Massachusetts Dog-Bite Laws

Learn how dog-bite lawsuits work in Massachusetts, when owners can face criminal liability, and how the state handles dangerous and nuisance dogs.

By , Attorney UC Berkeley School of Law
Updated 7/14/2023

Massachusetts imposes significant responsibilities on dog owners. State law makes owners "strictly liable" for most injuries and damage inflicted by their dogs, meaning it doesn't matter if the owner took precautions or if the dog had never misbehaved before. The state also has detailed rules about how cities and towns should deal with dogs that create nuisances or might be a danger to the public. Here's what you need to know if you're a dog owner or have questions about an incident involving a dog in Massachusetts.

Massachusetts Imposes "Strict Liability" on Dog Owners

Massachusetts, like most states, takes a "strict liability" approach to injuries and property damage caused by dogs.

Under Massachusetts General Law Chapter 140, Section 155, an owner can be held civilly liable even if they didn't know their dog might be dangerous, and even if they took precautions to protect people and property from their dog.

Strict liability contrasts with the so-called "one-bite rule" used by some states. Under that approach, an owner can be liable for a victim's injuries only if they had reason to know their dog might be dangerous.

Many states have one law that covers dog bites, and another for other injuries caused by dogs. In Massachusetts, though, the same strict liability law applies to bites, other injuries, and property damage.

So, suppose that someone is walking in a public park when a dog breaks free of its leash and jumps on her. She falls to the ground and, in the process, breaks her wrist and shatters the screen of her phone. Under Massachusetts law, the owner could be held legally responsible for the injury and property damage—even if the owner did everything he could to prevent the incident.

Liability When the Owner Isn't Present

Under Massachusetts's strict liability rule, an owner is legally responsible for their dog's behavior even when they aren't in control of—or even in the same location as—their pet. That means, for example, that the owner could face a lawsuit if their dog injures someone while it's being walked by a pet sitter or being taken care of by a friend.

But the state's strict liability law applies not only to a dog's owner, but also to its "keeper." A "keeper" is someone who doesn't necessarily own the dog, but has control and custody of it. The keeper could be a professional being paid by the owner, like a veterinarian or a dog walker, or just a friend or relative who has agreed to look after the animal.

Lawsuits where a "keeper" might be liable can be complicated for two reasons:

  • In some cases, a defendant might have a good argument that they didn't actually have enough control over the dog to qualify as its keeper.
  • Under Massachusetts law, a victim will usually have to choose whether to sue the owner or the keeper, but can't sue both.

If you have questions about issues like these, you could benefit from speaking with an attorney who can advise you based on the facts of your case.

Defenses for Owners in Dog-Bite Cases

Even under strict liability, Massachusetts doesn't hold owners responsible for injuries and property damage caused by their dog if, at the time of the incident, the victim was:

  • trespassing
  • committing another tort, or
  • "teasing, tormenting or abusing" the dog.

(Mass. Gen. Laws ch. 140, § 155.) Keep in mind that someone who is entitled to be on private property—for example, a mail carrier or an invited guest—is not trespassing.

Liability When Kids Are Involved

Massachusetts has special rules that apply to younger dog owners and younger victims:

  • Parents are responsible. If the dog's owner or keeper is a minor, then the minor's parents or guardians are legally responsible for damage and injuries caused by the dog.
  • Young children get special protection. Massachusetts law assumes that children under the age of seven are too young to be held responsible for trespassing or doing anything else that excuses owners for injuries inflicted by their dogs. It's an owner's burden to show why that assumption is wrong in a specific case.

(Mass. Gen. Laws ch. 140, § 155.)

Suing Under Massachusetts Negligence Rules

A dog-bite victim can bring a lawsuit under the strict liability rules described above. But victims can also bring injury claims over dog bites under Massachusetts's general rules for negligence.

A negligence lawsuit is harder to win than one brought under a strict liability standard, because plaintiffs in negligence cases have to show not only that they were harmed but also that the harm was caused by the defendant's carelessness.

This carelessness requirement means that it normally wouldn't make sense for a victim who can bring a lawsuit based on strict liability to sue for negligence instead. But there are times when a negligence lawsuit could be the right option for a victim. That's because Massachusetts's strict liability statute specifies that it covers a dog's "owners or keepers."

