Dog Bites and Other Injuries: A Dog Owner's Legal Defenses

When a dog hurts someone, its owner might be able to avoid legal responsibility based on the victim’s actions.

By , J.D. UC Berkeley School of Law
Updated by David Goguen, J.D. University of San Francisco School of Law
Updated 9/30/2022

Dog owners are usually legally responsible when their pets bite people or hurt them another way (such as by knocking them over). That means an injured person may file an insurance claim or sue the animal's owner to seek compensation for dog-bite-related harm, including medical expenses.

But the animal owner's liability could be reduced or eliminated altogether if the person making the claim:

  • provoked the dog
  • was trespassing or breaking the law at the time of the injury
  • voluntarily risked getting hurt by the dog
  • can't show that they were actually bitten, or
  • contributed to the injury by being unreasonably careless.

Dog-Bite Injury Claims and Owner Liability

Before we dive into possible defenses to a dog-bite claim, let's explain that an injured person may generally sue a dog owner based on one (or more) of the basic rules for dog-bite injuries:

  • a legal principle known as the "one-bite rule" that makes owners liable if they knew their dogs posed a danger
  • "strict liability" dog-bite laws in most states that make owners responsible even if they didn't know the dog could be dangerous, and
  • laws or court decisions that make negligent dog owners liable if they were unreasonably careless in controlling their animals.

The dog-bite laws in many states don't apply in certain circumstances—most commonly, when the injured person provoked the dog or was trespassing. Some of these statutes make the person who was bitten prove that they weren't at fault (rather than showing that the animal owner was to blame). And some defenses may be available if the owner's liability is based on the one-bite rule or negligence, but not under a dog-bite statute.

Was the Dog Provoked?

Dog owners will almost surely be off the hook if the injured person clearly provoked the animal—for example, by hitting or teasing it. But what about other actions that aren't so obviously provocative? Depending on the circumstances, courts might relieve owners of liability when victims unintentionally provoke dogs by:

  • accidentally stepping on their tails (see Brans v. Extrom, 701 N.W.2d 163 (Mich. Ct. App. 2005))
  • petting strange animals when they're eating or chained up
  • intervening in a dog fight, or
  • spraying repellant on a dog in self-defense (see Steichman v. Hurst, 275 N.E.2d . 679 (Ill. App. 2d 1971)).

Toddlers are prone to hugging strange dogs, patting them hard, or playfully pulling on their tails. If the dog responds by biting the child, can the animal's owner use the provocation defense? The answer partly depends on the wording of the relevant state law and how the courts interpret it. For instance, in Massachusetts and Connecticut, the dog-bite statutes presume that an injured child younger than seven didn't provoke the dog, which means that the owner would have to prove there was provocation (Mass. Gen. Laws, ch. 140, § 155; Conn. Gen. Stat. § 22-357). Courts in some states have ruled that the provocation exception in a dog-bite statute applies even when the victim was very young (see, for example, Reed v. Bowen, 503 So.2d 1265 (Fla. App. 1986) and Toney v. Bouthillier, 631 P.2d 557 (Ariz. App. 1981)). Other courts have found that this defense doesn't apply to three-year old children, because they aren't responsible for their actions or aren't capable of provoking a dog (see Ramsey v. King, 470 N.E.2d 241 (Ohio Ct. App. 1984)) and Smith v. Sapienza, 115 A.D.2d 723 (N.Y. App. Div. 1985)).

Did the Injured Person Know the Risk of Injury?

A dog owner might be able to avoid liability by proving that the injured person knew there was a risk of injury from the dog but voluntarily took that risk anyway. For instance, an owner might not be responsible if the victim ignored a prominent "Beware of Dog" sign (Benton v. Aquarium, Inc., 489 A.2d 549 (Md. App. 1985)) or agreed to take care of the dog (Murphy v. Buonato, 696 A.2d 320 (Conn. 1997)).

This rule usually applies when dogs hurt veterinarians and other people who work with animals—like vets' assistants, groomers, pet sitters, and kennel operators—because they take the risk of dog bites and other injuries as part of the job. However, courts don't all agree whether dog owners can use the assumption-of-risk defense when they've been sued under a state's dog-bite law. Some courts have concluded that the defense isn't available when the statute doesn't include it as an exception to the owner's strict liability (see, for example, Collins v. Kenealy, 492 N.W.2d 679 (Iowa 1992)) and Pulley v. Malek, 495 N.E.2d 402 (Ohio 1986)). Other courts have taken the opposite position. In California, for instance, courts have long agreed that owners are relieved from strict liability under the law when injured people have voluntarily accepted the risk of getting hurt by an animal (Nelson v. Hall, 211 Cal. Rptr. 668 (Cal. App.1985)).

