Cobby, a 63-year-old chimpanzee who was the oldest male chimp in captivity at an accredited U.S. zoo, died on Friday at the San Francisco Zoo.
While the zoo says Cobby's cause of death is not yet confirmed, officials noted that he had recently been ill. They also suspect that old age was a contributing factor to his death.
According to Chimpanzee Sanctuary Northwest, most chimpanzees have a median life expectancy of about 32 years for males and 39 years for females, though they have been known to live into their 60s in captivity.
"Our hearts are broken with this devastating loss," said Tanya M. Peterson, the CEO and executive director of San Francisco Zoological Society in a press release. "Cobby was both a charismatic and compassionate leader of our chimpanzee troop. For so many years, he was a protective companion, demonstrating patience and resiliency. He also was a favorite of visitors and staff, recognizing so many of us. He was one of the first animals whom I personally knew as director. His death will be felt deeply by our staff, many of whom cared for him for decades."
According to a press release, Cobby was born in the 1950s and raised by humans as a performing chimpanzee. He arrived at the San Francisco Zoo in the mid-1960s, where he would make his permanent home.
The zoo notes that Cobby has lived with two female companions, Minnie and Maggie, for more than 42 years. The zoo noted that Cobby's death would be "especially hard" for his two friends.
The zoo noted that Cobby had a special relationship with Minnie, who they described as his "favorite girl."
The zoo noted that Cobby enjoyed resting on various platforms, snacking and interacting with his caretakers.
"According to the staff who cared for him, they say that what they will miss most is how he expressed his 'goodnight' to them with a soft pant-hoot," the zoo said in a press release.
The zoo also credited Cobby with helping integrate four new chimpanzees into the zoo in recent years. A press release described Cobby as a "respected elder who was able to bring together this newly formed group."
"Cobby was part of San Francisco," Peterson said. "He touched so many lives, and people have so many memories of him. He is irreplaceable, and our hearts are broken. We will all miss seeing his handsome grey beard watching over us from the top platform of the yard."
According to the World Wildlife Foundation, chimpanzees are considered endangered throughout the world.