The Toronto Zoo says that one of its original residents, a 49-year-old western lowland gorilla, has died.

The zoo announced the death of Josephine, a matriarch of her gorilla troop, in a news release issued on Monday.

According to officials, Josephine had started “acting abnormally” last Monday and it soon became obvious she was struggling to move.

After a week of observation and tests, the zoo said that “all treatable conditions” were ruled out.

“There were no options left to provide her with a comfortable and pain free life, and we made the difficult decision to humanely euthanize her. A post mortem investigation is currently under way to understand more about Josephine’s failing health condition,” the zoo said in a statement.

“This loss is felt deeply in our extensive zoo family, which includes our volunteers, members, and guests, and we are grateful for the expertise and compassion shown to her and her whole troop during this difficult time. The gorilla troop was provided opportunity to visit with Josephine’s body and mourn afterwards, which was important to support the gorilla troop dynamic and provide closure as they carry on without her.”

During her stay at the Toronto Zoo, Josephine gave birth to five offspring and was a grandmother to five gorillas at zoos throughout North America.

As the average lifespan of a western lowland gorilla is 35, Josephine was believed to be one of the oldest gorillas living at a zoo in North America.

“She was a spunky, sassy personality, according to her wildlife care keepers, making an impression on all those who met her,” officials with the Toronto Zoo said. “She was one of the most vocal gorillas. She would vocalize happily with a low grumble when she was eating a favorite food. She would savour every tiny bit of a treat - one fig could last her 10 minutes, as she would carefully open the fig and pick out each seed and eat it individually.”

“She had a bigger than life personality, and made her keepers laugh all the time with her antics. Her legacy lives on in her offspring, one of whom, Johari, still lives here at your Toronto Zoo.”