The funniest thing about this predicament is that your mailman may likely be doing it to themselves. Mailmen have learned over the years to deal with problem dogs, dogs who bark and chase and may even try and bite, and the most effective solution for your mailman is to bring your dog a treat. This is great for your mailman, as it relieves the stress and barking from your dog every time, but it also inadvertently trains your dog to bark at mailmen, simply because every time they have in the past they have gotten a treat. Fortunately, cases like these can be quite easy to treat and you can have your dog quiet each day the mailmen comes by… if that is what you want.
The Root of the Behavior
For thousands of years of less developed times, and even through today, dogs have been used as alarm systems. It works well and your loyal buddy does a fantastic job, but this is often the root cause to them barking at everything and everybody. You can treat this behavior and train your dog to react favorably to strangers approaching, but sometimes this might not be what you want. Nothing makes a robber turn tail faster then a rushing and barking dog, even if your dog is so sweet it would do nothing but lick them when they got close enough. In this way your dog is incredibly helpful and this protective function is very helpful. Often the human companion prefers their sleep and does not need their dog to perform this protective function, so when they do it is considered an annoyance. If you fall into this category then your probably reading to find out what you can do to change this behavior and get your dog to stop barking at every thing that comes by. There are a lot of things that add up to this behavior. Besides their innate need to protect, gained through selective breeding, your dog may simply be scared themselves. This can be from general stress or anxiety. Having a dog bed removed from the high trafficked areas of your home and isolated from the noise outside can reduce these behaviors and relieve some stress. Having some toys or games they enjoy nearby will do a lot to make this area feel like home to your four legged friends. Stress can also be caused by you and your stress levels. If you are very stressed and running around your house with high energy levels, your dog will empathize and do the same. Give them a chew toy or bone, these act as a stress reducer for dogs as the compulsive chewing is relaxing and feels good. This is also good for the health of their teeth provided the bone is not hard enough to crack them.
Encouraging the Behavior
When your mailman comes by next time, go outside with your dog. Introduce them, gain some familiarity between your mailman and dog and show them your mailman is no one to be scared of. If you would like to treat train them, have them sit and stop barking before you give them the treat. If you give it to them to distract them they learn the behavior you are trying to remove, however if you give it to them only when they stop barking, they will quickly learn not to bark. If your dog barks at everything that comes by then work on their stress levels. Your dog will naturally bark at some things, squirrels and dear, etc. However you can relieve much of this by simply closing your blinds. A behavioral specialist or trainer can come out and help develop proper training techniques for your dog to ensure the best behavior. This can be done in just a few visits by educating you on the proper steps to take to encourage best practices in your home. With some time and understanding you can instill these behaviors yourself and can easily train your dog to greet people much more amicably. Remember dogs approach people differently then people do. Pulling their leash tight makes them worry about the person you are trying to introduce them to. Let your dog approach naturally and only pull the leash taught if you are worried about a violent or destructive reaction.
Other Solutions and Considerations
Past trauma or mistreatment can make these behaviors harder to change, but with some time and familiarity with a safe environment these behaviors will become easier. If your dog is barking with violent intent it is important you take it seriously and do your best to correct it as soon as possible. Dogs can do a tremendous amount of damage and your financial well being relies on your dog not hurting someone. Your dogs life also depends on it, and in some cases, the person or dog they attack. If they have no violent intent then just some familiarity with what they bark at will help. Try not to pet or give your dog a treat to stop the barking, as this feels to them like encouragement for having barked at the target.
Training these behaviors out of your dog can be easier than you think but you should consider how friendly you want your dog to be to strangers. If a robber comes up and into your house, do you want your dog to treat him with a smile? The context of a robber is lost on your dog, and so they will likely react to the mailman the same way they would react to an intruder.