From a purely legal perspective, a pet might be injured intentionally, recklessly, negligently, or for a justifiable reason. If a pet is injured or killed in a manner that cannot be justified legally, the pet owner (the plaintiff) may be able to successfully sue the person who is responsible (the defendant). This article discusses when a defendant is and is not liable for damages, and the type of damages a plaintiff can recover in personal injury cases involving harm to a pet or other animal.
However callous it might seem, a pet is considered a plaintiff's "property" under the law in most states. As with other property, a plaintiff can recover damages from a defendant who causes injury to the pet/property.
An injury intentionally caused will create a fairly straight-forward lawsuit unless the defendant has a viable justification for his or her intentional acts, like self-defense or defense of others.
If the defendant injured or killed the plaintiff's pet on purpose, and the plaintiff has strong evidence proving the defendant's deliberate acts, then some form of liability is likely.
A defendant can also be found liable for an injury to the plaintiff's pet if he or she caused the injury while behaving recklessly. Generally, a reckless act is one that the defendant knows or should know is likely to result in a particular kind of harm (here, injury to a pet), but goes through with the act anyway. Note that the defendant is not required to want the harm to occur. For example, someone driving at twice the posted speed limit in a residential neighborhood could be found liable for recklessly injuring a dog.
A defendant can also be found liable if he negligently injures the plaintiff's pet. Negligent acts are different from intentional or reckless acts because a negligent defendant wasn't necessarily aware that his acts would lead to harm, he simply wasn't as careful as he should have been under the circumstances.
As already mentioned, pets are legally considered property. When property is negligently harmed or destroyed, the plaintiff is only entitled to compensation for the market value of the property or the costs of repairs. So, in the case of a pet, if the defendant's acts were no more than negligent, the plaintiff cannot recover for subjective damages like emotional pain and suffering, mental anguish and loss of quality of life. The plaintiff can recover for the value of the pet, with considerations like training and pedigree factored in and/or veterinary costs if the pet survives but requires medical treatment.
However, if the defendant's acts were intentional or reckless, the plaintiff might be allowed to recover emotional pain and suffering type damages under an infliction of emotional distress legal theory. Although the exact legal rules are complex and vary from state to state, in essence if a defendant knows that what he is about to do will hurt or kill the plaintiff's pet, he is intentionally causing the plaintiff emotional pain. Under those circumstances, the fact that the pet is only considered property does not matter. Keep in mind that intentional or reckless acts can also pave the way for punitive damages in some cases.
Note that a few states also allow damages for negligent infliction of emotional distress. Generally, however, the defendant's acts must be very negligent (or "grossly negligent" in legalese) for the plaintiff to be able to recover emotional distress damages. This means that an ordinary act of negligence, like not checking before backing up a car, will probably not allow a plaintiff to recover anything other than the market value of their pet.
For example, in a New York case, a plaintiff was not allowed to recover for negligent infliction of emotional distress when his dog died while being transported on an airplane -- despite the fact the plaintiff needed psychological counseling after losing his pet.
Most states have animal cruelty laws. If the local prosecutor successfully convicts a defendant of animal cruelty, the pet's owner is often entitled to recover some form of compensation from the defendant. If someone has intentionally harmed your pet, consider pressing criminal charges. A criminal conviction can sometimes be used as evidence of liability in a civil case. On the down side, criminal charges can put your civil case on hold until the criminal case is resolved.