SAN FRANCISCO – The oldest male chimpanzee to live in an accredited North American zoo died at the San Francisco Zoo & Gardens on Saturday. He was 63.

The chimpanzee named Cobby was a hand-raised chimpanzee before it was brought to the San Francisco Zoo in the 1960s. Although the zoo said in a press release that the cause of death of the chimpanzee was not clear, the animal was recently sick and zoo officials believe age is a factor.

The International Union for Conservation of Nature lists chimpanzees as endangered, and they are considered the most endangered primates in Africa due to hunting, habitat loss and disease.

The average life expectancy of 100,000 to 200,000 chimpanzees living in the wild is 33 years, while in human care it is between 50 and 60 years, the zoo said.

Cobby was instrumental in bringing the San Francisco Zoo’s chimpanzee population together, officials said, acting like the oldest of the troop.

“Cobby was part of San Francisco,” said Tanya M. Peterson, executive director of the San Francisco Zoological Society, in a statement. “He has touched so many lives and people have so many memories of him. He is irreplaceable and our hearts are broken. We will all miss the way his beautiful gray beard watches over us from the top platform of the courtyard.”