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Dogs and Bites

Updated: May 27, 2020

This document is meant for informational purposes only. I hope to lay out for the reader the issues at play with a dog that has bitten or shows behaviour that indicates a bite is likely.


• Any dog can bite given the right circumstances and provocation

• Most bites are the result of a dog that is fearful or anxious, but not all

• According to the statistics collected by Kenneth Phillips (, 61% of bites occur in the home or a familiar place with 77% of the bite victims being family members or friends.

• Dogs generally go UP the bite scale. If a dog’s first bite is a level 3 or 4 (bite scale will be presented later), they are unlikely to go down the scale.

• The more time the dog has had to practice aggressive responses, the longer it will take to modify them.

• Very few bites are actually “out of the blue”. Almost without exception, dogs have previously presented early warning signs that have gone unrecognized or ignored.

• As horrific as a dog bite can be, they DO give us useful information upon which we can act.

• ALL bites need to be taken very seriously regardless of the level of damage done.

• Dog mouths on human skin should generally be discouraged. Obviously, puppies will do this and we have to train them not to. But adult dog mouth on human skin can end badly. A dog who takes a treat roughly will need to learn to gentle their take.

• “Normal for the breed” is not an excuse for dogs that are biting, nipping, mouthing.


• Overly aroused. Dog is way over threshold (sometimes from rowdy play/excitement and sometimes from stress) and does not have the ability to bring his/herself down. This can result in mouthing, nipping, grabbing clothing, biting ankles and butts. This is the classic “What starts in laughter ends in tears” scenario Re-directed aggression: Dog is over threshold, usually overly aroused in a stressed way, you got in the way or attempt to redirect the dog and the dog redirects on you by biting.

• Over tired/sleeping/not feeling well/vision or hearing deficits. Dog is unable to tolerate being annoyed (and sometimes that is as minor as petting or sitting near dog) and the tiredness, sleep state, illness or old age has reduced the dog’s inhibitions. Some dogs will bite when startled.

• Dog fights. Breaking up a dog fight is often a guaranteed dog bite. This is both related to redirected aggression and over arousal

• Resource guarding. Dog has something they consider valuable and will defend it, sometimes vigorously. The dog determines what is valuable, not the humans. I’ve seen a dog bite a human over a stick. Dogs can resource guard food, toys, space, a human, territory.

• Threat response. This is one of the more common reasons for a dog bite. The dog perceives a threat and responds by biting. Generally, this is a situation in which the dog has used lower level signals that they feel threatened and those have been unrecognized or ignored. The dog determines what they consider threatening, not us. So a dog that has been okay with a visitor sitting quietly on the sofa may not be okay if the visitor stands up or moves. The number of things that a dog can perceive as a threat are as variable as the dog. Being cornered or trapped is a good’s why some dogs are reactive on leash but not when off...they feel trapped by the leash as it eliminates the “flight” option.

• Offensive aggression. This is fortunately somewhat rare. This is a dog who is actively seeking to get closer to something/someone in order to bite. This dog is actually WANTING to get closer as opposed to trying to get further away. This dog is not responding to what they perceive as a threat. Instead, the dog is an active threat. To some degree, predation falls into this category. The body language in an offensively aggression is VERY different from a dog that is defensively aggressive.

• Genetic issues/idiopathic aggression. Some dogs are simply wired wrong, have such bad genetics that the aggression displayed will likely not respond to behaviour modification.


The bite levels below are based on Dr. Ian Dunbar’s Bite Scale, but have been somewhat expanded by Dr. Sophia Yin.

Level 1 (pre-bite): the dog snaps or air bites but makes no contact with the person. Now people tend to say, “The dog tried to bite me but I moved away.” I say, “Give me a break.” Humans have sloth-like reactions compared to the speed of a biting dog and dogs have pretty good aim when trying to grab things. If the dog actually meant to bite (rather than just give you a warning), you would have the holes to prove it. Owners should take this air snap as a sign that someone wasn’t paying attention to their dog’s earlier signs of displeasure or fear. Owners should get help before this sort of pre-bite behavior progresses to an actual bite. Avoid punishing these warning signs or the dog may progress to biting without warning.

