There are a number of reasons why dogs will always bark at the door, even when it seems pretty obvious there is no reason to do so:
- An interruption. Whenever the doorbell goes off, it is a sign that something new will happen. It signifies a sudden alteration in the way things are at the moment. Maybe your dog was playfully chewing away on some toy so excitedly or chasing your kids' ball around the house and now the activity is likely to stop because something different might begin. The dog might have been asleep and was rudely woken up by the annoying sound of the doorbell. However you choose to interpret this interruption, is still boils down to the fact that a very important activity was altered by that sudden interaction. I believe it is enough reason for your dog to start barking at the door.
- An attempt to make you aware. If you are not somewhere your dog can easily see you or how you reacted to the sound from the door, she might try to make you aware of the intrusion in case you are not paying attention. Barking is one way it can bring to your notice that there is someone waiting at the door to be let into the house or for you to take whatever appropriate action that suits the situation.
- Dogs have the ability to link whatever sound they hear to whatever activity they notice immediately after the sound goes off. In the dog's past experiences, the sound of the doorbell often precedes an immediate response like unlocking the door. To the dog, the sound of the bell as it rings and the door opening that follows it goes with the entrance of either a visitor or a member of the family who has been away from the house. All your dog tries to do is to alert you about someone trying to enter your home.
- Curiosity. This might seem to relate to the attempt made by your dog to warn you about the fact that you need to do something fast about the person at your door. However, it does not. With some dogs, barking stops immediately they see you are headed towards the door in question. With others, the barking continues. The dogs that continue their barking even after you are about to open the door do so because they are not sure what to expect from the closed door. They might think something sinister waits you behind the locked door. We all know how social dogs can be and how much interaction they often seek. Whenever the sound of the doorbell goes off, there is a possibility that whoever wants to come in would pet them, scratch their ear or at least fool around with them a bit.
- Protection. Your dog probably loves everything about his home, including the people in it. The sound of the ringing doorbell certainly means that there is someone at the door with the intention of disrupting his quiet environment. My dog barks at the door to warn whoever the intruder might be that the house is his territory. According to the United States Humane Society, the dog stands up, holds his tail a bit high, and perch his ears in a forward position if he feels there is an immediate threat to his territory. Some dogs bite when they feel threatened, so never try to pet your host's dog if you find him displaying some aggressive behaviors when you go visiting.
- Fear. Most times, a barking dog is simply trying to tell you how scary the sound of the ringing doorbell is to him. Dogs always associate the sound of the doorbell with the unpredictable and unknown. What waits you behind those closed doors? Would whatever it is pose any danger to members of the family? Dogs very protective instincts, which makes them much concerned with the safety of their owners and human companions.
To stop such aggressive behaviors your dog displays when threatened, check out the link below:
http://www.cesarsway.com/dog-behavior/barking/Dog-Barking-101