It’s been my experience that many dog owners who have either dog or human aggressive dogs tend to underestimate their dog’s potential to hurt other dogs or humans. In addition to possible injury, there are also both civil and even criminal legal issues to consider.

It only takes a fraction of a second for a dog to inflict serious injury with a bite. Even after years of working with aggressive dogs, I am still amazed how fast they can bite.

When I broach the subject of muzzles with dog owners, I frequently hear something like the following, “I don’t want to do that to my dog; it will make him feel bad. Plus, other than when he is biting, he is a great dog.”

Dogs see muzzles as neutral things when they are properly acclimated to them. Does your dog obsess about his collar? Probably not. If dogs are properly habituated to a muzzle they will think of it in the same way as a collar – which is to say they won’t think of it.

And while it takes a dog only tenths of a second to bite, we have to hyper-focus our management efforts on those tenths of seconds. Dogs with a potential to bite need to wear a muzzle 100% of the time when they are in situations where they might bite.

Which dogs are the best candidates for muzzles? There are three primary variables I look at when it comes to making a muzzle decision.

The size of the dog is extremely important. While a 12-pound dog can cause serious injury (e.g., bite to a face), it’s nothing compared to the damage a 60+ pound dog can do.
It’s more important to muzzle dogs that are human aggressive (versus dog aggressive). Dogs normally do less damage to other dogs and the liability issues for a human bite can be substantial. It’s also normally not as difficult to manage and prevent dogs from biting other dogs.
Dogs that are unpredictable biters are always a big concern because we don’t know what is going to trigger a bite. Since it’s impossible to be on-guard 100% of the time, muzzles are a necessary insurance policy.

In short, a large dog that bites humans unpredictably is an easy decision when it comes to whether he should be fitted with a muzzle.

Muzzles provide the following benefits:

When people see a dog with a muzzle on, they normally steer clear. This is a benefit because these dogs are normally very uncomfortable with approaching humans or dogs on leash.
When used properly, muzzles have a calming effect on dogs.
They obviously protect people and/or dogs from bites; although they are not foolproof.
Muzzles not only calm the dog in many cases, but they can relax the owner since the bite risk is reduced. This has a positive feedback effect between handler and dog.

Dog owners need to be careful that they don’t push their dog into situations they would otherwise avoid if their dog weren’t wearing a muzzle. The motivation for aggressive behavior doesn’t change just because a dog has a muzzle on. Pushing a dog too far just because he has a muzzle on can make behavior issues worse.

I always recommend a basket muzzle versus a groomer’s muzzle. Basket muzzles look like the one at the top of this article. Good ones allow the dog to pant, drink and even take treats. They can be left on for long periods too. Groomer’s muzzles (pictured below) are good when short periods of muzzling are required. However, they don’t allow the dog to pant or drink which can be problematic after a short period. They also don't provide as much protection as a basket muzzle.

If you have a dog that is exhibiting aggressive behavior or has bitten another dog or human, please see a certified dog behavior consultant.