What has prompted this? You say the dog is 8. Is this new behavior? Has the dog always had a problem with aggression?

The dog has always been leery about meeting strangers, so it isn't something new.....

I suggest asking your vet for an animal behaviorist recommendation. They help owners understand and work with their pets to resolve behavior issues. Behavior consultants help animals in a very holistic way, taking into account the environment within which they live and learn, the people and other animals they interact.

If your vet doesn't have a suggestion, you can Google for those in your area.

Has the dog had any formal training at all? Does he know any commands? Or is he just the family pet that runs the show by himself? Any dog needs initial training, to learn his place in the pecking order and to know who is the "leader" of the pack. If no one has done this, the dog fills the void himself and that is not a good thing. And unless everyone in the family is on board with training, having someone else "train" the dog will not really solve the problem. It's a commitment to be sure, but dogs that are trained are a lot nicer to live with. Good luck.

A dog that shows aggression to people usually exhibits some part of the following sequence of increasingly intense behaviors:

• Showing teeth
• Snarl (a combination of growling and showing teeth)
• Snap
• Quick nip that leaves no mark
• Quick bite that tears the skin
• Bite with enough pressure to cause a bruise
• Bite that causes puncture wounds
• Repeated bites in rapid succession
• Bite and shake

Dogs don’t always follow this sequence, and they often do several of the behaviors above simultaneously. Many times, pet parents don’t recognize the warning signs before a bite, so they perceive their dogs as suddenly flying off the handle. However, that’s rarely the case. It can be just milliseconds between a warning and a bite, but dogs rarely bite without giving some type of warning beforehand.

Which is all the more reason(s) to seek professional help. And avoid a huge lawsuit.

Or put the dog somewhere safe, where kids/strangers can't get to him, when your kids have friends over.

I would get his thyroid tested to be sure that isn't causing increased aggression. Even a low normal can affect dogs.

I take it he doesn't do this with you? Is your husband a loud talker? etc that may be unnerving the dog? as a german shepherd mix it is likely in his nature to be protective, that's one of the reasons they make good guard dogs and don't get all goofy with strangers. But it sounds like he needs some desensitization to strangers involving meeting more strangers in a non threatening way until he gets more comfortable about it. The problem is, how comfortable does your son want him to be with strangers? esp if he partly got him to be a good guard dog.

If it's just about getting him to accept your husband, then he needs to see interacting with your husband as a positive thing. something as simple as getting your husband to feed him can generate a lot of good will

Have you thought about finding a professional trainer?? Dog aggression is no laughing matter. You need to get it under control ASAP before the problem becomes even worse and there's nothing you can do about it.

Have you had the dog since it was a puppy? Has it always behaved this way?

Sounds like he wasn't properly socialized during his training. Try professional training. A dog should be well socialized; in my experiences, my pets have all been well-trained and extremely socialized but they protected my family and home when needed.