Our 4-year old sheltie-fox terrier mix is terrified of other dogs, showing her teeth and hiding under tables. She was raised with a lab who she adores, and she is great with all people, even strangers. But when we visit other dogs, or other dogs come to visit, she clings to me and doesn't let other dogs approach. When they do, she growls and shows her teeth. She has never been hurt by another dog to my knowledge.

How do you react when you're about to meet another dog with your sheltie? Our body language is what dogs read and understand. It's natural (because you've had bad experiences with her before) that you will tense up when another dog approaches. Your dog senses this and acts accordingly.

It's time to retrain her, and yes, it can be done. This is most likely a learned response, and she has to unlearn it. I recommend Cesar Milans "be the pack leader" book, there are some helpful hints on how to change your body language and assert yourself as leader.

Good luck.