My dog is friendly but suddenly bites. What's causing this change?

I would recommend having a trainer come to your home and working with Chai. I would have them walk with you and Chai to see exactly what is going on and then work with you and her to help you control/fix the problem. I don't like the fact that she became aggressive towards the lady and so I would call someone as soon as possible. Your veterinarian should know someone who should e able to help you. If this is a new behavior I would recommend having your veterinarian do a full evaluation of Chai just to make sure there isn't anything medical going on with her. Thank you for using Petco Pet Education Center, formerly Petcoach.

Abrupt changes in behavior like this in dogs is very concerning to me. I would be worried about some underlying neurologic disorder that could be going on. If nothing has changed at home, her routine, or the environment in general, then I would suspect an underlying medical issue. I would recommend taking her to be examined by your veterinarian and possibly having some lab work performed so they can try and determine what is going on. Your vet may recommend further work up by veterinary neurologist or may recommend a behavior modification drugs like Xanax or Prozac. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck.

I highly recommend consulting with a trainer. A trainer will be able to walk with you and see what is going on. Was it how Angel was approach? Was she being protective? did she not like something? There are a lot of unanswered questions that we may never know during this situation but with a trainer then can recreate the situation and help work with you and both dogs to make sure it doesn't happen again. Thank you for using Petco Pet Education Center, formerly Petcoach.

Thanks for using Petco Pet Education Center, formerly Petcoach! This can indeed be fixed. However, this does require training in person with a qualified dog trainer. I would recommend you contact a dog trainer that can work with you in person. Best of luck!

I would have a trainer come to your home to see exactly what is going on. It may be the way you approach her or it could be something else triggering this. They then can work with you to tell you how to fix it and deal with these situations. Your veterinarian or people in your neighborhood would be the best people to ask who is a good trainer that comes to the house. Thank you for using Petco Pet Education Center, formerly Petcoach.

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach. I am sorry to hear that this has happened. This behavior is certainly concerning as you don't want Boston to cause serious harm to your wife or anyone else for that matter. I would recommend taking Boston to a behaviorist for training and other recommendations. There are trainers that will take Boston for several weeks for the training or trainers that will come to your house for in home training. At 4 months of age, this is easier to correct than when he is 4 years old. Now is the time to take action as it is much easier to train a puppy. I hope this helps and for now, please take the necessary precautions and keep Boston away from anyone until he is appropriately trained.

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.