Ian Dunbar's Dog Bite Scale
Updated: Aug 28
Being bitten by a dog is frightening. If the dog who bit was your own, it's heartbreaking as well — you may be replaying the moment, wondering whether you missed something, and asking yourself whether you can still trust your dog.
Dogs don't bite without a reason. Our job is to work out what that reason was, so we can keep everyone safe and help your dog feel differently about whatever triggered it.
If your dog has bitten, you don't have to work this out alone. Our certified behavior consultants take bite cases, including the ones other trainers turn down. Learn about our fear and aggression work.
Has your dog bitten someone?
If you're reading this because it just happened, take a breath. You're not a bad owner, and your dog isn't a lost cause. Bites almost always have a reason behind them — and understanding that reason is the first step to making sure it doesn't happen again. We're a team of credentialed behavior consultants in the Dallas–Fort Worth area, and bite cases are what we do. Our founder, Nicole Kohanski, is a NACA certified level 2 Animal Control Officer and holds many behavior credentials including CBCC-KA, CDBC and CTC. She works specifically with complex fear, anxiety and aggression cases. We'll be honest with you about what's realistic. And we won't judge you for asking. We see clients in person in DFW Metroplex, but we can help you virtually if you live anywhere. self-schedule a free call or call or text 469-444-1474
What the bite scale measures
Dr. Ian Dunbar's Dog Bite Scale assesses the damage a dog actually caused, not how frightening the incident felt.
That distinction matters more than almost anything else in this article. A dog who lunges, barks and makes contact without breaking skin is telling you something very different from a dog who punctures deeply. Both are terrifying to experience. They are not the same problem, and they don't have the same outlook.
The scale gives us an objective starting point — a way of describing what happened that doesn't depend on how scared anyone was.
The six levels
Level 1 — No skin contact
Obnoxious or aggressive behavior, but the dog's teeth never touch skin. Barking, lunging, snapping in the air, growling.
Many owners don't think of this as a "bite" at all. It is worth taking seriously — it's your dog telling you they're uncomfortable, and it's the easiest stage at which to help them.
Level 2 — Skin contact, no puncture
The teeth make contact with skin but don't puncture it. There may be small nicks and slight bleeding caused by the teeth moving sideways or forward across the skin, but no downward puncture wounds.
Level 3 — Shallow punctures
One to four punctures from a single bite, with no puncture deeper than half the length of the dog's canine teeth.
There may be lacerations in one direction — usually caused by the person pulling their hand away, someone pulling the dog back, or the dog's own weight as it drops.
Level 4 — Deep punctures
One to four punctures from a single bite, with at least one puncture deeper than half the length of the dog's canine teeth. You may also see deep bruising around the wound, which means the dog held on and bore down, or lacerations running in two directions, which means the dog held on and shook.
This is a meaningful step up from Level 3. The dog has bitten with real force.
Level 5 — Multiple deep bites
A multiple-bite incident with at least two Level 4 bites, or a multiple-attack incident with at least one Level 4 bite in each attack.
Level 6 — Fatal
The victim dies as a result of the bite.
What this means for your dog
Levels 1 and 2 account for the overwhelming majority of bite incidents — well over 99%. If that's where your dog sits, the outlook is genuinely good. A dog at this level has excellent bite inhibition: they made a deliberate choice not to do damage, even while frightened or angry enough to use their mouth.
That inhibition is not something we can easily teach an adult dog. If your dog already has it, you're starting from a strong position.
Level 3 generally carries a good prognosis with proper assessment and a well-built behavior plan.
Levels 4 through 6 are more serious. The dog has demonstrated that they will do real damage, and the plan has to prioritize safety and management alongside behavior change. That doesn't automatically mean a dog can't be helped — but it does mean you need a qualified behavior professional involved, and you need honest conversations about what management will look like long-term.
A single number never tells the whole story. Frequency matters. So does what happened immediately beforehand, who was bitten, whether there were warnings, and what the dog's life looks like day to day. Two dogs can both be "a Level 3" and need completely different plans.
