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Bite proof muzzles? Truth or Myth?



As muzzle brands, we are working alongside dogs that may pose a significant risk to themselves, or to others. Which means the stakes are high if you believe that a muzzle is ‘bite proof’, only to later learn that your dog can still bite. So, it is our point of view that muzzle brands (or those that recommend those brands as ‘bite proof’) should not be declaring muzzles to be ‘bite proof’ because they think a muzzle is strong, or they have had feedback from customers that dogs have attempted unsuccessfully to bite through their muzzle, in order to get more sales. 



What does ‘bite proof’ even mean?

‘Bite proof’ is made up, with no dictionary definition, no outlined parameters and therefore no minimum standard. So in theory, any brand could call themselves ‘bite proof’ because there is no criteria for them to meet. There is no muzzle equivalent to the car harness’s crash test, or a leash tension meter.

Let start by breaking down ‘Bite proof’ into its most simple terms. The word proof was originally used in the sense of a test of something—such as a test of quality, worth, truth, etc. However, it is now often interpreted as meaning the same thing as evidence.

Bite is defined by the oxford dictionary as ‘to use your teeth to cut into or through something’

So – when we add bite and proof together, what do we really mean?

Do we mean to say that we have evidence? – if so, what evidence  or ‘proof’ is considered suitable? Something we will cover later in this blog.

For now lets focus on how we are going to define ‘bite’, despite the oxford dictionary definition, little research has investigated what people mean by “dog bite”, especially in light of frequently used language such as “nip” and “play bite” (Oxley et al, 2019)

The Ian Dumbar dog bite scale (2016) defines a level 1 bite as aggressive behaviour but no skin-contact by teeth, a level 2 bite is considered skin contact by teeth but no skin puncture. Ian Dumbar found that levels 1 and 2 compromise well over 99% of dog incidents. But if we can’t all universally agree on weather we feel that level 1 or 2 are even considered a bite, then how can we know what we mean when we are looking for a ‘bite proof’ muzzle.

For example, Oxley et al (2019) found that there was conflict surrounding weather a dog making contact with just a persons clothing was considered a bite. Furthermore, 81% of people considered a dog bite to be the teeth making contact and resulting in bruising, with or without skin puncture.  That means 19% of people asked didn’t believe a dog had bitten, unless there is skin puncture.

Opinions also differed according to the perceived intent, for example if the bite occurred during play 45% of people felt that this would not be considered as a bite. And if a dog ‘did not intend’ (How do we know a dogs intent?) to bite a person, 41% agreed that this would not be considered a bite.

For some people, bites which occurred during play are not considered “real” bites, whereas others stated that it was a bite regardless of whether the dog was playing. Westgarth and Watkins (2015) found that some people even contradicted themselves during interviews, giving different definitions of a dog bite when speaking about different events.

While there is evidence that with increasing injury severity, there is increased consensus on what is considered a bite, definitions were more debateable where no injury occurred, or injuries were mild.

Therefore, ‘Bite proof’ is a term that’s open for interpretation, its subjective and means different things to different people based on past experiences, learning, perceived intent, context, size of the dog and so much more!

If we don’t have a clear, universal understanding of what is considered a bite. We cannot clearly state that a muzzle is or is not ‘bite proof’.


...and once you have your definition of what you consider bite proof, drop it in the blog post comments! 

Putting the proof in ‘bite proof’

Ok, now we have looked at the word bite, lets revisit the ‘proof’. As I mentioned, there is no standardised definition, or test that can be done to test ‘bite proof’-ness.

A handful of customers feeding back that their dog was unable to bite through a muzzle, is not a representative sample. A demonstration of how non-flexible a muzzle is, is not representative of a dog bite, or longevity over time. A muzzle being made of a specific material is not representative of all muzzles – there is more than just the muzzles material that make them strong (or weak), a muzzles weakest points are the joints, the more separate parts and pieces joined together, the more room for error.

 Tensile strength testing

A muzzle company could tensile strength test, which is something we have explored extensively, and the issues raised below are all issues raised by plastics professionals that have led us to believe that even if we were to tensile strength test, we would be unfairly misleading you and miss-representing muzzle strength to gain sales, something we don’t feel is ethical or moral.

