Dear Cesar:

Our Shih-Tzu Diva is loving, playful, and my 6-year-old's best friend. The problem is, when friends or relatives come to the door, Diva goes bananas. She jumps up and down, lunges at the door, and won't stop barking. When the guests finally make it inside, she never bites them, but growls and watches them with her lip twitching. It has become so bad that we have to lock her in my daughter's bedroom every time someone comes over. When we do, she'll howl for a time, then just lay down, and get depressed.

What can we do to stop her from being aggressive towards strangers?

Deborah H.

Dear Deborah,

Diva believes she is the protector of your household. She may be protective of -- or possessive of -- your small daughter. This is natural behavior for a dog that is a pack leader; however, when dogs live with humans, the humans must always be the pack leaders. What I can't tell from your letter is how you reacted when Diva started her behavior. Chances are, you coddled her, talked soothingly to her, tried to let her know it was "OK." If Diva were human, that reaction might make sense. But Diva is a dog. By trying to soothe her tantrums, you are actually encouraging and nurturing that behavior.

What concerns me most about your letter is the growling and twitching you describe. This is a warning sign that could possibly lead to a bite. In this case, you must immediately find a qualified professional to work with you and make certain Diva's aggression doesn't get any more out of control. Ultimately, when company comes to the door, Diva should recognize that you are her pack leader, and that when you tell her to stop a behavior, she should stop it right away. It will take time and patience, but you must learn to take the leadership role in your own home before Diva will become the hospitable companion you desire.

Stay calm and assertive,

Cesar Millan