When someone comes to the house and your dog comes out to investigate, and then sees that person turn and go away, the dog thinks he has chased the "intruder" off his territory. As the dog experiences someone coming. then leaving after the dog has come out, the dog's confidence builds and so does his territorial behavior. (That is the same way dogs are taught attack work, the helper approaches the dog and then turns and runs when the dog comes forward. The dog thinks he chased the person away, and repeat experiences build his confidence in his own aggression. The answer to unwanted aggression lies in your becoming the authority (alpha wolf) that the dog must respect and submit to. People and dogs relate much as the members of a wolf pack relate. The alpha wolf or alpha pair do not allow the subordinates to do anything without the alpha wolfs permission. If a subordinate takes the initiative to do something that challenges the authority of the alpha, the alpha quickly demands submission from the subordinate. The book "The Art of Raising A Puppy" by the monks of New Skete is one of the best books I've seen on how to communicate with your dog in a way he understands, using methods to be alpha and gain your dog's respect, then gaining further control of your dog through obedience training. All dogs should have basic obedience training. Obedience training puts you in control of the dog, and comes in very handy. In fact, once you own a dog that's learned to obey basic obedience commands well, you will never again want to have an untrained dog. Training also puts YOU in charge, right now your dog is in charge, making the decisions when to defend the territory instead of letting you be the one to make the decisions. You need to leash your dog when someone comes and goes, such as the mailman. Briefly you can teach your dog by letting your dog bark a couple of times to announce someone's arrival, then say "Enough" or similar command. At that point the dog should learn to stop barking and go sit beside you, waiting for you to tell him what to do next. (Even in Schutzhund and police work, handlers are supposed to train the dogs well enough on CONTROL exercises as well as the more impressive looking aggression exercises. Schutzhund rules now require a dog to let go of the handler's sleeve when the trainer commands the dog to OUT.) Places to do obedience training are easy to find in most areas. PetSmart and other petshop chains often run basic obedience classes, local dog clubs often run basic obedience classes, and private individuals often also run basic obedience classes. Working in a class supervised by the teacher (who should be an experienced trainer and knowledgeable about training dogs of different breeds with different levels of intellect, independence or dependence, personalities and trainability) helps a lot when you haven't learned to train and are dealing with a dog with problems. The teacher should be able to give you pointers on ways to solve your problem. You can also check with your vet to find out if there is any animal behaviorist in your area to help you. Go to area dog shows and try to meet people who breed and work with your breed. When not getting ready for the ring or actually showing, handlers, breeders, and trainers at dog shows are usually very friendly and very willing to be helpful. Even the top dog handlers are usually willing to help a novice person, as long as that person asks for the help when the handler isn't busy trying to get dogs ready and shown. The sooner you start taking steps to gain control of your dog, gain his respect, and establish yourself as in charge of your home and yard (YOUR TERRITORY with YOU IN CHARGE OF IT, instead of your dog being in charge and making his own decisions), the quicker and easier it will likely be to solve the problem. The longer the problem goes without being confronted and solved in a positive way, the worse the problem will become. You didn't say the age of your dog, but I would guess that he's an adolescent, just beginning to mature and start feeling like a teenage boy does when he starts maturing and wants to find ways to show people he's no longer a child but becoming "macho". Adolescence is the time in a dog's life when you usually see the worst behaviors that dogs have to offer, unless the dog gets away with the behavior instead of learning that he's not the boss of the house. Adolescent dogs are just like teenage children, testing your authority and testing the rules to see what they can get away with.

