There are many ways of categorizing a dog bite, but Dr. Ian Dunbar’s Dog Bite Scale is the most commonly used method. Below are the six dog bite categories:
Level 1: At this stage, a dog is displaying clearly aggressive behavior, but there is no skin contact with its teeth. A dog at Level 1 is simply trying to scare away a person or another dog.
Level 2: The dog is becoming aggressive. There is now skin contact with a dog’s teeth, but the victim’s skin is not punctured. At this point, a dog is showing that it is willing to increase its aggression to let you know it doesn’t want you around. (Level 1 and 2 bites are the most common and make up 99% of all dog bite incidents. However, dogs at Level 1 and 2 are not dangerous and can be trained with relative ease).
Level 3: The dog now presents a serious threat to others. In order to count as a Level 3 attack, there must be one to four tooth punctures from a single bite, and no puncture can go deeper than half the length of a dog’s teeth.
Level 4: The situation has become very serious and a dog must be kept away from others. A Level 4 attack includes one to four punctures from a single bite. One puncture wound must also be deeper than half the length of the dog’s teeth. A Level 4 dog bite victim may develop bruising around the wound if the dog was shaking its head from side to side when it bit down.
Level 5: A dog at this stage is dangerous and rehabilitation efforts are usually unsuccessful. Multiple bites and serious attacks are commonplace. This dog is not safe around anyone. At this point, euthanasia is recommended because of the danger the dog poses to others.
Level 6: This stage is very rare, and someone, whether the animal or the victim, is killed in the attack.