Last week, 43 monkeys, all of them young female rhesus macaques, escaped from the Alpha Genesis research laboratory in Yemassee, South Carolina, when an employee failed to properly secure the door to their enclosure.

It wasn’t the first time something like this happened at Alpha Genesis, a company that breeds and uses thousands of monkeys for biomedical testing and supplies nonhuman primate products and bio-research services to researchers worldwide. In 2018, the US Department of Agriculture (USDA) fined the facility $12,600 in part for other incidents in which monkeys had escaped. “We’re not strangers to seeing monkeys randomly,” a nearby resident and member of the Yemassee town council told the New York Times.

Alpha Genesis is now working to recapture the macaques, who are each about the size of a cat; over the weekend, 25 of them were recovered. Meanwhile, the animal protection group Stop Animal Exploitation Now, which for years has filed federal complaints against the facility, has called on the USDA to prosecute Alpha Genesis as a repeat violator of its duty to keep the animals secure.

“The recovery process is slow, but the team is committed to taking as much time as necessary to safely recover all remaining animals,” a Facebook post from the Yemassee Police Department said, attributing the comment to Alpha Genesis CEO Greg Westergaard.

In one way, this is a story about what looks like a corporate failure. But there is another way to understand this situation, both legally and morally. What if these intrepid macaques, who the lab has said pose no threat to the public and carry no infectious diseases, have a legal claim to freedom?

The legal status of wild animals is more contested and malleable than ever, from the recent court case arguing that Happy, an elephant living at the Bronx Zoo, was a legal person entitled to freedom to the phasing out of animal use at entertainment venues like circuses and the end of US lab experimentation on chimpanzees. While Alpha Genesis may have a strong financial incentive to recapture the escaped monkeys, longstanding legal doctrines suggest that the 18 monkeys who remain at large may not belong to the company as long as they remain free and outside of its custody. State officials, or perhaps even members of the public, might even be legally protected in rescuing these monkeys from a fate of cage confinement and invasive experimentation and bringing them to a sanctuary. Such an outcome would matter not just for these monkeys but also for the rights of captive animals more broadly.

When a captive animal becomes free

For many people, the idea of a lost animal becoming the property of another person might seem absurd. Certainly, no one would imagine forfeiting the companionship of a beloved dog or cat because the animal got out of the yard and was found by someone else. Neither law nor morality treats the escape of a domesticated animal as tantamount to a forfeiture of all claims to the animal.

But when it comes to wild animals, the law is different.

When a captive wild animal escapes, their captor generally remains liable for any damage the escaped animal creates to persons or property, but they may lose ownership of the animal, especially if the creature integrates into an existing wild population (sometimes called “reverting to the common stock”). That might sound unlikely for rhesus macaques in the US — the species is native to South and Southeast Asia and has been exported around the world for lab testing. But it turns out that it’s perfectly possible to live as a free-roaming rhesus macaque in South Carolina, where a more than four-decade-old population of the monkeys resides on the state’s Morgan Island, also known as “Monkey Island.”

Originally relocated from Puerto Rico between 1979 and 1980, the Morgan Island macaques now serve as a kind of reservoir of lab monkeys for the US government. Last year, Alpha Genesis won a federal contract to oversee the monkey colony there — in fact, the 43 escaped macaques had originally lived as “free-range” monkeys on the island before they were taken to be used for testing and research purposes, the US Centers for Disease Control and Prevention told CBS News in a statement. While these monkeys may not be able to rejoin the Morgan Island colony on their own, the fact that they came from a wild population strengthens the view of them as animals who not only can live in the wild but who deserve to be free.

Our modern understanding of animals’ legal status derives from 19th-century American common law cases, which adopted the classical Roman legal approach to wild animals, or ferae naturae. Under that system, wild animals were a special type of property known as “fugitive” property because they could move freely and weren’t owned by anyone before being captured by a human. This created unique legal challenges — for example, conflicts between two hunters claiming the same animal — that can help us understand the case of the escaped monkeys.

The 1805 New York Supreme Court case Pierson v. Post, sometimes considered the most famous property case in American law (and about which one of us has written a book), is the starting point for understanding who legally owns a wild animal. In a dispute between two hunters, one who had been in hot pursuit of a fox and one who swooped in to kill the animal, the case held that the property interest of the latter was stronger. The court made clear that a definitive capture, and not pursuit alone, was necessary to establish and retain ownership of a wild animal.