The bottom line is that YOU are responsible for your dog having access to anyone on your property...inside your house (excepting for someone breaking in! and then I say all bets are off...SIC em big boy! Good dog!), or outside in your yard. Your dog, unless he was secured to a line or in a fenced in space should not have access to the casual passer by. If your gate is not kept locked and you are allowing people on your property, it is likely that the local law in your area prohibits your dog, (of any breed or size) from being able to access those people! (and you don't necessarily want to post a sign about your dog...in some places that constitutes prior knowledge that you KNEW your dog would likely bite and did not take steps to insure it could not bite...this differs to some degree from location to location...speak to your home owner's insurance agent, for the legal scoop for YOUR area!) I wouldn't assume this fellow was being aggressive with this encounter at all. He may be a young, inexperienced dog...12 to 24 months, he could be entering puberty! Which can cause hormonal surges in animals the same as humans! He may not have been "biting" the sleeve, but trying to grab at it...even to play...I would have to see what his total attitude was, to better assist you. If you are fearful, I would suggest you contact your local humane group or your Vet and ask for suggestions as to where you can take him to have him temperament tested. (By a professional!) This will show if there is any true cause for concern, or if it is simply a matter of refining your training, perhaps with the help of a professional trainer who uses Positive Reinforcement training. As I mentioned... the book suggested, Monks of New Skeet, promote AVERSION training and it's ok in some situations...IF YOU KNOW WHAT YOU ARE DOING, but it is not considered to be the optimum training method by very many professionals, or Behaviorist in today's world...+R is simply better...it forms a stronger, more accountable relationship between the human and the animal...dog, horse, tiger, elephant...it helps the dog to UNDERSTAND within their mental ability and range, what the REWARD IS to be gained for doing a trained behavior correctly. It also supports the animal in learning the behavior and in "choosing" to do the behavior more consistently once the lesson is fully learned. Especially if you are working or allowing your dog to be "at liberty," that is OFF a lead, you WANT the animal to have trust and motivation to follow through with doing the trained behavior when asked to do it. Training with Negative methods (abusive, or "show him whose boss" mentality MAY well cause your dog to DO the behavior...out of fear of what might happen if he doesn't do it) This can happen with Aversion training as well. Where as, overwhelmingly, with +R the animal does the learned behavior when asked, because the lesson included a clear and desired REWARD for doing it. The rate of success and willingness goes way up with +R...and bottom line is we want the animal to do what we are asking that it knows HOW to do, and when we ask we want it NOW. This is critical if your dog is about to chase a cat into the street and you see a car coming down the street...the desire to chase the cat is enough of a distraction to have to counter and override! I sure as heck don't want the dog to even consider that I might PUNISH HIM...I want him to STOP NOW, turn around and return to ME...ANTICIPATING a great reward for doing it!!! Basic commands to train for your specific worry here would include...the usual..Sit, Stay, Lay down, Come...and also...LEAVE IT, DROP IT and I train my own dogs and my students dog's the command "HO!" TO STOP, you can use any word you want, the action is that the dog should freeze and not move. Some drop into a sit, some even drop into the lay down position, I don't personally care as long as the dog stops moving forward at the command! I hope this helps some with understanding the training methods...and the types of commands that would help. You can always email me for more specifics...or seek someone who uses +R (the ASPCA can help you there too!) that you feel comfortable with. These are Grand Dogs and generally easy going in nature, I would not expect one to be truly aggressive, protective yes, out to nail someone, no.

First of all, your dog shouldn't have access to anyone! Google "doggie boot camp". You do these things yourself and it's easy, for training your dog. You just have to be consistent. Also, check into how you can keep your dog in the yard or whatever so he can't get access to anyone who walks up to your house. You never know when that might happen! And keep in mind, although bullmastiff's (and any other mastiff) are sweet creatures (I have one, myself!), they can look scary and you never know what a dog might do when they sense fear!

When an animal encounters a new person, you should have your dog in a controlled situation, like on a leash. It may have been fear, a strange smell or a sudden movement that caused your dog to act in an agressive fashion. Thankfully, he just gave the "flyer-man" a serious warning with his jaws and not a full fledged bite. The flyer man was in his "domain" and your dog considers it his duty to protect the property and family from any potential threat.

We had him on his runner ( it was a reasonable length) we have shortened it since but I know a shorted leach doesnt solve the problem. He has NEVER shown any signs of agression before, not even by showing his teeth or growling as a warning, that day he just bolted right up to him as he always does to greet him( as he usually does with visitors) but insted of greeting him he bit him(his sleeve) he shook his head a little bit to. When we yelled for him to stop. he did and retreated and he was shaking, I dont know if it is because he was scared or because he wanted to go after him again. He lives with all females... He is a VERY good dog, he went to dog school, he listens to everyone. Was this a one time thing? Is it possible for a dog to be fixated on just one person and bolt like that with no warning? We have had male visitiors before.. is it becaause he thought that he was uninvited? Their has to be a reason why he did this usually when dogs pounce like that they give some kind of warning. I KNOW that when I tell him to do something he listens I want to know how to prevent this without sheilding him from everyone.. that isnt really fixing it its just covering it up for the moment. I want him to be a healthy 16 month old Bull Mastiff.