Patti Ragan, director of the Center for Great Apes in Wauchula, Florida, says Sandra "has adjusted beautifully to her life at the sanctuary" and has befriended Jethro, a 31-year-old male orangutan.

Prior to coming to Florida, Sandra had lived alone in a Buenos Aires zoo. Sandra was a bit shy when she arrived at the Florida centre, which is home to 22 orangutans.

"Sandra appeared most interested in Jethro, and our caregivers felt he was a perfect choice because of his close age, calm demeanour, and gentle nature," Ragan said in a news release. "Sandra still observes and follows Jethro from a distance while they are in the process of getting to know and trust each other. But they are living harmoniously in the same habitat spaces as they continue to gain confidence in their relationship."

Judge Elena Liberatori's landmark ruling in 2015 declared that Sandra is legally not an animal, but a non-human person, and thus entitled to some legal rights enjoyed by people, and better living conditions.

"With that ruling I wanted to tell society something new, that animals are sentient beings and that the first right they have is our obligation to respect them," she told The Associated Press.

But without a clear alternative, Sandra remained at the antiquated zoo, which closed in 2016, until leaving for the US in late September. She was in quarantine for a month at the Sedgwick County Zoo in Kansas before arriving in Florida.

On Friday, Sandra celebrated her birthday, complete with pink signs and wrapped packages. Jethro, who was once in the entertainment business, attended the party.

Australian Associated Press