People may know if the dog has already been seen growling, snapping or biting. This may be a dangerous dog and bite people. Dogs can show if they are going to bite because of how they stand and act. People can learn how to see how the dog looks and act. People can learn the body language of dogs and know when the dog might bite. If the dog is snarling, has a wrinkled nose, eyes that are black, and fur that stands up, the dog is dangerous and might bite.