Strict Liability: Animals and Abnormally Dangerous Activities

Liability for Animals

Strict liability imposes responsibility without regard to fault — the defendant is liable even though she exercised the utmost care. It applies in three principal areas: animals, abnormally dangerous activities, and products (covered separately). For each, the rationale is that the defendant has introduced an extraordinary risk and should bear its costs.

Wild animals (ferae naturae): An owner or possessor of a wild animal (lions, bears, wolves, venomous snakes, monkeys) is strictly liable for harm caused by the animal's dangerous propensities characteristic of its kind, even if the owner took every precaution. The liability covers harm from the animal's natural dangerous tendencies — a pet tiger that mauls, a venomous snake that bites. Strict liability generally protects licensees and invitees but not trespassers (a trespasser injured by a watchdog or wild animal usually must prove negligence).

Domestic animals: The owner of a domestic animal (dogs, cats, livestock, horses) is not strictly liable unless she knew or had reason to know of the animal's dangerous propensities abnormal to its class. This is the common-law 'one-bite rule': liability attaches once the owner is on notice (e.g., the dog has bitten or shown vicious tendencies before). A separate strict-liability rule governs trespassing livestock that damage property.

California's dog-bite statute (Civ. Code § 3342) modifies the common law: a dog owner is strictly liable for damages suffered by any person bitten while in a public place or lawfully on private property, regardless of the dog's former viciousness or the owner's knowledge. The one-bite rule is thus displaced for bites in California — but only for bites; injuries from a dog knocking someone over (non-bite) still fall under common-law negligence or the knowledge-based rule.

Abnormally Dangerous (Ultrahazardous) Activities

A defendant who carries on an abnormally dangerous activity is strictly liable for resulting harm. The Restatement (Second) § 520 lists six factors; the Restatement (Third) distills them to two essentials. The activity is abnormally dangerous if:

1. It creates a foreseeable and highly significant risk of physical harm even when reasonable care is exercised by all actors; AND
2. The activity is not one of common usage in the community.

The fuller six-factor test (Restatement Second) weighs: (a) existence of a high degree of risk; (b) likelihood the harm will be great; (c) inability to eliminate the risk by reasonable care; (d) extent the activity is not a matter of common usage; (e) inappropriateness of the activity to the place where it is carried on; and (f) the value to the community weighed against its dangerous attributes.

Classic ultrahazardous activities: blasting/explosives, storing large quantities of toxic chemicals or flammables, fumigation, crop dusting, transporting hazardous materials, and harboring radioactive materials. By contrast, activities of common usage — driving a car, operating a gas utility line — are generally judged under negligence, not strict liability. The originating English case is Rylands v. Fletcher (strict liability for the escape of a 'non-natural' thing brought onto land, such as a reservoir that floods a neighbor's mine).

Scope of Strict Liability and Defenses

Strict liability is not boundless. Two limiting principles recur on the bar:

(1) Harm must flow from the dangerous propensity. The defendant is liable only for the kind of harm that makes the activity (or animal) abnormally dangerous. If blasting operations cause harm only because a startled animal bolts and tramples a bystander in a way unconnected to the explosion's force, or if the harm results from a freak cause outside the characteristic risk, strict liability may not attach.

The famous illustration: a truck transporting dynamite that injures a pedestrian by an ordinary collision (rather than an explosion) is governed by negligence — the harm did not result from the dangerous propensity (explosiveness) that justifies strict liability.

(2) Proximate-cause and intervening-force limits still apply. An unforeseeable intervening cause can cut off even strict liability.

Defenses:

• Comparative fault: In California (a pure comparative-fault jurisdiction), a plaintiff's negligence reduces recovery in strict-liability actions; the old rule that ordinary contributory negligence was no defense to strict liability has given way to comparative apportionment in most jurisdictions.
• Assumption of risk: A plaintiff who knowingly and voluntarily encounters the danger (e.g., a person who deliberately provokes a known-wild animal) may be barred or have recovery reduced.
• Trespassers: Generally cannot recover in strict liability for animal injuries; they must prove negligence (except where the landowner uses a vicious watchdog as a deadly trap).

Essay hypothetical: A demolition company uses dynamite to raze a building. The blast's concussion shatters windows in a neighboring home, and flying debris injures a passerby. Both harms flow directly from the explosive force — the characteristic danger of blasting — so the company is strictly liable regardless of how careful it was. If, instead, a worker negligently dropped a tool that injured the passerby, that harm would be analyzed under negligence, not strict liability, because it did not arise from the abnormally dangerous propensity of the activity.