Q: I adopted an adorable medium-sized Terrier mix about a month ago. He is about 2 years old and appears to be sweet, gentle and relatively submissive. He has not yet been neutered. He became very ill shortly after I brought him home. He either had distemper or a very sever upper respiratory infection. We do not know his background. He was picked up by Animal Control in a residential neighborhood. He appears to me to have been somebody's much loved pet, but who knows.

Part of the way through his illness, he appeared to adopt a wariness that evidenced itself at the vet. At home, when he was on codeine cough medicine--may or may not be relevant--he snapped at 1 of my sons who came up behind him and reached to pet him. He also growled at another of my sons who woke him up--also surprising him. The wariness faded as he came off the cough medicine and became sicker. Around my family, he could not be more gentle, loving, and submissive. Since he has gotten well--about a week now--he appears more territorial. He barks at sounds and people at the door. Sometimes the bark is preceded by a growl. I can't tell if it is a threat or not. I don't think so, but am not sure.

When I walk him on a lead by himself, he does not usually bark at people or dogs. When I have walked him with my female Golden and other family members, he growled and then barked at little girls who approached us, and barked at a neighbor. He also barks at people who come to the house, until I have talked to the person for a while. He clearly takes his cues from me.

I have also noticed that he seems worried when we are out of our neighborhood--our normal walk route--and sees people. He does not bark or growl but he does not wag his tail and approach them. If they take it slowly and let them approach, he slowly warms up. Does this sound like a significant and potentially dangerous problem? Will time and working with him take care of this and what should I do in the meantime? Would obedience classes be a good idea or should I wait until he is more settled with us? He is quite confident and comfortable with me and my family now.

A: He really is new with you and has been ill. At this point, I don't think anyone could be sure of his temperament. You should listen to your doubts, though. He sounds like a dog who could function fine in an obedience class, so I would go ahead and enroll in classes at a local obedience club. The clubs are listed by state on the AKC website at http://www.akc.org.

Class will give you a much better idea of his reactions and also give you a broader "vocabulary" for communicating with him. Clicker training would be fine too, if that interests you. Practice your training exercises on your walks as much as possible. This will also help transfer the communication and his sense of you as a competent leader to those situations.

For the house, I would do everything you can to help him enjoy visitors. Perhaps a cookie jar at the door for them to give him a treat when he is nicely sitting and not jumping on them. Don't give a treat after barking. Try to catch him before he starts barking and give a treat to divert his mind from the need to bark.

Do go ahead with the neuter as soon as your vet is satisfied he's healthy enough because that will relieve the dog of pressures he certainly doesn't need. Some dogs are naturally reserved, which is fine as long as it doesn't mask or turn into aggression. Nothing you have mentioned sounds sinister, except you are there and I'm not and you are sensing something that worries you. So listen to your doubts, proceed with neutering and training class, and enlist the aid of a trainer or behavior specialist at any time you aren't sure things are going the right direction.