World's oldest orangutan dies at the age of 55

(INSIDE EDITION) - The world's oldest orangutan has died.

Maggie, the beloved 55-year-old Bornean orangutan, was euthanized at Illinois' Brookfield Zoo on Friday.

Maggie, who was born in captivity at the San Diego Zoo in 1961, showed a gradual decline in her health, as degenerative changes associated with her advanced age began to severely impact her quality of life, zoo officials said Saturday.

"Described as curious, intelligent, and playful by the primate staff who cared for her, Maggie will be truly missed," zoo officials said.

Maggie was the oldest known female Bornean orangutan worldwide and had given birth to four offspring. In 1995, she arrived at Brookfield Zoo and served as a surrogate mother to two infants.

The most recent is Kecil, who is now 2½ years old.

"From the day Maggie and Kecil were introduced to each other, staff noticed positive interactions. With her calm demeanor, Maggie engaged Kecil in play, slept with him, and when he first ventured out to his new habitat in Tropic World: Asia, she was always protective and nearby," zoo officials said.

In Maggie's absence, Kecil and a 7-year-old female orangutan are being slowly introduced to one another.

The decision to euthanize Maggie came after she began to suffer many of the same ailments seen in aging humans including arthritis, heart disease, hypothyroidism, and round cell sarcoma.

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