Level 2 (near-bite or highly inhibited bite): the dog snaps and makes tooth contact on skin but there’s no actual puncture. Often the dog runs up to or lunges for a person but just puts front teeth in contact with the skin in a sort of near-bite. In other cases, the dog actually opens his mouth and clamps but in an inhibited manner such that no skin is broken. Again the owners should ask, “What earlier signs did we miss to warn us that this could happen?” The owners should realize, the near-bite or inhibited bite could turn into a real bite down the road.

Level 3A: the dog bites once and punctures skin, but the puncture is shallower than the length of the canine tooth. Even though this bite may not be severe, it is still reportable. And painful, too. Reporting is mandatory if the victim is treated in a hospital. Once your dog has actually bitten at this level (or higher) he will always be considered a liability, even if, with behavior modification, he is 99.9% improved.

Level 3B: the dog bites multiple times leaving skin punctures shallower than half of the canine. Multiple bites generally mean the dog is in a higher arousal state. That is, the dog is reacting without thinking between bites.

Level 4: the dog bites once with punctures deeper than the length of the canine (the dog bit and clamped down) or the bite produces slashes in both directions from the puncture which indicates that the dog bit and shook his head. This type of bite is very serious. While any of the lower bite levels should act as a neon sign telling the owners to seek help from a qualified and educated behavioral modification specialist, the level 4 bite says, “Man, you should have gotten help three years ago. This has been building up even longer than the level 3 bites.” Level 4 bites are way harder than level 3 bites and now show no inhibition in strength. A dog biting at this level presents a screaming liability to the owners, both in terms of money and family members because this type of bite can kill a child.

Level 5: The dog gives multiple bites with deep punctures. Dogs who bite at this level generally have had practice biting at levels 3 and 4. Some dogs are so fearful that a scary event triggers a high arousal state and they get stuck in a reactive mode, continuing to bite hard.

Level 6: The dog kills the victim or consumes their flesh. It’s important to realize that even little dogs and puppies can bite hard enough to kill infants and small children, just the way little knives can. Dogs can bite this hard due to fear, but they can also bite and cause death due to over aroused play.


First and foremost, you need to get a professional to help you if your dog has bitten. A risk assessment is needed so that you can assess what your options are.

A risk assessment will look at the following in order to determine how much risk is involved with this dog:

* Age of onset/duration of the behaviour

* Specificity of the behaviour vs Generalization to other contexts and stimuli

* Presence of visible/discernible warnings

* Predictable patterns of behaviour

* History of Harm/Severity of harm

* Degree of inhibition/arousal level

* How quick is the “trigger”

* How likely would unintentional provocation be

* Are the owners/family afraid of this dog

* Is management reasonable/possible and likely

BEHAVIOURAL REHABILITATION/MANAGEMENT: This generally will require the help of a professional behaviour consultant or a veterinary behaviourist in order to set up an appropriate plan so that everyone stays safe, the treatment work can get done, and the dog may have a reasonable quality of life.

MUZZLE TRAINING: This is technically part of management. I think ALL dogs should be muzzled trained, not just reactive dogs. BUT any dog that has bitten or has a high risk for biting should be muzzle trained.

RE-HOMING: This CAN be an option, but it is fraught with risks to you, to the dog and to the new owner. A dog that has bitten is a legal liability and you may not be able to walk away from that liability. Re-homing a dog that bites children to a childless home does NOT mean that dog will never encounter children again.

You may not be able to ensure that your dog will be handled/managed/trained appropriately. Many people WILL sign up to take on a dog that has bitten and resort to using aversives.

The Happy Dog Farm in the country is most often a myth. Sure, some dogs ARE happier in the country....but having grown up on a farm in rural Kentucky, I can assure you that there are lots of roaming dogs, livestock, delivery people, noises from large farm equipment, etc in that environment.

Is there another home out there? Just because it may be possible for a dog to be rehabilitated in a specific type of environment doesn’t mean that it is available. Just because someone is willing to take on your dog and his/her issues doesn’t mean they have the skills, abilities, money or insurance to do so.

EUTHANASIA: Absolutely no one likes to talk about this option. But it is an option and is an option that should be seriously considered when the other two options are not available or the risk assessment of the dog is that the dog presents serious risk. This kind of decision is often brutally hard for owners to make, but needs to be on the table for some dogs. Quality of life for everyone needs to be considered. Some management of aggressive dogs may keep the dog alive, but does not allow the dog to live much of a life.


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