MIAMI (Reuters) - A Sumatran orangutan, thought to be the world's oldest, has died in Miami at age 55, a zoo spokesman said on Sunday.
Nonja, who was born in the wild on the Indonesian island of Sumatra in June 1952, was found dead on Saturday morning, Miami Metro Zoo spokesman Ron Magill told Reuters.
He said a necropsy had been performed on Saturday and that a small mass of blood had been found on Nonja's brain, pointing to a tumor or aneurysm as the likely cause of death.
Magill said one other Sumatran orangutan had lived until the age of 57. But Nonja was believed to be the oldest surviving great ape of her kind in the world, both in captivity and in the wild, he said.
Most of the animals die before they reach their mid-40s, according to Magill, who said Nonja had mothered five offspring.
"She was a grande dame and I think she knew it," he said.
Nonja was shipped to Miami from a zoo in Holland in 1983 and her name means "girl" in Dutch, Magill said.
According to the Sumatran Orangutan Society, the species has been classified as critically endangered by the World Conservation Union and could become extinct in the wild in less than 10 years. There were 7,300 Sumatran orangutans in the wild in 2003, the group said.
Nonja in 2006. 
A 55-year-old orangutan named Nonja, who was believed to be the oldest living orangutan in the world both in captivity and the wild, has died at the Miami MetroZoo in Miami, Florida.

"Everybody's very sad, especially with an animal like an orangutan. You see a lot of yourself in these animals. The great apes are our closest relatives. She was really a grand old dame," said zoo spokesman Ron Magill.

Nonja, which means 'girl' in Dutch, was born in 1952 in Indonesia on the island of Sumatra. She arrived at the Miami MetroZoo in 1983. Her death is believed to have been caused by a small brain tumor or aneurysm which ruptured.

According to the zoo, an orangutan normally only lives about 40-50 years. Orangutans are part of an endangered species and in 2003, only about 7,300 were believed to be left living in the wild.