Don t pet a dog that is tied up. When a dog is in pain, he doesn t understand where the pain comes from. If you touch him, he may think that you are causing the pain and will bite you to stop the pain. The dog may feel scared or surprised. Quick movements and sudden or loud noises are scary for dogs, and they may bite to protect themselves.
Strangers can also frighten dogs.
But if a dog thinks you are a stranger who might hurt him, he may not know how to get away. So he will protect himself by biting. Watch and listen for the warnings that a dog will give you. If his ears are laid back against his head, or his legs are very stiff, he is probably warning you that he feels threatened and will protect himself if he must. If the hair on his back is standing up, that is another warning.