Why Do Dogs Guard Vehicles?
First, realize that you can be bitten by a dog in a vehicle. It doesn’t matter if the dog is a Chihuahua or a Mastiff, when that dog barks, growls or shows you his teeth he is just as serious as a dog who is defending his home. In fact, as far as that dog is concerned he is defending his territory. He may not be in his house but he is defending his owner’s property and he knows it.
If you want to avoid being barked at or bitten, you should look at the situation from the dog’s point of view and take it seriously. You may be trying to be friends but the dog is guarding his owner’s property.
Even for dogs who may be relaxed at home when someone comes to the door, when they are in a vehicle they may be in a strange place, such as a parking lot. They are surrounded by windows which may make them nervous. When a stranger approaches they will act defensively. At the very least they will bark. If a stranger tries to reach inside and pet the dog, he may very well bite.
If your dog becomes protective of the car while you are still in it, you should be able to tell your dog to stop and he should pay attention to you. Your dog should be able to relax in the car when you are present even if a stranger approaches. You need to be able to speak to people when your dog is in the car without him overreacting.
When it comes to dogs who guard their vehicles when the owner is away for a few minutes, this is a normal dog behavior. Your dog believes that he is protecting his territory and the owner’s property from a potential intruder. It’s not wise to disturb a dog in this situation.
Please remember temperatures rise quickly in parked cars, please do not leave your dog unattended, even for a few minutes during times of extreme heat.