Take a situation where an owner lets their large dog roam freely through an apartment complex, ignoring the building's rules against letting dogs off-leash in common areas. Residents complain repeatedly, but the building's owners take no action. If the dog knocks someone down and injures them, the victim might have:

  • a case against the dog's owner under strict liability, and
  • a case against the building owners for negligence, based on their failure to take reasonable steps to protect residents from the rule-breaking dog owner.

Negligence can also come into play when the victim is an animal worker like a veterinarian. As we discussed earlier, under Massachusetts law an animal provider temporarily becomes the dog's "keeper" while it's in their custody. Since they're temporarily responsible for the animal's behavior, they can't bring a strict liability lawsuit against the owner if the dog hurts them.

But a vet or kennel worker could still sue for negligence—arguing, for example, that the owners knew their dog was unusually dangerous and should have warned anyone who'd have to handle the animal. (Remember that if the victim is a third party—like someone in the business' waiting room—they could have a strict liability claim against either the dog's owner or the "keeper" who was temporarily responsible for the animal.)

Damages in Massachusetts Dog-Bite Cases

If you sue a dog owner or handler, your lawsuit will follow the same process as other personal injury lawsuits in Massachusetts. The rules for damages are mostly the same, too—if an owner is found liable for your injuries or damaged property, they (or their insurance) are required to pay you compensation.

But Massachusetts also has a damages law designed to penalize owners of dangerous dogs who fail to control their pets. This law applies to owners of dogs that have been deemed dangerous and then go on to either:

  • wound a person, or
  • wound, harass, or kill livestock or fowl.

In these kinds of cases, the dog owner is liable for three times the amount of damages they'd normally owe the plaintiff. If, for instance, a jury decides that an injured person is owed $5,000 to cover their medical expenses and other damages, that award would automatically increase to $15,000.

The Statute of Limitations for Dog-Bite Lawsuits in Massachusetts

Massachusetts, like all states, sets deadlines that require plaintiffs to file civil lawsuits within a certain period of time. The Massachusetts statute of limitations for personal injury claims is three years. That means you have three years to file a negligence or strict liability lawsuit if someone's dog has injured you or damaged your property.

Massachusetts's Rules for Dangerous and Nuisance Dogs

Local governments in Massachusetts can deem a dog a "dangerous dog" or a "nuisance dog" based on its behavior.

In very serious cases, dangerous dogs can be taken from their owners and euthanized. It's much more common, though, for local governments to order owners of dangerous dogs and nuisance dogs to take steps that protect the public from dangers or disruptions caused by their animals. The consequences of disobeying these orders can be serious both for owners and their dogs.

What Is a "Dangerous Dog" in Massachusetts?

"Dangerous" dogs, as the name implies, are in a more serious category than nuisance dogs. In Massachusetts, a "dangerous dog" is a canine that has:

  • injured or killed a person or domestic animal, or
  • behaved in a way that makes it reasonable to assume that it might injure or kill a person or domestic animal.

Massachusetts law prohibits municipalities from deeming a dog dangerous—or imposing any special regulations on any dog—just because of its breed. Dogs also can't be deemed dangerous just because of their growling or barking.

Additionally, Massachusetts recognizes that there are times when it might be reasonable for a dog to threaten or attack a person or animal. As long as the dog's behavior isn't "grossly disproportionate" under the circumstances, it can't be deemed dangerous for an attack or threatening behavior if:

  • it was protecting or defending itself, another domestic animal, or a person from attack or assault
  • the person who was attacked or threatened by the dog was committing a crime against the person or property of the dog's owner or keeper
  • the person who was attacked or threatened was "teasing, tormenting, battering, assaulting, injuring or otherwise provoking the dog," or
  • the dog attacks or threatens a person or animal that has entered its enclosure (for example, a fenced-in yard) without the owner's permission.

Like the state's strict liability rules, its rules for dangerous dogs treat children under age seven differently. There's a presumption (which a dog owner can rebut with evidence) that a very young child couldn't have been committing a crime, provoking a dog, or trespassing. (Mass. Gen. Laws ch. 140, § 157(a)(4).)

What Is a "Nuisance Dog" in Massachusetts?

According to Massachusetts law, a "nuisance dog" is a canine that:

  • annoys a sick person who resides in the vicinity with excessive barking or another disturbance
  • disrupts people's "quiet and peaceful enjoyment" with excessive barking, damage, or other interference, or
  • has threatened or attacked a person, a domestic animal, or livestock, but not in a way that was "a grossly disproportionate reaction" under the circumstances.

