Trudy, believed to be the oldest Western lowland gorilla in captivity, has died at the age of 63, the Little Rock Zoo announced Thursday night. She lived at the zoo for over 31 years.

"At the age of 63, Trudy outlived most of her counterparts in zoos around the world and in the wild," the zoo said in a press release. Her keepers said she was the "queen" of the group, describing her as "spunky."

It is with heavy hearts the Zoo announces the passing of Trudy, the beloved eldest member of our Western Lowland... Posted by Little Rock Zoo on Thursday, July 25, 2019

Trudy was brought to the U.S. from Africa as an infant in 1957, a practice the zoo said is "fortunately" no longer allowed. She was transferred to the Little Rock Zoo from the Buffalo Zoo in the spring of 1988 with fellow gorilla Ollie. They were the first gorillas ever exhibited in Arkansas, the zoo said.

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According to the zoo, Trudy was one of the last "wild caught" gorillas to be held in a zoo in the U.S. The practice is no longer followed, and most gorillas currently in North America were born in zoos.

Trudy was a "hardy gal that did what she wanted to do when she wanted," said former keeper Syd Tanner. She "was the boss lady."

"There are so many memories, stories and anecdotes to share about Trudy," Little Rock Zoo Director Susan Altrui said. "She is a cherished member of the Little Rock Zoo family. To say that she will be missed and that her absence is felt is an understatement. We are glad to know she had a good home with us here."

According to Smithsonian's National Zoo and Conservation Biology Institute, Western lowland gorillas are critically endangered, plagued by exceptionally high levels of disease and hunting. Their population has declined by more than 60 percent in past two decades.

Trudy lived much longer than expected. Western lowland gorillas typically live for 30-40 years in the wild and 50 years in captivity.