Update, 21 April: Science has learned that the court order referred to in this story has been amended. The words “writ of habeas corpus” have been struck out, suggesting that the court has made no decision on whether Hercules and Leo—two research chimpanzees at Stony Brook University in New York—deserve to be treated as legal persons. The Nonhuman Rights Project has responded to the amendment, stating, “This case is one of a trio of cases that the Nonhuman Rights Project has brought in an attempt to free chimpanzees imprisoned within the State of New York through an ‘Article 70-Habeas Corpus’ proceeding. These cases are novel and this is the first time that an Order to Show Cause has issued. We are grateful for an opportunity to litigate the issue of the freedom of the chimpanzees, Hercules and Leo, at the ordered May hearing.” Stony Brook has also issued a statement about the case: “The University does not comment on the specifics of litigation, and awaits the court's full consideration on this matter.” 
 
 Update, 22 April: The court hearing has been moved back from 6 May to 27 May. At that time, the judge will hear legal arguments regarding whether Hercules and Leo should remain at Stony Brook. 
 
 In a decision that seems to recognize chimpanzees as legal persons for the first time, a New York judge today granted a pair of Stony Brook University lab animals the right to have their day in court. The ruling marks the first time in U.S. history that an animal has been covered by a writ of habeas corpus, which typically allows human prisoners to challenge their detention. The judicial action could force the university, which is believed to be holding the chimps, to release the primates, and could sway additional judges to do the same with other research animals. 
 
 “This is a big step forward to getting what we are ultimately seeking: the right to bodily liberty for chimpanzees and other cognitively complex animals,” says Natalie Prosin, the executive director of the animal rights organization, the Nonhuman Rights Project (NhRP), that filed the case. “We got our foot in the door. And no matter what happens, that door can never be completely shut again.” 
 
 Richard Cupp, a law professor at Pepperdine University in Malibu, California, and a noted opponent of personhood for animals, cautions against reading too much into the ruling, however. “The judge may merely want more information to make a decision on the legal personhood claim, and may have ordered a hearing simply as a vehicle for hearing out both parties in more depth,” he writes in an e-mail to Science. “It would be quite surprising if the judge intended to make a momentous substantive finding that chimpanzees are legal persons if the judge has not yet heard the other side’s arguments.” 
 
 The case began as a salvo of lawsuits filed by NhRP in December 2013. The group claimed that four New York chimpanzees—Hercules and Leo at Stony Brook, and two others on private property—were too cognitively and emotionally complex to be held in captivity and should be relocated to an established chimpanzee sanctuary. NhRP petitioned three lower court judges with a writ of habeas corpus, which is traditionally used to prevent people from being unlawfully imprisoned. By granting the writ, the judges would have implicitly acknowledged that chimpanzees were legal people, too—a first step in freeing them. 
 
 The judges quickly struck down each case, however, and NhRP has been appealing ever since. Today’s decision is the group’s first major victory. In her ruling, New York Supreme Court Justice Barbara Jaffe orders a representative of Stony Brook University to appear in court on 6 May to respond to NhRP’s petition that Hercules and Leo “are being unlawfully detained” and should be immediately moved to a chimp sanctuary in Florida. Both animals have been used to understand the evolution of human bipedalism. (Stony Brook did not immediately respond to a request for comment.) 
 
 Prosin says that even if NhRP loses the case, it will use the habeas corpus ruling to sway judges in other jurisdictions. “It strengthens our argument that these nonhuman animals are not property,” she says. The group plans to file another case—this one involving a captive elephant—by the end of the year and has set its sights on other animals, including research animals, across the country. “We have the scientific evidence to prove in a court of law that elephants, great apes, and whales and dolphins are autonomous beings and deserve the right to bodily liberty,” she says. 
 
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 Hercules and Leo, the research chimpanzees whom an animal rights group went to court to set free, will stay put because chimps aren't "legal persons," a New York judge ruled Thursday. 
 
 The Nonhuman Rights Project, a non-profit activist group in Coral Springs, Florida, sued on behalf of the 8-year-old chimps in March, arguing that they're autonomous, intelligent creatures and that holding them at the State University of New York at Stony Brook is illegal imprisonment. It said Thursday it would appeal the ruling. 
 
 In a ruling filed Thursday in Manhattan, New York State Supreme Court Justice Barbara Jaffe turned down the group's request to approve a writ of habeas corpus — the legal mechanism under which people are freed from unlawful detention. But she indicated that she sympathized with Hercules, Leo and their supporters.
– The writ of habeas corpus lets prisoners appear in court to make their captors justify why they're being held. Until now in the US, those who've used this legal tactic have been human. But a New York judge yesterday ruled that the writ may be used by two lab chimpanzees at Stony Brook University, Science magazine reports. NY Supreme Court Justice Barbara Jaffe ordered a university rep to address a suit filed by the Nonhuman Rights Project by appearing in court May 6 to argue why the college is holding Hercules and Leo. The group, which says the animals are being detained for biomedical experiments, says its ultimate goal is to have the animals released to the Save the Chimps sanctuary in Fort Pierce, Fla., per the NhRP's website. "This is a big step forward to getting what we are ultimately seeking: the right to bodily liberty for chimpanzees and other cognitively complex animals," Natalie Prosin, the project's executive director, tells Science. The case kicked off in December 2013 with lawsuits that also included two chimps held on private property; each case was struck down, sending the NhRP down the appeals path. Not everyone's convinced the upcoming hearing will mean liberation for the chimps. A Pepperdine University law professor tells Science that the judge likely just wants to hear both sides of the story: "It would be quite surprising if the judge intended to make a momentous substantive finding that chimpanzees are legal persons" without doing so, he notes. Prosin, meanwhile, says her group isn't stopping with the chimps and will also target the release of other animals. (Click to read about what chimps talk to each other about.)