A landmark ruling by a court in Argentina has animal rights campaigners cheering and zoo officials likely wondering what's next. 

Sandra, a 29-year-old Sumatran orangutan at the Buenos Aires zoo, has been declared by the court a "non-human person," an important label that carries with it some basic rights — including the right to freedom. The unanimous decision by the judges came after careful consideration of a "habeas corpus" petition filed last year by the Association of Professional Lawyers for Animal Rights (AFADA). The group argued that Sandra, held captive in the Buenos Aires Zoo for the last 20 years, suffered "unjustified confinement of an animal with proven cognitive ability."

Orangutans are one of the world's most intelligent primates, with sophisticated communication skills (on par with those of a 3 1/2 year-old child) and complex critical thinking abilities. Lawyers for AFADA contended that because Sandra is likely aware of her confinement, she should not be labeled as a "thing," and instead be granted her freedom. The court agreed and have moved to transfer Sandra to a much larger animal sanctuary in Brazil. The Buenos Aires Zoo has 10 days to appeal the decision. 

"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," AFADA lawyer Paul Buompadre told the daily La Nacion newspaper.

The ruling comes only a few weeks after a similar effort in the United States failed in an attempt to gain rights for a captive chimpanzee named "Tommy." The lawsuit, filed by the Nonhuman Rights Project in New York State, sought to remove Tommy from his owner under the same habeas corpus writ. The judges in the case, however, argued against Tommy's "fundamental right to liberty" based on their view that, unlike humans, chimpanzees "cannot bear any legal duties, submit to societal responsibilities or be held legally accountable for their actions."

The group plans to appeal the decision to New York's Supreme Court.  

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