The best defense

One thing that most dog owners hope is that their pets will offer them protection. I am excluding all dogs that are not house pets (Eg. Police dog, Military police dogs). I am also excluding dogs that are specially trained to attack people.

The sad fact is that "protection" is sort of iffy. Do I believe that there are dogs that have undergone obedience training (excluding the aggressive curriculum) that will protect their owners? Of course, I do. I have seen footage of dogs attacking wildlife intruding or even attacking their owners. However, most people hope that the dogs will also protect their property. At this point, I have bad news for most dog owners. Most dogs would not be able to protect their owners' property without training. 

Most owners will argue that their dogs often bark at strangers or even rush to the boundary of the property to bark at the stranger. This does not signify anything. My neighbour has a dog that will act aggressively towards me in the day but behave indifferently towards me in the night. To deter intruders, the dog must approach the stranger aggressively and bite the intruder. 

Most dogs will approach the intruder. Some dogs will even give a nip at the intruder or growl at the intruder. I need to be fair to the dogs as well. Dogs that are too aggressive either get neutered or put down. This prevents the aggressive genes from entering the gene pool. Although there are a few people that train dogs for dog fighting and protection, these people are not numerous enough to tip the balance. Most people get their dogs from puppy mills or more reputable breeders. Either way, these places seldom breed dogs for aggressive behaviour. Otherwise, I have no idea what the owners of pugs or chihuahua are expecting (Aggressive ankle biters?).

Even if the dog is ready to be aggressive towards intruders, it also needs to be trained not to eat food that is offered by strangers. The fact that postal workers in the US are carrying treats for dogs suggest that most aggressive dogs can be bribed. The fact is that most dog owners do not want their dogs to attack other people indiscriminately. 

So the dumb animal has to learn that there are certain people it should not attack (Eg. Neighbours, relatives and postal workers). The dumb animal also has to learn that certain occasions, it should also avoid attacking people (Eg. Guests at parties). Can you blame the dog if it decides that not biting is the best solution?