Is my Chihuahua puppy's fear of strangers normal? How to help him?

Hi there! Thanks for using Petco Pet Education Center, formerly Petcoach! He is right at the perfect socialization stage right now and for the next few months to come. He can get used to bigger dogs if introduced to him slowly and if you remain persistent. It has to be in a controlled environment meaning that you bring the larger dog to him slowly. At least try to start with a dog who is not very active and that is for sure nice. He can definitely get used to large dogs. The main thing is associating that experience with something positive by for example giving him treats and praise. Consistency and persistence are key. Good luck with your pup!

It would be best to consult a dog behaviorist, this isn't an issue that can be easily solved, especially as Chihuahuas in general tend to do that a lot but with the right professional guiding you in person it is possible.

Trust can take a long time to build. Some dogs who may have had fearful experiences will remember these and it make take a while to over come. Men do tend to be more intimidating due to a larger stature and deeper voice . It's also important to not tower over Sandy. Squat down to get on her level. Try to find a toy she really likes and have play sessions with her. Also make sure you are the one who cares for her (feeding, walks, playing). In general, this will form a positive association and can help to bond her with you. Also, try not to force her into hanging out with you. Make sure to heavily reward any behavior that appears to be what you want (like approaching you on her own). Make sure to use a higher pitched voice for positive association until she is comfortable. Be patient and positive.

Any abrupt behavioral change is a good excuse to get him in to see your vet. He may be starting to develop a medical condition that should be investigated but it's so early that the only symptom he is displaying is this strange behavior. There may be something happening periodically that is making him uncomfortable of the feeling comes and goes, but either way, it should be looked into by your vet. Your vet will do a thorough exam, possibly some x-rays and/or bloodwork, as indicated. Based on these results your vet will have a better idea what is going on and be better able to advise you as to what action should be taken.

Chihuahuas are, by nature, noisy little guys. It's likely that they evolved to become excessive barkers because their small size makes barking one of the few ways they can gain attention. For more facts and characteristics about Chihuahuas, visit PetCoach's breed page: www.petcoach.co/breed/chihuahua

There are a couple things you can do that may help smooth the introduction. Give the adult Chihuahua a lot of exercise prior to meeting the puppy so that she is physically tired. Have a barrier such as a baby gate in place so that she can smell the puppy but not cause injury. Make sure the puppy does not jump on her or otherwise cause her stress. You are correct that you need to always make sure the puppy is protected as the adult dog may hurt it. You should also keep in mind that not all dogs like other dogs. Some of them prefer to live in single dog households and that is simply their personality. Make sure to correct any bad behavior from the adult dog. Correct the puppy to but this will be a little bit different because it is still learning. Best of luck and please feel free to post any additional questions. And yes, this is a free service! We do have private consultations available for a fee.

Aggression and fear are complicated. Some dogs can make some progress with appropriate guidance and consistency. For such guidance you will need to work with a trainer or a behaviorist. They must show you how to read his body language and how to respond in a fashion to modify their behavior. Certainly you can read many books about training and canine behavior as it is all helpful but likely you will still need professional assistance. Best of luck and please feel free to post any additional questions.