SAN FRANCISCO (CBS San Francisco) — Cobby, the oldest male chimpanzee in captivity in the United States, has died at the San Francisco Zoo at the age of 63, officials announced Sunday.

The cause of death was still being determined but he had recently been ill and old age was also likely a contributing factor.

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Cobby the Chimp

Cobby, chimpanzee at the San Francisco Zoo, died at age 63. (Photo by May Woon)

“Our hearts are broken with this devastating loss,” said Tanya M. Peterson, CEO and Executive Director of San Francisco Zoological Society. “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.”

Cobby’s companions for more than 42 years were females Minnie and Maggie. A third female, Tallulah, passed away in 2013.

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“His absence will be especially hard for them,” zoo officials said in a statement.

Brought to San Francisco in the mid-1960s, Cobby and his companions were favorites with millions of zoo visitors as they lived together at Triple Grotto, an outdoor moated exhibit.

Before he was placed at SF Zoo, Cobby was a performing chimpanzee who was human-reared.

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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.