Tensile strength testing will tell you the strength of the plastic (or metal), when stretched outwards or crushed from top to bottom - which may help you visualise how strong our plastic muzzles are! Which we agree, might make a flashy viral video and result in an increase in sales. But what it won’t tell you, is how that plastic holds under the force of a dog bite, which is what is important to you and to us. Because a dog bite is a pretty specific mechanism, without recreating a dogs mouth/jaws and putting it inside the muzzle, we wouldn’t be able to test how the front portion of the muzzle would withstand being pushed outwardly and clamped from the inside.

 Replicating a dog bite

We could make a mechanical dog jaw – again something we have discussed and explored extensively. However, there is still much research to be done exploring the bite force of different breeds and the multitude of factors that can impact bite force such as skull shape (Case 2013), Body weight (Ellis et al 2009), length of snout or even the task they have been bred for (Brassard et al 2020). Therefore, it would be nearly impossible to calculate what bite force to put the muzzle under and what breed that would represent.

Even if we could devise a strength test with a mechanical jaw that we felt was representative of a dog bite, we would have to perform that test on each one of our sizes, with a huge variety of different pressures and different sized mechanical jaws at a huge cost, that may still not represent a live bite. This also wouldn’t be able to account for muzzle fit, what if someone had a large breed in one of our muzzles that was slightly too small, or a smaller dog in a muzzle slightly too large.. how would fit impact the strength of the muzzle? Something we can’t simulate with a mechanical jaw.

We have also considered using real dogs, trained for bite work. Again, this would make an excellent viral video for social media and would atleast show that the muzzle could withstand a bite, from those individuals, in that context! However, would that be representative of a ‘normal’ dog in a situation where they felt their life was under threat? We don’t know. There is no research exploring bite force of dogs in ‘live’ bite situations, because its unethical to put dogs under real threat.

However, what we do know that muscle volume impacts strength (Haxton, 1944) and exercise and training can improve jaw muscle function (Shirai et al, 2018) so it might be expected that the dogs trained for bite work have more powerful jaws? But what about health or age, there are simply to many variables to be able to achieve a realistic, representative sample, particularly because the number of dogs that would be comfortable with this exercise is already limited.

Furthermore, this process would have to be repeated every time we released a new size, because the strength differs on muzzle size alone, and then consider the variety of breeds that fit within that muzzles size, accounting for gender, fitness, age you would be asking a huge number of dogs to attempt to bite through a muzzle – which may it itself have ethical implications.

So in conclusion, no muzzle company has the ‘proof’ part of ‘bite proof’ which means claims are based on little to no evidence and not representative of the wider population. Therefore using the term ‘bite proof’ is a sales tactic, designed to draw in and convince customers to purchase on the basis of little to no evidence. Which is why we do not subscribe.

From the research we have done, we are the first and only muzzle company to explore and explain the complexities of a potential ‘bite proof’ claim. This post also doesn’t dive into the legal implications, of which there are many!

How muzzle use and maintenance impacts ‘Bite proof’-ness

OK so perhaps you have an understanding of the concerns around ‘Bite proof’, but what about other factors you might not have considered.

Think of a muzzle that you may have considered to be ‘bite proof’ and ask yourself

  • If I consider this muzzle to be ‘bite proof’ now, is this muzzle still ‘bite proof’ in one years time? Three years time?

How can we know...? Every dog’s experience whilst wearing a muzzle is likely to be wildly different. One dog might wear a muzzle during dog interactions including frequent, repetitive muzzle punches, one might avoid dogs all together. One dog might still attempt to pick up items, resulting in occasional muzzle smashes against the floor whilst another dog may never push their muzzle into the ground, even to sniff. One dog might have never attempted to bite through their muzzle, while another may have made multiple unsuccessful attempts – Is the muzzle that has had multiple attempted bites, muzzle punches, or ground smashes now compromised? Should we consider muzzles in the same way we do bike helmets? That once they have been damaged or undergone trauma, they need to be replaced in order to maintain ‘bite proof’-ness and therefore safety?



