For the third time in less than a year, a historic bid for legal rights for chimpanzees has been denied. On Friday, a New York state appeals court upheld a lower court's ruling that Kiko, a chimp owned by a couple in Niagara Falls, is not a legal person with a right to be free, or at least less-imprisoned.

The lawsuit would make United States history by providing the first legal recognition of rights in a nonhuman animal. But according to the court, the lawsuit—which seeks to have Kiko transferred from solitary life in a cage to social life in a sanctuary—would only replace one sort of captivity with another, and thus can't be considered a legitimate appeal for freedom.

Attorney Steven Wise, founder of the Nonhuman Rights Project, an animal rights group that in 2013 filed lawsuits on behalf of Kiko and three other chimps, said the court's rationale defies legal precedent. "This undermines decisions that have been coming down for 200 years in the state of New York," said Wise.

The Nonhuman Rights Project seeks personhood for chimpanzees: legal recognition of an individual chimp's capacity to possess at least some rights, though not necessarily the full complement given to humans.

In particular, they've asked New York's state courts to recognize for Kiko and the other chimps what's known as habeas corpus, or the right to challenge an unjust imprisonment. Implicit in that right is Western society's deep respect for physical liberty: no person should be owned by another, or locked up except for a very good reason.

Chimpanzees are enough like humans—thoughtful, self-aware, decision-making—to deserve that right, according to the Nonhuman Rights Project. Judges have so far disagreed. Each of lawsuits was initially denied; the decisions were appealed, and each appeal has been rejected.

In the first appeal, concerning two chimps used for research at Stony Brook University, judges decided that the Nonhuman Rights Project was not legally qualified to file a habeas corpus claim on the chimps' behalf.

In the second, involving a chimp named Tommy, judges accepted the Nonhuman Rights Project's legal standing but rejected their argument, instead adopting a somewhat controversial position that rights are linked to social responsibilities: since chimps can't be expected to fulfill duties to society, neither can they have rights.

The judges in Kiko's appeal did not reference either of those decisions. Instead, they gave their own, different rationale. "Regardless of whether we agree with petitioner's claim that Kiko is a person," wrote the judges, habeas corpus doesn't apply in his case, as Kiko wouldn't actually be granted freedom.

Rather, Kiko would simply be moved to a sanctuary–and "habeas corpus does not lie where a petitioner seeks only to change the conditions of confinement rather than the confinement itself," they wrote.

According to Wise, that interpretation of habeas corpus law ignores the many situations in which courts do recognize an individual's right to freedom without granting it unconditionally. These include centuries-old decisions in which child slaves or mistreated apprentices were moved into the custody of guardians, and more recent cases involving custody battles over elderly adults with dementia.

David Cassuto, an animal law scholar at Pace University who is not involved with the case, echoed Wise's assessment. "Under the court’s reasoning, an incompetent prisoner who could not care for herself but who was nevertheless illegally imprisoned would not be entitled to habeas," said Cassuto. "This is clearly erroneous."

Primatologist Mary Lee Jensvold, who works with chimpanzees trained to use sign language and is among the nine leading primatologists to file an affidavit on behalf of the Nonhuman Rights Project, said the court's decision ignores profound differences between types of confinement.

At a place like Save the Chimps, one of the sanctuaries to which Kiko could be transferred, he could interact with other chimps rather than living alone. Kiko would also be able to move freely about a small island, rather than being kept in a cage.

"The living conditions at Save the Chimps are far better than where Kiko is now," said Jensvold. "We use solitary confinement in our prison system."

Wise said the Nonhuman Rights Project will appeal the decisions on Kiko and Tommy to New York's highest court, and file suit again on behalf of the Stony Brook chimps. Eventually they hope to secure legal rights not only for chimps, but for individuals belonging to other species: other great apes, perhaps, or orcas.

For a case to be made, there must first be an extensive body of scientific research describing a species' cognitive abilities. Their next lawsuit, says Wise, will be filed later this year on behalf of an elephant.