It was a sad week for officials at the San Francisco zoo, who lost their beloved 24-year-old black rhino, Gene, to kidney failure on Monday.

Gene, who moved to the United States from Kenya, had been a popular mainstay at the zoo since the 1980s. He was named after Eugene Friend, who served on the city's Recreation and Park commission for more than two decades.

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Julie McGilvray, Gene's keeper, described her animal as "very friendly" to the SF Appeal. "We nicknamed him Big Dog because he loved to be rubbed, either by hand or with a scrub brush, and oftentimes he would lie down and absorb the soothing experience," she said.

"He was a handsome guy!" added San Francisco Zoo Executive Director Tanya Peterson to The Huffington Post.

During his life, Gene fathered five offspring, later relocated to other zoos across the country.

According to zoo officials, black rhinos are a critically endangered species. According to a popular Eastern medicine philosophy, their ground-up horns have healing powers and can serve as an aphrodisiac, and the animals are widespread victims of poaching.

Take a look at images of Gene below (he is a handsome guy!). May he rest in peace.

PHOTO GALLERY rip gene