Examining Bite Severity

I have been lucky to see Dr. Ian Dunbar lecture a couple of times.  One lecture topic dealt with bite severity and the willingness/ability for a dog to control his jaw strength.  Understanding bite levels and severity is important for trainers, owners, rescuers, and veterinarians.  This is based on Dr. Dunbar’s work and how I apply it in my program.  Then the late Dr. Sophia Yin built upon Dr. Dunbar’s work.  She added great graphics too.  When typing this, I looked on-line for pictures showing different bite levels.  Some of the Level 4 – 5 bite pictures were horrific.  Therefore I decided not to add them.  However, I do have Dr. Yin’s great dog bite poster which is a lot less disturbing to look at.  I have taken parts of it to illustrate this blog.  The entire poster is available on her site for anyone to download for free.


This piece will help you determine the ability of a dog to control his jaw strength during situations. It does not matter if you are breaking up a fight, playing or have tripped over your dog and were nipped.  A dog needs to learn how to control his jaws.  Learning bite inhibition happens at puppyhood with littermates and the mother first and with the first humans in a dog’s life.  The younger a dog is when he learns to control his jaws, the better.  It becomes harder as a dog grows to teach good and more reliable bite inhibition.

This scale goes for bites to humans and other animals when we look at severity.  Now, if you have a dog that is aggressive towards other animals, he can still live a good life as simply your companion.  Dogs do NOT need to be in the company of other dogs in order to live a quality life.  If your dog is animal aggressive, be realistic.  Understand places like dog parks and dog dense activities are not good ideas.  If you are willing to accept and understand how to teach him good manners while walking and how to ignore other controlled dogs AND if you are willing to work to avoid situations, your dog aggressive dog can go on walks in carefully chosen areas.

Also muzzle training with dogs who are biters is important.  All dogs should learn to wear a muzzle just in case…  Please visit the Muzzle Up Project for more on muzzles.

On to looking at bite levels and how I apply them in my work.


The following levels are pretty easy to work with if the owner is willing to do the work.  If a dog is worked with in a meaningful way from the moment the behaviors are seen, these levels can be handled.    I would rather a dog with 100 Level 1 or 2 bites to his name than one with a couple of level 3 and above. The dog with more lower level incidents is showing me he is willing and able to control his bite.  This is a good thing.

Level 1 – Air snap, dog has great inhibition, he is warning, he is withholding his bite.  A dog can move much faster than a human.  If a dog wishes to connect and do damage, he will.  You did not move faster than the dog, he CHOSE not to bite or connect.  Getting help at the air snap/pre-bite level increases the chance of successfully working with the dog – provided all protocols are followed.

LVL 1 bite

Level 2 – Connected, small marks left, no skin breaks or minor scratching in one direction caused as the human pulled away, the dog was pulled away or a small dog slipped off the victim due to gravity. You need to work with dogs when this level is seen.  Do not wait for the dog to escalate or see if he does it again. Once the bites escalate past Level 2, it gets more difficult.

LVL 2 bite


This next level, 3, is a gray area. The dog has less bite inhibition and has done damage and probably will again.  If there are children in the house, this dog should not be in the house.  Placing a dog like this is a higher liability.

However if there are no children in the home, if all adults are willing to follow protocol, etc., this dog may be able to stay in the home depending on the management and work done.  By able to stay in the home I do not mean he will fully rehabilitate and be a best buddy to all.  I only mean he may be a dog you can adjust to live with as long as you are understanding, willing to keep up with management and work.  If you are unwilling to do the work then the dog should not stay in the house.  Again, remember placing a dog like this is a liability for all involved.  Make your decision what to do carefully.  This is from a rescue website about the issue with biting dogs and rescue.

Level 3 – One to four punctures and no puncture is deeper than 1/2 the length of the canine. There may be tearing in one direction as the victim pulled away, the dog was pulled off or a small dog fell off due to gravity.  Basket muzzles are a necessity for safety.

LVL 3 bite


In my opinion, these last three levels should not be worked with by the average to even above average dog owner.  The liability and risk are too high.  Management needed will make you all but a prisoner in your home.  These dogs have done significant damage and euthanasia is often recommended. The bite of this severity or worse may/will happen again.  Sadly there are rescuers and owners willing to place dogs who have done such serious damage in homes.  These dogs are not suitable for pet homes.  These are what some call “project dogs.”  These are the dogs that are best owned by a serious trainer with the ability to protect society from the dog while still meeting the dog’s individual needs in a humane way.  This is not an easy home to find.  A little love and caring will not cut it and cure the dog.

These dogs need owners who are willing to make the property a fortress if needed, forgo visitors if needed, use crates, gates, muzzles, and whatever is needed for safety. Again, these dogs need to be owned by good, professional dog trainers or an owner who is willing to develop the skills needed for the life of the dog in order to keep the dog and society safe.  The cost is high both financially and emotionally with these dogs.

Yes sadly, and frighteningly there are rescue groups in far too great a number that are trying to adopt out dogs with the next three levels of bite.  There are owners who are willing to lie about bite severity in order to get a dog rehomed.  Not all dogs will show the behaviors for which they were given up when in a rescue situation.  Please, if you are the owner of a dog who has bitten to any of these levels, do not rehome him.  The risk is too great.  I have sat with clients as they agonized over what to do with a dog who is a severe biter.  I have spoken to vets who feel if a dog is physically healthy, save the dog.  Well, mental health is a major concern and a dog who is willing to inflict serious damage is not a dog that is a safe or sane companion.  Also local laws play a factor.  That next bite may be the one that the law steps in and takes any option you have away.  Would you rather be with your dog at the end or have the dog put down by someone else?   This is a good piece I ask you to read.

Now on to the last three levels of bite:

Level 4 – One to four punctures, with at least one being deeper then 1/2 the length of the canine tooth, with or without tearing. Tearing is in both directions from the wound as the dog shook his head.  May have deep bruising, the dog bore down.LVL 4 bite

Level 5 – Multiple level 4 bites to one or more victims.LVL 5 biteLevel 6 – Fatality.LVL 6 bite******

I will state I have angered people when I discuss what to do with a dog that bites.  I have several rescuers who are so angry with me that they refuse to send clients my way.  A couple have even left bad reviews because they were angry clients decided to return or euthanize (only a few) dogs that were significant biters and placed with that knowledge. However, they are not the ones sitting with a client forced to make the hard decision because the dog they recently adopted has begun biting seriously. I have sat and listened to owners who felt a dog that had mauled several people – sending two to the hospital and several to doctors – would be a fine pet for a different owner if they could get a child to let them give up the dog.  I am an obligation not only to my client but to the rest of the community.  If a dog is a danger, I need to make that known.  I need to counsel owners about the liability, work needed and risks when a dog bites.

Proper choice of the best dog for you, careful choice of the source of your dog, careful training and socializing will all help reduce the risk of a dog bite.  Having those interacting with your dog do so in good ways will reduce the risk of a dog bite.  Understanding stress signals in dogs and being willing to advocate for your dog’s behavioral needs will reduce the risk of a bite.

Dogs are dogs.  They will bite if they feel the need to.  We need to work to prevent bites, address concerns sooner rather than later and be willing to make that hard decision when we are faced with a seriously biting animal.

Karen Peak is the owner of West Wind Dog Training and The Safe Kids/Safe Dogs Project in Virginia.

This entry was posted in Uncategorized. Bookmark the permalink.