PHILADELPHIA (CBS) The Philadelphia Zoo has announced Jabari, a 28-year-old male western lowland gorilla, died Friday afternoon.

The Zoo says Jabari exhibited appetite loss and signs of mouth or throat discomfort Thursday.

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The veterinary team decided to conduct a full examination, but Jabari stopped breathing once under anesthesia and resuscitation attempts were not successful.

Jabari was born at the Brookfield Zoo in Chicago on February 5, 1985 and arrived in Philadelphia from the St. Louis Zoo on July 13, 2004.

During his nine years in Philadelphia, the Zoo says Jabari was one of the most beloved animals and the largest animal in their primate reserve.

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“We are shocked and deeply saddened by this tremendous loss,” said Dr. Andy Baker, Chief Operating Officer at the Philadelphia Zoo in a statement. “Jabari was an iconic favorite with our staff and visitors, and we expected him to be with us for many years.”

The Zoo says gorillas may live as long as 50 years in zoos, with a more typical lifespan in the mid-30’s.

The Zoo is currently conducting a necropsy to determine the cause of his illness and death.

The Philadelphia Zoo is home to four other western lowland gorillas, including Jabari’s son Louis, a 14-year-old male, Kira, a 14-year-old female, Honi, an 18-year-old female, and Honi’s son Kuchimba, an 11-year-old male.

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Western lowland gorillas are listed as Critically Endangered on the IUCN Red List for Threatened Species.