. The first night we had her, my male snapped at her, cutting her eye and requiring a trip to the ER. That incident he was trying to turn around and bumped into her. Two days later he attacked her. Cutting her jaw pretty bad and leaving a few punctures, prompting another expensive ER visit. This incident occurred when he was chewing on a toy and the puppy tried to take it. He will also growl at the puppy whenever she comes around. I've never seen this behavior before, and this isn't our first puppy, so I am at a loss as to how to handle this.

Thank you for your question. My concern here is that your older dog has caused damage ssevere enough to require immediate medical attention. Twice.

The first time may have been incidental contact as you suggested. The second time may have been just teaching a puppy to mind her manners and respect his space (albeit with a greater intensity than is necessary), or it could have been resource guarding. The latter is a fear-based behavior and all social animals will display at times. Essentially it is when the individual feels that some item is valuable enough that it's worth protecting and fighting for. That item may be a toy, food, sleeping spot, water, room, doorway, a person... I've even seen dogs guard fallen leaves or sticks on the ground.

Without a more indepth discussion, I can't know what motivated your dog's behavior, though my knee-jerk reaction is resource guarding. And that may have played a role in the first incident as well even if you didn't recognize a trigger.

Resource guarding is actually a fairly easy behavior issue to treat. However, because there have already been two incidents with injuries, I STRONGLY encourage you to seek out proessional help rather than trying to fix this on your own. Because there are two dogs involved, we must make sure that BOTH dogs feel safe and are not stressed and so it's a bit more of a challenge than a dog who is guarding from a human.

In the meantime, management is key. Your puppy is in the middle of her socialization period. Each time the older dog lashes out at her, she's learning that big dogs are scary and not trustworthy and this will effect her behavior toward other dogs as she gets older. Therefore, it's imperative that we protect her from the older dog. This means that the puppy is not in the same space with the older dog outside of formal training set-ups with the guidance of a professional in person. And when they are in the same space, the older dog (at least until improveent occurs) should be in a basket muzzle. This allows for safety as well as the ability to provide food reward to the older dog for good behavior.

Here is an excellent video that teaches you how to teach your dog to love his muzzle.

As for the trainer you work with, I encourage you to interview any potential trainer.

Key words/equipment that you WANT to hear include: positive reinforcement, force free, desensitization, counter conditioning, reward based training, body harness, face collar, clicker; protocols include: Look At That, Behavior Adjustment Training, Click to Calm.

Giants of the industry for referene include: Jean Donaldson, Patricia McConnell, Grisha Stewart, Ian Dunbar, Pat Miller, Sophia Yin

Key words/equipment that you DO NOT want to hear include: balanced training, correction training, choke chain/check collar, prong/pinch collar, electronic/shock/vibration collar; techniques to avoid: yank/jerk/pop the leash, 'alpha roll', finger jabs to the neck, foot/toe to the ribs or kidneys, stringing up/hanging dog by collar/leash, helicoptering the dog (exactly what it sounds like).

Your vet may know a local professional tha they can refer to you. Or you may search for a trainer at the APDT website (association of Professional Dog Trainers):

I'm sorry I can't be more specific help in this circumstnace. I wish you the best of 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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