Did a Bite Actually Occur?

There are plenty of instances in which a dog might get agitated or become aggressive, and snap at or seemingly attempt to bite a person, but no actual contact is made between the animal's teeth and any part of the person's body.

A valid dog-bite insurance claim or lawsuit requires that the claimant (the person making the claim) or the plaintiff (the person filing the lawsuit) be able to show that they've suffered actual harm. Even if a dog demonstrates aggressive behavior in a certain situation and scares the wits out of someone, or makes every attempt to bite someone, unless a bite actually occurs the animal's owner might be able to escape liability—especially under a state law that bases a dog owner's liability on whether or not a bite occurred.

Was the Injured Person Trespassing?

Owners usually aren't liable when their dogs hurt trespassers. Here again, the rules vary depending on the state and the legal basis for the lawsuit:

  • Most of the states' dog-bite laws don't apply if the injured person was trespassing or wasn't "lawfully" on private property.
  • When the one-bite rule applies, it shouldn't matter whether the injured person was trespassing—in theory, at least. In practice, courts and juries are reluctant to hold dog owners liable to trespassers, even if the owners knew their dogs were dangerous.
  • Courts don't agree whether trespassers can successfully sue dog owners for negligence. In some states, the trespasser may win if the animal's owner acted unreasonably under the circumstances. Other states still use an old legal rule making landowners liable only if they intentionally hurt trespassers or didn't warn of danger even though they knew trespassers were on their land. But there's an important exception to this rule when it comes to children: Landowners generally have a duty to protect trespassing children, because they don't have the judgment to avoid dangerous situations (see DeRobertis v. Randazzo, 462 A.2d 1260 (N.J. 1983).)

The rules on what is and isn't trespassing can also be complicated. Basically, a trespasser is someone who wasn't invited on the property or doesn't have a good reason to be there. This could include sticking a hand through a fence to pet a dog (see Kenney v. Barna, 341 N.W.2d 901 (Neb. 1983)). But courts will usually find that you've given an "implied invitation" to members of the public to approach your door on common errands (like asking directions or taking surveys) unless you've warned them away with signs or locked gates. Also, mail carriers and police officers performing their official duties have a legal reason to be on private property.

Another general rule is that when it's reasonable to expect that people will come on your property—even if you didn't explicitly invite them—you'll probably be liable if your dog hurts them when they're there. This principle is particularly important when it comes to children, who are likely to wander onto neighbors' yards to play with dogs. Owners have a legal responsibility either to prevent children from coming on their property or to keep their dog from hurting the kids.

Was the Injured Person Breaking the Law?

In a few states (like Iowa and Maryland), the dog-bite statutes don't apply if the victims were committing a crime. But in Ohio, that crime must be something more than a "minor misdemeanor."

Was the Injured Person Careless?

States have different ways of dealing with the question of liability when dog-bite victims' own carelessness contributed to their injuries. In the majority of states that use some form of "comparative negligence" rule, the victims will receive less compensation in proportion to their share of the blame. But most of those states cut off all compensation when the injured person's share reaches 50 or 51 percent. And a few states deny any compensation to victims who contributed to their injuries, even the least bit. Depending on the state and how its courts interpret the law, comparative negligence may not apply when an injured person sues under a dog-bite statute rather than based on the owner's negligence. (For more details, see our article on when dog-bite victims are partly at fault.)

Speaking With a Lawyer

The rules on legal defenses for dog bites are complicated and can vary widely from state to state, as well as from one set of circumstances to the next.

If you're facing a lawsuit over an alleged injury caused by your dog, you should strongly consider speaking with a personal injury lawyer. An attorney experienced in this area can fully explain the defenses that are available in your situation and state, and can help protect your rights.

And if you've been hurt by someone else's dog and are thinking of suing the owner, a lawyer can help you prepare to counter any arguments that you were at least partly to blame. Learn more about getting help from a personal injury lawyer.

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