The San Francisco Zoo’s only male gorilla, a Western lowland silverback named Oscar Jonesy, died Thursday after undergoing a medical procedure.
Despite Oscar’s advanced age — he was 43, near the life expectancy of apes in captivity — his death came as a surprise. Veterinarians from UC Davis will examine the body Friday to determine the exact cause.
Dr. Adrian Mutlow, the zoo’s chief veterinarian, said in a statement that Oscar’s procedure “went well,” but his health took a turn afterward.
“Despite showing initial signs of recovery, he suddenly became unresponsive and stopped breathing,” Mutlow said.
The death sparked outrage from at least one zoo watchdog. Justin Barker, a local animal advocate who runs the blog SF Zoo Watch, said the zoo should have avoided using anesthesia, which can be dangerous to older apes.
“Since 2020, at least three silverback gorillas in U.S. zoos have died following anesthesia-related complications,” Barker wrote in a blog post. “Despite these incidents, many zoos continue to rely on outdated or high-risk anesthetic protocols without fully adopting safer alternatives.”
Reached by phone, Barker said the SF Zoo, which recently came under fire for animal welfare and safety issues, has lacked transparency for years. Just this week, the city’s Sunshine Ordinance Task Force ruled that the zoo must furnish records to Barker in response to a request he made in July, according to an email from the committee.
Barker said he now plans to request records related to Oscar’s care.
Nancy Chan, a spokesperson for the zoo, did not immediately respond to a question about which anesthetics were used for Oscar’s procedure. Attempts to reach zookeepers were unsuccessful.
In September, members of the SF Zoo union voted 97% to pass a vote of no confidence in director Tanya Peterson, citing animal welfare concerns. Peterson remains director of the zoo.
Oscar was the third-oldest male ape in the United States. While living in San Francisco, he fathered two children; one now lives in Los Angeles, while the other was crushed and killed by a hydraulic door at the SF Zoo in 2020.
“As the troop’s leader, he provided a sense of calm and mediated conflict,” Dominick Dorsa, a zoo administrator, said in a statement. “The females in our troop definitely deferred to him, and we are giving them the opportunity to mourn his passing. We will be monitoring the remaining troop as they go through a mourning period.”