Determining That a Dog is a "Dangerous Dog" or a "Nuisance Dog"

Under Massachusetts General Law Chapter 140, Section 157, anyone can make a written complaint to their local government if they think a dog owned or kept in their town is dangerous or a nuisance. The complaint should be made to the "hearing authority," which is the local government official or police officer in charge of handling dog complaints.

The hearing authority will then investigate to decide if the dog really is a nuisance dog or a dangerous dog. That investigation includes a public hearing where the person who made the complaint is questioned under oath.

If the complaint accused the dog of being a nuisance dog, the hearing authority can either:

  • dismiss the complaint, or
  • deem the dog a nuisance dog.

If the complaint accused the dog of being a dangerous dog, the hearing authority can:

  • dismiss the complaint
  • deem the dog a dangerous dog, or
  • deem the dog a nuisance dog.

The Consequences When a Dog is Deemed "Dangerous" or a "Nuisance"

If a dog is deemed a nuisance dog, the hearing authority can order the owner to take steps to address the causes of the dog's behavior.

If a dog is deemed a dangerous dog, the hearing authority must issue at least one order from a list laid out in Massachusetts law. The possible orders are that:

  • the dog be "humanely restrained"
  • the dog be confined to the premises of its owner or keeper
  • the dog wear a muzzle and be kept on a strong leash when it's off its keeper's property
  • the owner or keeper obtain (or show that they made a reasonable effort to obtain) a $100,000 insurance policy to cover any damage or injuries inflicted by the dog
  • the owner or keeper provide the authorities with information (like photographs, veterinary records, or microchip information) that can be used to identify the dog
  • the owner or keeper have the dog spayed or neutered, or
  • the dog be humanely euthanized.

Under Massachusetts law, these orders have to be carried out humanely. For example, there are requirements for how a dog can be confined, and a dog can't be spayed or neutered if a veterinarian thinks it has a medical condition that makes the procedure inappropriate. (Gen. Laws ch. 140, § 157(c).)

When Owners Disagree With a Decision About Their Dog

An owner who disagrees with the hearing authority's decision has 10 days to contest it by filing a petition in state court. A court official called a magistrate will review the hearing authority's order and listen to the same witnesses who testified at the original hearing. A magistrate can only overturn a hearing authority's decision if they think it was made in bad faith or without proper cause.

There is also a final level of review available to an owner who disagree with the magistrate's decision. The owner can file an appeal asking a judge to review the case. The judge has more leeway than the magistrate to make their own decision about the dog, regardless of what the hearing authority originally decided. The judge can agree with the owner and dismiss the case, or decide to deem the animal a nuisance dog or dangerous dog.

Once a judge makes a decision, it's final. The owner can't appeal, and neither can the town nor the person who originally made the complaint.

When an Owner Disobeys a Government Order About Their Dog

Owners who don't comply with orders about their dogs risk serious consequences both for themselves and for their pets.

Owners can be punished with a fine of up to $500 and up to 60 days in jail. For a second offense, the penalty could be a $1,000 fine and 90 days in jail.

If a judge thinks there's probable cause (in other words, a good reason) to believe that an owner isn't complying with an order about their dog, they can issue any additional order they think is necessary to protect other animals or the public. These orders can include that the dog be restrained, confined, or impounded. The government can also permanently take away the animal, and ban the owner from licensing a dog in Massachusetts for five years.

Criminal Charges in Massachusetts Dog-Bite Cases

In addition to the civil penalties we've discussed above, it's possible for a dog owner to be charged with a crime under the state's general criminal laws if they order their dog to attack another person.

For example, in a 2005 case, a jury found a man guilty of ordering his dog to bite a woman's hand after an argument. The man was convicted of assault and battery with a dangerous weapon. An appeals court later confirmed that, given the evidence, it was reasonable to say that the man had used his dog as a dangerous weapon.

More About Dog Bites and Animal Law

Whether you own a dog or have concerns about one in your neighborhood, it's important to know how local law applies to your situation. Remember that, in addition to the requirements of Massachusetts state law, each town and city can make its own rules covering dog licensing and animal control. Your best bet is to look up your town's regulations online—Boston, for example, has a website with information for pet owners in the city.

It may be helpful to speak to a lawyer if you have specific questions about your situation. As we've seen, incidents involving dogs can raise questions involving personal injury law, animal law, and even criminal law—so it's important to seek out an attorney with the right experience for your case.

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