This post is part of the series in response to Dunbar’s 2012 Australian seminars. See index.

Imagine you are at the dentist and he slips with his little scratchy-hook tool, and stabs your gum a little bit.  You respond by biting down on the dentist’s finger and punching him in the face.

Or you’re asleep in your bed and you partner wakes you as she hops in.  This terrifies you, so you grab your gun from under the mattress, and shoot her.

Puppies need to be guided to learn to not use the full force of their bite as an adult dog. Photo © Ruthless Photos.

Ian Dunbar used similar human-aggressive examples in his seminar to make a point: Dog-human aggression is never okay.  Just like humans don’t (shouldn’t) hurt people that accidentally hurt them, and don’t hurt people that scare them, dogs shouldn’t hurt people in response to pain or fear.

There are simply no excuses for a dog to be human aggressive – it is never appropriate and never acceptable, regardless of the context.

First, appropriate socialisation should aim to build a confident puppy that is never fearful enough to bite as an adult dog.  Second, a puppy should be taught how to inhibit (i.e. make less forceful) their bite so that, if for some reason they are motivated to bite in their life, the bite is less severe.

Dunbar didn’t go into much detail about teaching bite inhibition at the seminar, but basically the process involves teaching the puppy to bite less forcefully and then teaching the puppy to bite less frequently (and eventually learn that they are not allowed to put their teeth on people).  Alongside this, you add a cue that means ‘let go’.  (It seems that the Dunbar seminar Crystal, at Reactive Champion, attended did talk about teaching bite inhibition in more detail.)

Furthermore, puppies that attend the Dunbar-style puppy classes, with offleash play, mean that they learn how to appropriately control their bite when interacting with other dogs.

The plan is that, after teaching bite inhibition to a puppy, the adult dog will be more likely to bite in an inhibited way.  That is, the depth and seriousness of the bite will be less severe.  A puppy that is well socialised, but does not have bite inhibition, makes for a dangerous dog.

Measuring Dog Bites

Dunbar has a scale that measures dog bites from 1-6 (with 1 being minor and 6 being a fatal dog bite).  This is a well-known scale, and seems to be have been embraced by many in the dog community.  However, Dunbar’s scale is not the only scale. For example, Blue Dog has their own.

The Scale

• Level 1: No teeth touched the skin, but the dog growled, barked, lunged, or otherwise displayed aggression.
• Level 2: The dog’s teeth touch the skin, but did not puncture the skin. (90% of dog bites fit into this category.)
• Level 3: The skin is punctured, but the wounds are shallow.  There are 1-4 holes (canine teeth in skin), maybe with tears. The bite wound bleeds.
• Level 4: The dog bite has deep punctures, and the wounds need to be flushed.  The wounds are as deep as 1.5 to 2 times the length of a tooth, and there are associated bruises, slashes, and a hospital stay.
• Level 5: The victim spends several days in hospital. They are mutilated.
• Level 6: The victim dies (a rare outcome from a dog bite).

Dogs that have bitten, but haven’t done any damage (i.e. level 1 or 2 biters) are great dogs!  We can have confidence that this dog doesn’t mean to hurt.  You could comment, “What fine control this dog has of its mouth!”  These dogs are easy and safe to work with.  If a trainer (or anyone else) ‘stuffs up’ when working with them, it’s not going to matter too much.

A dog that is a level 3 biter is more serious and should be approached with caution when undertaking behaviour modification training.

According to Dunbar, a dog that bites on the upper side of this scale is too dangerous to rehabilitate.  He believes that dogs that bite at a level 4 and up should be euthanised, for the sake of their breed and dogs in general.

Dunbar gets frustrated when people ask whether a dog’s situation warranted the bite.  He made his point by describing scenarios where dogs were in extreme pain, but only level 1-2 bites were instigated by the dog.  These dogs are unlikely to administer a ‘bad bite’, regardless of circumstances.  According to Dunbar, a level 4+ biter will always be a level 4+ biter, and this is what makes them dangerous.

Further References

Ian Dunbar, with his wife and son, have a recording concerning bite inhibition and it’s importance for determining how dangerous a dog is.  If you’ve enjoyed reading this article, you may also be interested in listening to The Bite Scale and How to Evaluate Aggression.

Dunbar has a video on “Mr Mousey and Mr Carcus” showing dogs how to interact with different toys in different ways.  The hope is that this dog will generalize your instructions and treat living animals (like a kitten) like they treat the toy they have to be gentle with.