A court in Argentina has ruled that a shy orangutan who spent the last 20 years in a zoo can be granted some legal rights enjoyed by humans.
Lawyers had appealed to free Sandra from the Buenos Aires zoo by arguing that although not human, she should be given legal rights.
They had argued that she was being illegally detained.
If there is no appeal, the ape will be transferred to a sanctuary in Brazil where she will enjoy greater freedom.
The singular case hung on whether the animal was a "thing" or a "person".
In December a New York State court threw out a request to free a privately owned chimpanzee arguing that the animal was property and had no legal rights.
Lawyers for Argentina's Association of Professional Lawyers for Animal Rights (Afada) said Sandra was "a person" in the philosophical, not biological, sense.
She was, they argued, in a situation of illegal deprivation of freedom as a "non-human person".
They had filed a "habeas corpus" writ in her favour last November over "the unjustified confinement of an animal with probable cognitive capability".
Afada lawyer Paul Buompadre was quoted as saying by La Nacion newspaper: "This opens the way not only for other Great Apes, but also for other sentient beings which are unfairly and arbitrarily deprived of their liberty in zoos, circuses, water parks and scientific laboratories."
The court judges had rejected the writ several times before deciding finally that Sandra could be considered to have rights to freedom which needed defending.
Sandra was born in 1986 in a German zoo and arrived in Buenos Aires in September 1994.
She regularly tried to avoid the public in her enclosure.
If there is no appeal against the court's decision from the Buenos Aires zoo, she will be transferred to a primate sanctuary in Brazil where she can live in partial liberty.