So even if a muzzle brand proclaims a muzzle is bite proof, what happens to that ‘bite proof’-ness over time? At what point is it no longer ‘bite proof’, and more importantly, does the muzzle brand define these parameters? Is it clear at what point your muzzle is no longer going to prevent a bite?

Further considerations besides muzzle use, include how the muzzle is maintained. We know that plastics and metals can be impacted by a variety of different things, such as temperature or the products used to clean and maintain them. If a muzzle is considered ‘bite proof’ at point of purchase, then what are the recommended guidelines provided by the company to maintain its structural integrity? Avoid certain temperatures? Wash in certain products? If these aren’t clearly outlined then over time the muzzle will loose ‘bite proof’-ness, which should be clearly explained to the customer to avoid someone having a serious incident by falsely believing that their muzzle will prevent a bite forever.

Another consideration is when muzzles are being modified, reshaped, bent or boiled. No muzzle company knows the impact that this has on the products strength. Its generally understood that when modifying a muzzle, the responsibility is no-longer with the manufacturer should the product then fail. But if brands that claim bite proof, are also suggesting you reshape or remodel, or a modification company has changed the model and resold on but still claim ‘bite-proof’ then at the very least the implications of doing such on the products integrity should be clearly stated.

Further more, what about the fastenings? The muzzle itself might remain strong over time, but what about the strapping – leather can wear and tear, some cheap rivets can rust or decay, metal fastenings can be compromised by sand or salt water. Weakened hardware or strapping will impact the muzzles ability to withstand a bite scenario, so at what point are any of these components no longer considered appropriate to prevent a bite?


And finally, there is always going to be the possibility that in an emergency, a dog is able to get their muzzle off, or an element breaks or fails. We wouldn’t call a bike helmet ‘brain injury proof’ because things can still go wrong. Injury depends on the circumstances with a wide range of variables impacting the likelihood of a brain injury.  

We should never be relying solely on a muzzle to prevent a bite. A muzzle is one of many forms of management, and should be used alongside other forms such as a lead, awareness gear, baby gates, consent based handling or by simply advocating for our dogs space.

Emergencies happen and there are muzzles that are appropriate for higher risk dogs that may be considered more likely to prevent serious injury and we will have a follow up blog post discussing them. 


In conclusion, here at The Muzzle Movement, we don’t believe muzzles can be responsibly described as ‘bite proof’. Our muzzles are designed to be strong, sturdy, and secure, our hardware and baskets are warrantied for life, and our muzzles have prevented dog bites. But that still does not meet what we believe to be the minimum standard of evidence to be able to say our muzzles are (or aren’t!) ‘bite proof’.



We are interested in your thoughts! So let us know in the comments!



Brassard, C., Merlin, M., Guintard, C., Monchâtre-Leroy, E., Barrat, J., Bausmayer, N., Bausmayer, S., Bausmayer, A., Beyer, M., Varlet, A. and Houssin, C., 2020. Bite force and its relationship to jaw shape in domestic dogs. Journal of Experimental Biology223(16), p.jeb224352.

Case L. P. (2013)The Dog: Its Behavior, Nutrition, and Health John Wiley & Sons

Dunbar, I., 2016. Dr. Ian Dunbar's Dog Bite Scale (Official Authorized Version).

Ellis, J.L., Thomason, J., Kebreab, E., Zubair, K. and France, J., 2009. Cranial dimensions and forces of biting in the domestic dog. Journal of Anatomy214(3), pp.362-373.

Haxton, H.A., 1944. Absolute muscle force in the ankle flexors of man. The Journal of physiology103(3), p.267.

Oxley, J.A., Christley, R. and Westgarth, C., 2019. What is a dog bite? Perceptions of UK dog bite victims. Journal of Veterinary Behavior29, pp.40-44.

Shirai, M., Kawai, N., Hichijo, N., Watanabe, M., Mori, H., Mitsui, S.N., Yasue, A. and Tanaka, E., 2018. Effects of gum chewing exercise on maximum bite force according to facial morphology. Clinical and Experimental Dental Research4(2), pp.48-51.

Westgarth, C. and Watkins, F., 2015. A qualitative investigation of the perceptions of female dog-bite victims and implications for the prevention of dog bites. Journal of Veterinary Behavior10(6), pp.479-488.


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