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.