Dog instincts

Dogs in general have instinctive behaviors that are seen depending on the breed you have. Pointers actually "point" with out anyone having to teach the dog how to do this. Other dogs like herding dogs for example, are naturally able to herd a flock and they tend to this with humans too, especially with children.

Dogs that defend their owners: One of the great things about dogs is that to them their owner is the boss; therefore whatever the owner says is what goes. If a dogs sees that his owner is talking in a friendly way with someone, the dog will remain calm, however if it were the other way around, the dog's behavior would be come aggressive because the dog always sides for his owner. The same thing applies to the territory in which a dog lives in, which he will defend at all times from strangers. To avoid a dog from attacking a guest, it's best to present the dog to people that go inside the house for the first time and especially to people who come near or in the house whenever the owner is not around such as the mail man, cleaning person etc.

Dog aggression: While a certain amount of aggression in dogs is perfectly normal and a natural instinctive part of their psychological make up, too much aggression is not only a bad sign but also potentially dangerous.
There are two main reasons for aggression, one being aggressiveness as a result of fear and the other aggressiveness brought on by the dog's desire to dominate. It is important to help your puppy overcome its aggressiveness brought on by fear. One good way to do this is to always keep full control over any situations where your puppy is interacting with people or animals. A puppy that is well socialized will grow up with less fear of new things, animals or people. If your puppy shows fear towards anything in particular you can further help it by holding it in your arms and then slowly approaching the thing that is causing your puppy fear. Calmly talk with your puppy and while keeping it close to your chest demonstrate that the object causing fear really isn't something to be afraid of at all. Praise your dog for not acting aggressively toward the object. Aggression brought on by a desire to dominate should be dealt with while the dog is still a puppy also. The way to help your dog overcome this problem is to make sure that it understands that within the household hierarchy it is at the bottom of the totem pole. The dog must understand that all the human family members hold a higher rank than it does and that the humans are the dominant ones.