What to do right now
Care for the wound. Dog bites carry real infection risk. Seek medical attention, especially for punctures.
Give your dog space. Separate them from whatever triggered the bite. This isn't punishment — a dog who has just bitten is usually still stressed, and stressed dogs make worse decisions.
Write down everything while it's fresh. Details fade fast, and the details are what let a behavior consultant work out the why.
Check your local reporting rules. Requirements around reporting dog bites vary by city and county across Texas. Your veterinarian or local animal services can tell you what applies where you live.
Don't punish your dog for growling. It's the most common instinct and one of the most counterproductive. A growl is a warning — a dog telling you they need more space. Punishing the warning teaches them to skip it next time, and a dog who bites without warning is far more dangerous.
What your behavior consultant will want to know
When we assess a bite, the wound is only the starting point. These details tell us far more:
What happened in the seconds immediately before the bite?
Where were you, and who else was present?
What were you or the person bitten wearing or carrying?
Did the dog give any warning — freezing, a hard stare, lip curl, growl, whale eye?
Had anything unusual happened that day? A vet visit, houseguests, a change of routine, poor sleep?
Has anything similar happened before, even at a lower level?
How is your dog's health? Pain is an underestimated driver of sudden aggression.
If you can, write these down before your first consultation. It makes an enormous difference.
Frequently asked questions
What is a Level 4 dog bite? A Level 4 bite is one to four punctures from a single bite where at least one puncture is deeper than half the length of the dog's canine teeth. There may be deep bruising, meaning the dog held on and bore down, or lacerations in two directions, meaning the dog held on and shook. It indicates a dog who bit with significant force and poor bite inhibition.
Can a dog who has bitten be rehabilitated? Often, yes — but it depends on the level, the frequency, the circumstances and the household. Dogs at Levels 1 to 3 frequently do very well with a proper behavior plan. Higher levels need a more careful approach with management built in permanently. What we can promise is an honest assessment rather than false reassurance.
What is bite inhibition, and why does everyone keep mentioning it? Bite inhibition is a dog's learned control over how hard they use their mouth. Dogs develop it in puppyhood through play with littermates and people. A dog with good bite inhibition may still bite when frightened, but does far less damage. It's the single biggest predictor of how well a bite case is likely to go.
Does one bite mean my dog will bite again? Not necessarily. Behavior that has happened once can happen again if the same circumstances recur — which is exactly why identifying the trigger matters so much. Many dogs bite once, in a specific situation, and never again once that situation is understood and managed.
Should I rehome or euthanize my dog? This is one of the hardest decisions a dog owner can face, and it isn't one to make in the first frightened days after an incident, or based on a number on a scale. Get a qualified behavior assessment first. A good consultant will talk you honestly through what's realistic for your dog, your household and your capacity — including when the honest answer is difficult.
Do I have to report a dog bite in Texas? Reporting requirements vary by city and county. Your veterinarian or local animal services department can tell you what applies where you live. Medical providers often have their own reporting obligations as well.
How soon should I get help? As soon as you're able. Bite cases are easier to work with when the pattern is still short, and early management prevents the dog rehearsing the behavior. Rehearsal makes behavior stronger.
How is the Dunbar scale different from other bite scales? Several assessment scales exist. Dunbar's is the most widely used because it's based on observable wound damage rather than subjective impressions of how scary the incident was. We've put together a free eBook comparing the two most common scales, with body language guides and checklists for both the owner and the person bitten.
We can help
If your dog has bitten — or you're seeing the warning signs before a bite and want to get ahead of it — reach out.
Our behavior consultants work with fear, reactivity, resource guarding and aggression across the Dallas–Fort Worth area, including dogs with a bite history. We also work virtually with clients worldwide. We'll give you a clear assessment and a plan your household can actually follow.
Schedule a free Q&A call · 469-444-1474 · Learn about our behavior and aggression services
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