My dog suddenly attacked my sister. What caused this aggression?

I'm sorry to hear Cooper has been acting this way. If this behavior is sudden and new, a good first step is to schedule a visit with your veterinarian. In some cases, underlying pain or illness can cause a dog to change behavior and suddenly lash out when otherwise they were sweet or friendly. Your vet can help determine if this may be the case. If Cooper checks out healthy, I then recommend talking with a trainer or veterinary behaviorist in person as aggression toward people is a very complex and serious issue which requires professional help in person. You can learn more about veterinary behaviorists and find one in your area with this link: https://www.dacvb.org/page/about

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 am very sorry to hear about Bandit. This is a scary situation if Bandit is truly giving no warning prior to his aggressive outbursts. There may be subtle changes in his behavior that are difficult to pick up on without having observed aggressive dogs in the past. Neutering may help decrease his aggression toward other dogs but truly with unpredictable aggression like this a consultation with a veterinary behaviorist is recommended. They can discuss Bandit with you in depth, examine him and observe him in different situations and come up with a training plan to help you manage him (or they may advise he not be around other dogs if they feel his behavior is too unpredictable). I would talk to Bandit's veterinarian to find out about veterinary behaviorists in your area.

Hi there. Aggression between dogs in the same household is always a complex issue, so it's difficult to provide much specific advice without being able to evaluate the dogs in person and get a detailed behavioral history. In general, small areas like doorways or staircases where the dogs get very excited and are jostling each other to get through can be common triggers for aggression - it's possible that this could be consistent with what you're describing. In that case, we usually recommend teaching the dogs to go down in a more ordered way - such as having them both stay at the top of the stairs, then calling each one down separately for a reward. In some cases, having the "problem dog" carry a toy can be helpful as it keeps them busy with something else and gives them a different outlet for their excitement. If possible, I would recommend getting in touch with a veterinary behaviorist or a good reward-based trainer who can evaluate the dogs in person and help you put together a more specific plan to work on the problem. You can search for a board-certified veterinary behaviorist here: www.dacvb.org or a qualified trainer here: www.ccpdt.org

I'm sorry to hear that you're having this problem! Aggression is a complex behavioral issue, so it's often hard to give a succinct answer in this format. It would help to have more information about what kinds of situations seem to trigger the aggression, as well as some details about how your dog acts in other contexts. In general, I can tell you that most cases of owner-directed aggression like this are related to insecurity and guarding behavior over resources - like resting places, and sometimes food bowls or chew toys. Many of these dogs will bite somewhat unpredictably when lying next to their owners on a couch or bed. If you want to try and address this behavior, I would recommend making an appointment with a veterinary behaviorist who can evaluate your dog in person and help you determine what is causing the aggression, and also give you a detailed treatment plan to work on the problem. You can search for a behaviorist in your area here: www.davcb.org In the meantime, I would recommend avoiding situations that tend to trigger the aggression as much as possible - this may mean blocking Sam's access to the couch, bed, or other areas where he has tried to bite you. Punishment of any kind for this behavior is not recommended, as it tends to make the dog more defensive and worsen the aggression over time. Instead, if he growls or tries to bite, calmly walk away or call him to you for a treat to help diffuse the situation.

I'm sorry to hear that you're having this problem with Runt! Aggression towards housemate dogs is a complex behavioral issue that can have a variety of different underlying causes, so it's hard to give any specific advice without being able to evalaute the dogs in person and get a much more detailed behavior history. Because of this, I would strongly recommend getting in touch with a veterinary behaviorist who can do a full assessment of the situation and help you put together a detailed plan to address the aggression. You can search for one in your area here: www.dacvb.org In the meantime, the best advice I can give is to keep the attacking dog separated from the other dogs in your household until you are able to get a behaviorist in to help. This will help keep the problem from escalating, and keep any of the dogs from being injured in the meantime.

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.