In 1898, another New York case, Mullett v. Bradley, went further by recognizing that capture alone is not sufficient to claim ownership of a wild animal if the animal is able to escape and regain their liberty. The court found that a sea lion who had been brought by rail from the Pacific Ocean to the East Coast and later escaped from an enclosure in Long Island Sound was legally free until he was captured by a different person two weeks later. Cases like these gave rise to a doctrine that legal scholars now call “the law of capture,” which holds that if a captive wild animal escapes and control over them is lost, they no longer necessarily belong to the party who had previously captured them.

This line of legal reasoning generally works to the detriment of animals, ensuring that each generation of law students learns that animals are ours to possess and use for our own ends. But in the case of the escaped South Carolina monkeys, the law of capture raises doubt about whether the lab retains ownership of the animals unless and until it recaptures them.

A more recent Canadian case suggests that the law of capture may indeed offer a path to rescue for escaped animals like the South Carolina lab monkeys. In 2012, Darwin, a Japanese snow macaque, became a worldwide media sensation when he was found roaming through an Ontario IKEA store wearing a shearling coat and a diaper. While Darwin had been kept as a pet, a Canadian court ruled that he was a wild animal, and his owner lost her rights to him after he escaped from her car. Toronto Animal Services captured Darwin inside the store and transferred him to a primate sanctuary, where he could live among other macaques.

Still, one could argue that the escaped lab monkeys in South Carolina are effectively domestic animals who belong to their owner. Alpha Genesis has put resources into housing and raising them, including managing the monkey population on Morgan Island. But unlike pets who have been domesticated over many generations to live safely among humans, these rhesus macaques retain their wild instincts — they’ve been described as skittish, and food is being used to lure them into traps.

If the monkeys were to return on their own, like a house cat coming home after a day of adventure, the legal case for viewing them as domestic animals would be stronger because wild animals, once they stray, must have no animus revertendi, or intention to return. So long as these monkeys express their desire to remain free by evading capture, they should be considered wild animals. A 1917 Ontario court case, Campbell v. Hedley, involving a fox who had escaped a fur farm, established a similar principle, finding that the animal remained wild and thereby became free after fleeing the farm because they belonged to a species that “require[d] the exercise of art, force, or skill to keep them in subjection.”

There are, to be sure, cases in which common law courts have found losing control of an animal does not result in a loss of ownership. A 1927 Colorado case, Stephens v. Albers, held that a semi-domesticated silver fox who escaped from a fur farm still remained the property of that owner. And questions about the ownership of wild animals are infinitely debatable, as any good student of Pierson v. Post will tell you.

While these past cases offer important insight into the treatment of wild animals under common law, none of them took place in South Carolina, so courts in that state could consider them for guidance but wouldn’t be required to follow them when deciding who owns the escaped Alpha Genesis monkeys (and nothing in this piece should be construed as legal advice).

The moral meaning of animal escapes

Yet the law of capture aside, the plight of these monkeys is also interesting to us as legal scholars because it highlights one of many disconnects between the law and our moral intuitions about animals who have escaped and who are seeking or being afforded sanctuary. As journalist Tove Danovich has written, there is often great public sympathy and compassion for animals who escape painful confinement or slaughter at zoos, factory farms, or research labs — even among people who might otherwise tolerate the very systems that normalize those animals’ suffering. The public’s outrage when a single cow who escapes slaughter is gunned down by authorities is palpable and crosses ideological lines.

There is something enchanting and powerful, even romantic, about the idea of an animal escape, especially if it results in the animal’s rescue from confinement. Yet the law generally fails to recognize the moral tug that these escapes place on our collective conscience.

In a recent high-profile case in upstate New York, two cows wandered onto an animal sanctuary after escaping from a neighboring ranch. Unlike the South Carolina monkeys, these were straightforwardly domesticated animals, and the response from local law enforcement was harsh.

The sanctuary owner, Tracy Murphy, was arrested, shackled, and faced criminal liability for taking the cows in and refusing to immediately turn them over for slaughter (one of us, Justin, was defense counsel for Murphy, whose case was dismissed last month after a two-year legal battle). Her aid to two escaped cows was widely vilified by her own neighbors and by local law enforcement, because our legal system continues to treat many animals as property without any recognized rights or interests of their own.

The law is unlikely to swiftly abandon the archaic notion of human ownership over nonhuman animals. But we believe the law does implicitly recognize a right to rescue escaped animals, at least those who are lucky enough to make it on their own steam. We hope that the case of the escaped South Carolina monkeys will inspire conversations about the right of at least some animals to liberate themselves from exploitation and harm at human hands. Escapes are rare, but when they happen against all odds, we might ask ourselves, on both legal and moral grounds, whether the animals have a claim to freedom.