Under the rule of capture established in Pierson v. Post, a wild animal becomes your legal property only when you physically capture it, kill it, or mortally wound it so that escape is effectively impossible. Chasing an animal — no matter how long, how hard, or how close you get — gives you no ownership right the law will protect. The 1805 New York decision drew a bright line at physical possession, and that line still governs how American law handles resources that move freely and belong to no one until someone reduces them to control.
The Fox Hunt Behind the Rule
The dispute happened on unoccupied land in Queens County, New York. Lodowick Post was hunting a fox with his hounds, running the animal across open ground and clearly intending to take it once his dogs closed the distance. Jesse Pierson, who saw the hunt in progress and knew Post was pursuing the fox, stepped in, killed the animal, and carried it off.1New York State Unified Court System. Pierson v Post
Post sued in a local justice’s court and won. Pierson appealed to the New York Supreme Court of Judicature, which took up a narrow question: does actively pursuing a wild animal with hounds give the hunter a property right the law will enforce against someone who makes the actual kill?1New York State Unified Court System. Pierson v Post
What the Court Held
Justice Daniel Tompkins, writing for the majority, reversed the trial court and ruled in Pierson’s favor. Pursuit alone creates no property right. To own a wild animal, a hunter must do one of three things: kill it, wound it so severely that escape is no longer realistically possible, or physically trap it. Short of that, the animal remains unowned and available to anyone else who takes it.1New York State Unified Court System. Pierson v Post
The court was open about why it drew the line so strictly. If mere pursuit conferred rights, courts would be swamped with arguments over how close a hunter had to get, how long the chase had to last, and how strong the intent had to be. Tompkins called such a rule “a fertile source of quarrels and litigation.” A rule that turns on physical possession is easy to apply and keeps disputes rare.2Justia. Pierson v Post
Post had never touched the fox. Under the rule the court announced, that was the end of his claim.
The Dissent That Made the Rule Famous
Justice Brockholst Livingston disagreed, and his dissent is taught alongside the majority because it lays out the competing intuition head-on. Livingston would have protected any hunter who had a “reasonable prospect” of capturing the animal. His argument was practical: foxes were harmful to farmers, hunting them served the public, and no one would bother with the effort if a bystander could snatch the prize at the last second.2Justia. Pierson v Post
Where the majority chose certainty, Livingston chose labor. Rewarding effort discourages free-riding, but it invites exactly the boundary disputes the majority wanted to prevent. That trade-off — a clear rule versus a fair standard — is why the case has stayed in the casebooks. The majority won, and the rule of capture is the majority’s rule.1New York State Unified Court System. Pierson v Post
How the Rule Works for Wild Animals
The fox in Pierson v. Post was an animal ferae naturae — a creature of wild nature. Both sides agreed on that classification, and it does most of the work in the case. Domesticated animals belong to someone from birth or purchase. Wild animals belong to no one while free, and become property only through capture.1New York State Unified Court System. Pierson v Post
That ownership is qualified, not absolute. It lasts only as long as control lasts. If a captured wild animal escapes back into the wild, the property right disappears with it. A neighbor who kills your escaped rabbit the moment it crosses into the forest owns the rabbit; you do not.
Animals with a Habit of Returning
There is one recognized exception. Under the doctrine of animus revertendi, if a captured wild animal has developed a habit of returning to its owner — trained falcons and homing pigeons are the classic examples — the property right survives temporary absences. The animal’s demonstrated pattern of coming back sets it apart from a truly wild creature that has simply regained its freedom.
Traps, Nets, and Constructive Possession
Physical contact is not the only way to capture. When an animal is caught in a trap or net, the law treats the trapper as being in “constructive possession,” even if no one is present at the moment of capture. What matters is whether escape has become effectively impossible. A fish caught in a holding net with no realistic way out has been captured; a school of fish surrounded by a net that still has a meaningful gap has not. Near-certainty of capture counts. Almost-there does not.
Where the Rule of Capture Reaches Beyond Animals
The reason Pierson v. Post matters outside property casebooks is that courts extended its logic to any resource that moves freely across boundaries and belongs to no one until reduced to possession.
Oil and Gas
The rule of capture became the foundation of early American oil and gas law. Oil pumped from a well belongs to the surface owner who extracted it, even if the underground reservoir extends beneath a neighbor’s land. Because oil migrates toward whatever well taps it, the rule historically encouraged a race to drill: pump faster, get more, regardless of where the oil originally sat.
The predictable result was waste and overproduction. States responded with conservation regulations and with “unitization,” where owners above a shared reservoir operate it as a single unit and split proceeds proportionally. Courts have also recognized limits. A driller who uses artificial methods to drain a neighbor’s oil, or who directionally drills a well bottoming out under someone else’s land, cannot hide behind the rule.
Groundwater
Several states apply the same reasoning to groundwater, treating it like oil: whoever pumps it from beneath their land owns it. The approach gives investors certainty but can lead to over-extraction, which is why groundwater conservation districts, where they exist, regulate pumping to protect shared aquifers.
News and Quasi-Property
The U.S. Supreme Court applied capture-like reasoning to intangible property in International News Service v. Associated Press (1918). The Court held that freshly gathered news carried a “quasi-property” quality between competitors, so one news service could not copy another’s reporting and sell it as its own. The Court described the defendant as “endeavoring to reap where it has not sown” — the labor rationale Livingston lost with in 1805, showing up on the winning side more than a century later.3Justia. International News Service v Associated Press, 248 US 215 (1918)
Where Federal Law Overrides the Rule
The common law rule assumed wild animals were free for the taking. For many species, that assumption no longer holds. Physically capturing a federally protected animal does not give you ownership; it exposes you to prosecution.
The Endangered Species Act makes it unlawful to “take” any listed species, and the statute defines “take” broadly to include harassing, harming, pursuing, hunting, shooting, wounding, killing, trapping, or capturing. Violations can carry civil penalties and criminal charges. For listed species, the rule of capture does not apply at all — federal law has removed them from the pool of animals private citizens can claim.4Office of the Law Revision Counsel. 16 USC 1538 – Prohibited Acts
The Migratory Bird Treaty Act reaches further. It makes it a federal crime to pursue, hunt, take, capture, or kill any migratory bird, or to possess any part, nest, or egg, without a permit from the Department of the Interior. The Act covers roughly a thousand species protected under treaties with Canada, Mexico, Japan, and Russia. No amount of physical capture creates a lawful property right in these birds without federal authorization.5Office of the Law Revision Counsel. 16 USC 703 – Taking, Killing, or Possessing Migratory Birds Unlawful
In 1805, the only question was which hunter got credit for the kill. For a large and growing category of species, that question no longer arises, because the animal was never available to be captured in the first place. The rule of capture still decides who owns the fox. It no longer decides who owns the eagle.