Consequences of owning a 'guard' dog

American satirist Peter De Vries once said, "There are times when parenthood seems nothing more than feeding the hand that bites you." With owners of aggressive dogs, the witticism hardly elicits a chuckle.

There are many types of canine aggression: food aggression, territorial aggression, fear-based aggression, dominant aggression, protection aggression, predatory aggression, punishment aggression, pain-based aggression. Pinpointing the source of a dog's aggression is instrumental to developing a safe and effective training regime. But it's equally important to have realistic expectations about what it means to own an aggressive dog.

Take the following letter from a reader:

"My 5-year-old German shepherd is fine with my two roommates and me. We could take him by his back legs and drag him around the house if the mood were to strike us. I can remove bones from his mouth and put my hand in his food dish. He comes, leaves it and sits on command. If I tell him to stay, he will literally stay there for hours until I tell him to come here. I thought bringing him to college as my guard dog was a good idea, but it turns out he is too good at his job.

"If friends come over, one second they will be petting him, the next they will be trying to fend him off. As soon as I call him off, he leaves, but he has successfully bitten eight people, broken skin three times, attacked countless times and ripped one shirt when he lunged onto a friend's chest. I don't understand what kind of aggression this is. Everyone thinks he is a beautiful dog, and he really is! I just can't believe my peaceful giant has earned the nicknames among our friends (and the guys who do work around our house) as "Cujo" and "devil dog." Please help me!"

Setting Cujo loose in a room full of friends is a good way to make enemies. There are consequences to owning an aggressive dog — physical, psychological and legal consequences. This is why it's imperative that the owners of these dogs keep their expectations firmly grounded.

If your dog has bitten, expect that he'll bite again, particularly if he has not received any training to curb the problem behavior.

If your dog has shown signs of aggression — growling, snarling, biting, snapping — expect that the possibility of aggression is always there, even if he has been professionally trained. Aggression can't be cured, but it can be curbed.