My son bought a dapple daschund from the mall pet shop and the dog is now about 6 months old. Normally very playful and fun until it comes to food. If the dog is eating and is disturbed in any way he starts growling, barking and has shown his teeth and made menacing advances and/or bitten someone. Is this common to the breed? I certainly hope not as he was very expensive and my son does not want to give him up. If it's not in the breed then what can we do to stop this behavior? We're concerned that we might have a guest in the house, particularly a child at some point and are setting ourselves up for a lawsuit. Please help!

RubyPitbull

What your dog is doing is called "guarding behavior". Anything that he considers his, will create an aggressive reaction if he thinks someone will try to take it away. Although poor breeding practices can create a heightened aggressiveness in some dogs, your problem is in all probability a training one.

Dogs view the world in a different way than we do. Everything is geared toward a pack structure in which there is one male alpha and one female alpha. The others in the pack follow their leader. Usually after bringing a puppy into the household, the first thing I recommend is to handle his food while he is eating and his toys while he is playing. Stick your hand in the food bowl grabbing at the food, dropping it back in after a few moments, and pet him while he is eating. If you are concerned about a small child being bitten you go a bit farther when the dog is either eating or playing with a toy, by very gently but consistently tugging on his ears and tail, taking the toy away for a few minutes, then returning it to the dog. This ensures that if a small child bothers the dog for any reason, he will ignore it and not snap, patiently wait to get his toy back, or simply walk away. Since your little guy is now 6 months old, your son has to undo the training that allowed his dog to think he is the leader of the pack. I don't recommend he try the usual techniques now or he will get bitten. Here is a link that both labman and I use that has some very concise and solid steps to ensure your dog knows who is the alpha dog in the household. Everyone in the home needs to follow these steps to ensure that the dog knows who is boss. Try it for a few weeks, and see how is goes. If you are having problems, post back and explain in detail what is occuring. Establishing and Keeping Alpha Position, Letting your dog know you are the boss
Once the dog is consistently responding properly and recognizes that he is at the bottom of the ladder in the chain of command (you see the current aggressive behavior stop), I suggest your son start working on the technique with the food & toys that I outlined above.