A U.S. animal rights group today filed what it said is the first lawsuit seeking to establish the "legal personhood" of chimpanzees.

The non-profit Nonhuman Rights Project asked a New York state court to declare a 26-year-old chimp named Tommy "a cognitively complex autonomous legal person with the fundamental legal right NOT to be imprisoned."

"A legal person does not mean human being, it means an entity whose interest the law takes notice of and will protect, and that's what we think chimpanzees should be as well, because they're so extraordinarily autonomous and otherwise cognitively complex," said the group's president, Steven Wise.

The lawsuit seeks a declaration that Tommy's "detention" in a "small, dank, cement cage in a cavernous dark shed" in central New York is unlawful and demands his immediate release to a primate sanctuary.