An animal rights group is fighting for chimpanzees in the US to be given rights as legal people so they are ensured better treatment.
Nonhuman Rights Project, a non-profit group founded by Massachusetts lawyer Steven Wise, is applying to New York courts for a ruling that the chimps are not things to be possessed and caged by people and should be released from "illegal detention."
The group is seeking an order, on behalf of four chimps, for their release to a sanctuary to live out their lives with other primates in a natural outdoor setting.
"In this case, we are claiming that chimpanzees are autonomous," Mr Wise said. "That is, being able to self-determine, be self-aware, and be able to choose how to live their own lives."
He does not expect the decisions to be favourable because the judges have no legal precedent to rely on. But he said he would take the case to appeal.
"These are the first in a long series of suits that will chip away at the legal thinghood of such non-human animals as chimpanzees," he said.
The group says it is dedicated to changing the common law status of some species other than humans. The lawsuits include affidavits from scientists who say chimpanzees have complex cognitive abilities, such as awareness of the past and the ability to make choices, and display complex emotions such as empathy.
"Once we prove that chimpanzees are autonomous, that should be sufficient for them to gain legal personhood and at least have their fundamental interests protected by human rights," Mr Wise said.
If the lawsuits succeed, similar ones could eventually be filed on behalf of other species considered autonomous, such as gorillas, orang-utans, whales, dolphins and elephants, he said.
The group applied to the state Supreme Court in Fulton County, New York, on behalf of Tommy, an adult male chimp owned by Patrick Lavery and kept in a cage in a shed with only a television to keep him company.
A second lawsuit was filed in Niagara Falls on behalf of Kiko, who lives in a cage in a brick building of the non-profit Primate Sanctuary there. Owners Carmen and Christie Presti have said they plan to move Kiko and other monkeys to a new facility on a large rural property.
A third lawsuit will be filed on behalf of two chimpanzees being used in research at Stony Brook University on Long Island.