Editor's Note: The text of this story was updated on April 22, 2015.
Two chimpanzees named Hercules and Leo got their day in court Tuesday. The pair have been used for biomedical experimentation at Stony Brook University on Long Island, New York.
A New York State judge signed a writ of habeas corpus on behalf of the primates—a move that effectively granted the animals legal rights as humans—and then reversed the decision shortly after, saying she had gone too far.
An organization called The Nonhuman Rights Project filed the case on behalf of the chimps.
In a previous case, a chimpanzee named Tommy and three of his pals sued their captors in order to prove that they are not things, but persons. But a New York appeals court ruled unanimously against Tommy and the other chimp plaintiffs in December 2014.
In April 2014, Steven Wise, president of the Nonhuman Rights Project, told The Takeaway that science proves that these apes, alongside elephants, cetaceans like dolphins and whales, and African grey parrots, are among a class of nonhuman animals that exhibit high cognitive ability. He argues that they're self-aware, they experience pain and joy and they suffer terribly from confinement.