My 4-year-old male dog is suddenly aggressive. What should I do?

There are many possible reasons for this, I'm afraid - aggression is a complex behavior issue, so it can be hard to provide a succinct answer in this format. Many dogs develop aggression issues related to fear or anxiety around the age of 2-3 when they reach social maturity, so it's possible that this may be the issue. Or, since I see that Chucky is a bit older than that, he may have a medical problem causing him to be painful or uncomfortable - this is a common reason for "new" aggression in a previously friendly dog. I would recommend having Chucky examined by a vet as a good first step - he/she can check for anything that may be causing him pain or making him not feel well, and get him started on treatment if needed. If everything is normal medically, then it would be best to make an appointment with a veterinary behaviorist to help you determine what is causing the aggression - he/she can observe your dogs in person and also give you a step-by-step treatment plan to work on the issue.

Oh dear! That is a worry for sure! It's really important that you don't get hurt, because dog bites can be pretty serious. I would suggest making an appointment with your vet to talk about possibilities. They might be able to link you up with a behaviorist, or dog trainer that could help a lot. There also could be medications that might help. Or, like you said, there could be a medical problem that is upsetting him.

I'm sorry to hear that you're having this problem! If this has been a fairly sudden behavior change for Elsa, the first thing I would suggest would be to have her examined by a vet to see if there may be a medial reason for the aggression - many illnesses including thyroid problems and neurologic issues can cause sudden mood swings and behavior changes like this, as well as anything that may be painful such as an injury of some kind, arthritis, etc. If your vet determines that Elsa is healthy, then I would strongly recommend making an appointment with a veterinary behaviorist as the next step. Aggression towards humans is a serious and complex behavior issue that needs to be handled by a professional who can work with your dog in person. The behaviorist will evaluate your dog and help you determine what is triggering the aggression, then put together a detailed training plan to work on the problem. You can search for a board-certified veterinary behaviorist in your area here: www.dacvb.org

I certainly sympathize with your situation. Since Digby is 7 years old and this is a new behavior, I would start by having your veterinarian examine Digby to make sure there isn't a medical condition that is contributing to the change in his behavior. Your veterinarian may recommend trying medication depending on Digby's situation and behavior. If everything is normal on examination, ask your veterinarian for a recommendation for a behaviorist or trainer. You will need to commit to a training regimen to change Digby's behavior when he sees another dog. This can be a long process, but will be worth it. Good luck! Thanks for using Petco Pet Education Center, formerly Petcoach.

Before assuming this is a behavior issue, I would want to rule out a possible medical issue first. When I hear about sudden changes resulting in aggressiveness, the possibility of pain or discomfort in one of the dogs could be the root of the problem. When a dog is not feeling well, it is only natural for it to react in a negative way if one of its buddies is trying to get it to act normally. A thorough physical exam should be performed by a veterinarian in order to rule out any sort of orthopedic or neurologic pain. Thyroid conditions can also be responsible for behavior changes as well. If it turns out that no medical issue can be be identified, you will have to start considering what may have started this sudden change of heart by Mill. You will have to think back to when it started, when the problem occurs most, where it occurs most, who is around when it is occurring, who ISN'T around when it is occurring, so on and so forth. These types of issues can be long and complicated to resolve, but usually as soon as the issue is identified the road forward becomes much easier.

Thank you for submitting your question regarding Benny. I am sorry to hear about his behavior changes. That is very upsetting. I recommend that he sees his veterinarian. My first thought is that he could have a medical problem contributing to the change you are observing in him. For example, if a dog is painful from arthritis, an ear infection, periodontal disease or some other issue, he may act out aggressively. Another consideration is if he has dementia. This is common in older pets and is frequently observed at night. The veterinarian will thoroughly examine him and determine how best to help you both. In the meantime, be careful around him to keep yourself safe and do not give any over-the-counter pain medications as these can be toxic to dogs. I hope this information helps!

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Bruno. When a puppy shows aggression, I immediately advise neutering him to remove the male hormone-driven behaviors. I would advise taking him to your veterinarian for their opinion also. He may have some medical reason for his sudden onset of aggression. Your vet can gather a history, perform an exam and then offer a diagnostic/treatment plan based on their findings. Possible tests include fecal/blood/urine tests and x-rays to look for underlying medical problems that could cause aggression. If a behavioral problem is suspected, then neutering, behavior modification, and drug therapy can be tried. I wish you good luck with Bruno