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Canine Behavior/agression in my 10 year old american bulldog


My 10 year old American Bulldog has been becoming increasingly over assertive and nearly aggressive. He has always been somewhat assertive and has needed reminders over the years that he is not "in charge". He was very well socialized from 6 months of age. We always took him everywhere with us and let him experience all kinds of situations early on. However, due to our own personal health issues, he hasn't had continued socialization beyond age 4. Since then, he has mostly been at home with those he knows and regular rides in the car. His personality has always been sweet to the people he knows and very devoted and protective of his family, and surprisingly shows motherly instincts to all small creatures. He is very large,trim, and muscular. Recently, he is slower to respond to commands like "sit" and "no". We aren't sure if this is due to hearing, cognition, or if arthritis is playing a role here. We don't seen any other physical signs of arthritis. A few times recently, he has growled in response to being corrected. We have 2 other dogs that he has always been good to, a 5 year old female American Bulldog, and a 1 year old male Newfoundland. Our older dog has always been a wonderful part of our family and it is sad for us to see these changes in him. Is this part of aging? We are concerned that he may bite us or one of our other dogs. We have been very careful to not bring anyone he doesn't know into our home, for their and his protection. This has created some issues with our 13 year old having friend over. Can these problems be corrected? What do you think the cause may be? We adore our dog but obviously can't put others at risk. Please advise. Thank you.

I don't know what you mean by "correction"....this is never a "good" thing.  Best approach is to reward behavior you want, ignore behavior your don't want (by turning your back, leaving the room, or redirecting to trained behavior you can reward).  

In a multiple dog household, "rank" (placement in social hierarchy) is dependent on a variety of things.  These include the temperament and age of each individual dog as well as human interaction and any "promotion" done (inadvertently) by humans among/between other dog(s).  

Your statement regarding the safety of this dog and your concerns because of your young teen, coupled with the stated fact that this is all fairly recent behavior, makes me lean toward a full physical and behavioral evaluation by a veterinary behaviorist, first.

Let's find one ASAP.  This can be done in three ways: contact the veterinary college in your geographical area (they definitely have one on staff and may know of others); or from the following sites:

In Berkeley, CA, there is an extremely well known veterinary behaviorist who most likely knows anyone on the west coast or its immediate vicinity.  His name is Dr. Ian Dunbar and his contact information is:

This may very well be caused by a combination of physical problems and aging (loss of status in a dog pack due to visible - to other dogs - infirmity) so to offer a behavior modification program is not a responsible choice for me, since I cannot see anything from here.  Start with the veterinary behaviorist.  Report back using followup feature once you have any diagnosis or opinion.  I will most likely refer you to a certified applied animal behaviorist.  Aggression is nothing to mess with from a distance.

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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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