Does your dog chase strangers? Not all dogs do, but there are others who, when an unknown person calls at the house and you happen to open the door, will fly out and chase that stranger down the sidewalk. It can happen too when you're out taking your dog for a walk. One minute he's calm and happy, just having a sniff around and the next he's legged it at the speed of light chasing after a stranger. It may be a jogger or even another dog walker who came just that bit too close.
So what is it that incites dogs to chase strangers?
The Root of the Behavior
Your dog has a strong proprietorial emotion about what he classes to be his territory. If he'd still been in the wild and a strange animal had wandered into what he believes to be his personal kingdom, it would for him signify a major problem. That unwanted interloper could attack him and take what's his. He can't allow that to happen and would be forced to chase the intruder away for his own self-protection. A stranger, appearing at the door, is to him posing a very similar threat and it's one he's just not about to tolerate.
All dogs have their own individual personality. In some ways, they're a lot like us humans. While one dog may have outgoing characteristics and enjoy mixing with unknowns, others, just like people, can be downright anti-social. Some dogs just don't like strangers or anyone who is outside of their regular intimate circle. For them there's one easy solution to rid themselves of the intrusion to their privacy and that's to chase it off.
Dogs are sensitive beings. It's how they've managed to survive through the centuries. Reading a situation and reacting to it according to canine law is part of their self-defence system. You are part of his pack. If he senses that you are feeling anxious about the stranger who is approaching or has started rattling the letterbox, he's not going to let the moment pass without going into protection mode. He senses your uncertainty, maybe even fear, and he will attempt to chase away the stranger who he sees as a threat to you.
It is natural for dogs to chase things. It is biologically ingrained in them for their own survival. They chase prey to fulfill a need for food and they chase strangers, be it in human or animal form, who they class as a prospective menace to rid themselves of the imminent danger.
Encouraging the Behavior
Dogs love to chase things, from balls to chickens. If it moves, they'll go after it. When what they chase is a person, albeit a stranger, it can cause some serious problems. Let's face facts. The stranger your dog is chasing doesn't know your pet and is not running away for no reason. The stranger is running because he's afraid of your dog and scared he might get bitten, which for that person is not a pleasant emotion to have. You might know your dog is the softest mutt in the world, but they don't and if the situation escalates, your dog could end up being labeled as dangerous when he's actually completely the opposite.
Dogs have one cardinal rule for things that move and that is chasing it. If you're somewhere with your dog where people are running, in the park or at the beach, he might not feel particularly threatened by the fact that they're strangers, but he may well feel inclined to give chase and tag along behind them. Joggers are not fond of dogs snapping at their heels and it can be dangerous because your dog can unwittingly trip them up, causing injury to them or even your pet if they land on top of him. If you know you're going to be in a place where there's likely to be runners, it's much better to keep your dog on a lead.
Other Solutions and Considerations
Although it's in a dog's nature to chase a stranger it really is much better if they don't do it. If you know who the stranger at the door is, even though your dog might not, it'll be much better for all of you if you put your dog in another room before opening the door. It'll save you, your dog, and the stranger an awful lot of stress. If your dog chases strangers who are in the park running, you might want to consider taking your pet to some professional training sessions. A qualified dog trainer will be able to teach you how to manage your dog's need to chase. They'll also help him differentiate between who constitutes a threat and who doesn't.
If your dog chases away a stranger who comes knocking at your door with bad intentions, all is well and good. He's doing his job of keeping you safe from harm and looking after your home. It's not so good if that stranger just happens to be the pizza delivery guy who's dropping off your favorite thirty-six inch pepperoni with extra cheese. In fact, that's not funny at all.