Generally speaking, lost pet disputes arise when a pet wanders away from home and is killed, injured, or adopted. The original owner of the pet wants it back or wants compensation for injury. The person who found or adopted the pet thinks their conduct was justified and they do not owe anything to the original owner. The law arbitrates such disputes and the outcome will depend on the state, the parties involved, and the particular facts of the case.
In one type of dispute, someone takes care of a lost pet and refuses to give it up when the owner discovers its whereabouts. The adopter and owner will go to court to find out who has a legal right to possess the pet. If the pet was adopted from an animal shelter, the adopter will probably have a right to possession because virtually all jurisdictions have impoundment laws that authorize such adoptions thereby extinguishing the original owner’s rights. If the adopter found the lost pet and started taking care of it, then the right to possess the pet will depend on the amount of time that has passed, whether the adopter made reasonable efforts to find the original owner, and whether the original owner acted in a blameworthy manner by abandoning the pet or failing to look for it. The amount of time that must pass in most states before the adopter becomes the true owner of the pet is usually measured in years if the pet is not adopted from a shelter and if the original owner did not act in a blameworthy manner.
Another type of dispute is one where a party kills or injures a lost pet and the original owner sues for money damages. Perhaps an annoyed neighbor traps a stray cat or a Good Samaritan brings a sick puppy to a veterinarian who euthanizes it. The general rule is that the finder of a lost pet is liable for unreasonable conduct that causes harm (negligence). Whether conduct was unreasonable will of course depend on the what a normal person would do in similar circumstances. Oftentimes, states will pass laws that modify this general rule. For example, most local governments have laws authorizing the capture, detention, and disposal of stray pets by means of adoption, euthanasia, or sale. Many states also have special rules that offer some protection for Good Samaritans and veterinarians that take care of lost pets.
The final type of dispute worthy of discussion involves the relationship between the adopter of a lost pet and third parties. When someone adopts a stray animal off the street instead of from a shelter their legal rights and duties are somewhat unclear. Although they may not acquire superior ownership rights against the original owner for months or years, they quickly acquire ownership rights and duties against third parties. A finder who intends to take care of a lost pet and in fact does so acquires a superior right to possession against everyone except the original owner and can generally sue in court if somebody wrongfully harms the pet. This determination is made by looking at the circumstances such as whether the finder fed or harbored it as well as the length of time he or she took care of the pet. The other side to acquiring some ownership rights is that the finder who adopts a lost pet also acquires a duty to keep other people safe from it. This is especially important to keep in mind when the lost pet is a dog because owners and keepers of a dog are often strictly liable for the damage it causes even if the owner acted reasonably.