How Helpful are “Bite Levels”?

We've recently seen several popular "Bite Level" categorization schemes that we assume are supposed to assist users in determining the relative degree of danger dogs that bite present.  "Bite Level Hierarchies" are based attempt to relate the dog's biting behavior to the type of injury caused.

We question the usefulness of these schemes and believe they can actually distort the accuracy of the risk assessment they are being used to create.  To understand why, let's discuss what's involved in risk assessment.

The seriousness (or put another way the risk a dog presents) of a dog bite is influenced by at least three factors:  the dog, the target of the aggressive behavior, and the context.  Risk cannot be adequately assessed by ONLY considering the end result – the type of injury.  Let's look at a few examples.

Spot, a 3 year old spayed female Dalmatian bites a visitor to the home who is reaching out to pet him.  The visitor is Jim, a 30 year old male friend of the family, and the bite leaves a red mark and a small indentation on the man's forearm. 

Next, Spot bites the family's 86 year old grandmother under the same circumstances and with the same intensity.  However, at age 86, Grandma's skin is more fragile than Jim's, and Grandma is on "blood thinners".   So this same intensity bite results in a wound that breaks the skin and bleeds.  Because Grandma's immune system isn't as robust as a younger person, the wound becomes infected resulting in more extensive medical treatment.

Schnitzel a 5 year old neutered male Miniature Schnauzer loves all adults but is afraid of and defensively aggressive towards children.  A 4 year old child of average height is about at face level with Schnitzel, and he is such a cutie that children immediately want to pet him.  When 4 year old Sally did just that, Schnitzel bit her in the face.  Even more troubling, is that Schnitzel gives no warning before he bites – he allows a child to touch him before he goes for the face.  Schnitzel didn't bite hard enough to leave a puncture wound, but unfortunately when he bit Sally a tooth just snagged  the tear duct in her eye.  In another location, the bite would have barely broken the skin but repair of the tear duct required surgery. 

Finally there is Oz, the 8 year old neutered male Australian Shepherd.  Oz has always been afraid of people and avoids visitors.  He has never bitten anyone, never shown any aggression or threatening behavior, preferring instead to retreat and not interact.  Oz is very responsive to treats, and his owner is very good at managing him, even at the veterinary hospital.  In the owner's absence, a pet sitter tried to grab Oz by the collar to make him go outside to relieve himself.  Oz growled at the sitter who then grabbed Oz by the scruff of the neck and tried to pin him to the ground.  Oz turned his head and was able to get the tip of the man's thumb between his molars, biting it off. 

Dog to Dog Bites

The same problems arise when attempting to apply a "bite level" scheme to the injuries caused by dog to dog aggression.  A medium sized dog, for example a Border collie could deliver the same intensity bite to an Italian Greyhound (I.G.) and a Siberian Husky and do far more damage to the former than the latter. 

At the same time, perhaps the reason for the bite to the I.G.  was because this smaller dog was into the other dog's food bowl, but the bite to the husky was when both dogs were running toward the front door after hearing the sound of the doorbell.  Most folks would view the first context as more "justified"  or "normal" – a dog protecting its food.  The second context on the other hand was not related to any direct interaction, competition or threats between the dogs – just a high arousal context. 

All these examples illustrate why considering both the context and the target of the aggression is crucial in assessing risk and why focusing on the level of injury can be extremely misleading.  Bites of the same or similar intensity can result in very different injuries, depending on the characteristics of the victim.  Bites that occur in unacceptable circumstances based on society standards – someone reaching out to pet a dog – present far more danger than bites that happen when someone is purposefully intimidating and threatening a dog.

The Nominal Fallacy

We've discussed the nominal fallacy in many of our courses – the mistaken belief that if you name or label something you've helped to explain it.  This holds true for "bite levels" as well as terms such as "prey drive".  Those who become involved in dog aggression cases – the courts, attorneys, insurance companies, animal control officers, animal shelters, rescue groups and more – can all best benefit from full and complete descriptions of the aggressive episode rather than short-cut terminology.  None of these groups have a common terminology, nor is it likely they ever will have. 

So – which gives you more information?  "The Level 3 dog bite to the jogger was motivated by prey drive"  OR "The dog bit the jogger one time in the lower leg as the man passed the leashed dog walking with his owner, resulting in moderate bruising and 2 puncture wounds – photo attached."  We could add even more detail, but you get the point.