The Woodland Park Zoo’s 50-year-old gorilla Amanda was humanely euthanized Wednesday after her health severely declined, the zoo said in a news release.

She became the zoo’s oldest animal after an orangutan named Chinta died in February at age 51.

“Known for her sweet disposition and being an exceptionally good mom, Amanda showed attentive, nurturing maternal love and care for her daughters,” mammal curator Martin Ramirez said in a news release. “We are going to deeply miss this beautiful animal.”

Amanda came to Seattle from the Toronto Zoo in 1994. She raised three daughters at Woodland Park Zoo, including Uzumma, the mother of baby Kitoko. With Amanda’s death, there are now eight gorillas living at the zoo.

A look inside Seattle’s Woodland Park Zoo during the coronavirus shutdown

Amanda’s appetite and activity level had declined over the past few weeks, the zoo said. The zoo will perform pathology tests and a necropsy to determine the cause of death.

She had been living in a private den since the fall after losing her vision, but the zoo built her a special sunning yard so she could safely go outside.

Female gorillas have a life expectancy of 30 to 35 years in the wild, but can live into their 40s and 50s in zoos. Amanda was among the oldest in North America. The western lowland gorilla is critically endangered, with an estimated population of 300,000 in the wild.

It’s been a rough week for the zoo’s gorilla family. Over the weekend, 2½-month-old Kitoko was seriously injured in a family altercation but was expected to recover.