Only 3 northern white rhinos remain in world after Nola dies in San Diego

Nola, one of only four known northern white rhinos in the world, was euthanized Sunday after her health rapidly deteriorated last week. The 41-year-old rhinoceros came to California's San Diego Zoo Safari Park in 1989.

Nola suffered a variety of ailments in recent years, according to the Los Angeles Times, including arthritis, sinus conditions and a long-running abscess on her hip. The 4,500-pound rhino's condition went downhill in the last week following surgery to determine the source of the chronic infection.

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"In the past 24 hours Nola's condition had worsened significantly," the Safari Park said in a statement on Sunday. "Early this morning, the team made the difficult decision to euthanize her."

Angalifu, a male northern white rhino, died of cancer at the Safari Park at the age of 44 last December.

Only three more northern white rhinos remain in the world, all held at a guarded sanctuary in Kenya.

"Nola was an iconic animal, not only at the Safari Park but worldwide," the Safari Park said.

Nola has been on loan at Safari Park from the Dvůr Králové Zoo in the Czech Republic since 1989. She was originally rescued from her heavily-poached home area of Sudan at a young age.

Northern white rhinos are so rare that zookeepers attempted to get Nola to mate during captivity, though without success.