PORTLAND, Ore. (KOIN) — The Oregon Zoo announced Saturday it is had to say goodbye to its oldest resident, Sumatran orangutan Inji, who at 61-years-old was thought to be the oldest orangutan in the world.

“We knew she couldn’t live forever, but this really hurts, and I know many visitors are grieving along with us,” said Bob Lee, who oversees the zoo’s animal areas. “Inji’s ability to connect with people was incredible. She inspired generations.”

Lee said the orangutan seemed to study humans and enjoy watching them, especially children and remained active and inquisitive all through her golden years. Inji was known to go up to the windows of her habitat, curious about what was inside people’s purses, handbags and backpacks.

“Some volunteers, staff and guests would make a point to carry wind-up toys or brightly colored items in their bags just to show Inji,” Lee said.

At 61, Inji was much older than most orangutans, who seldom live past the age of 40.

Though she remained healthy for the better part of the last decade, Lee said Inji’s health began deteriorating over the past few weeks. She moved stiffly, rarely left her nest box and was no longer interested in her favorite foods.

After it became apparent Saturday her pain medications were not helping, veterinary and care staff made the difficult decision to humanely euthanize her.

The animal’s actual birth date is unknown. Inji was born in the wild around 1960. She came to the U.S. through the then-legal wild animal trade and was brought to the zoo by her owner in 1961. It was estimated she was about a year old when she arrived on Jan. 30, 1961.

With threats from the now-illegal wild animal trade and humans’ encroachment and habitat loss from palm oil plantations, orangutans are at the brink of extinction–especially in Sumatra, where Inji came from, said Asaba Mukobi, the zoo’s senior primate keeper.

All three orangutan species are considered critically endangered, with fewer than 800 Tapanuli, 15,000 Sumatran and 55,000 Bornean orangutans believed to remain.

Zoo staff plan to honor Inji in the opening of the Primate Forest, scheduled to be open this spring.