A rare northern white rhino has died in San Diego Zoo Sarafi Park, leaving just three across the world.
The 41-year-old female called Nola had received treatment for an infection before undergoing surgery, according to a statement from the zoo.
She was placed under vetinary watch for a week after her activity levels and appetite declined, but the zoo decided to euthanise her after she took a turn for the worse.
The 4,000-pound (1,800-kg) white rhino was the only one of her kind left in captivity in the Western Hemisphere, with her death leaving three others remaining in the Ol Pejeta Conservancy in Kenya.
"Nola was an iconic animal, not only at the San Diego Zoo Safari Park, but worldwide," the zoo said in a statement.
"Through the years, millions of people learned about Nola and the plight of rhinos in the wild through visits to the Safari Park, numerous media stories and social media posts."
Nola was known for her love of back scratches and gentle disposition, making her a favourite among zoo staff.
The species was declared extinct in the wild in 2008 because of poachers hunting them for their horns, but Nola had lived in the San Diego zoo since she was captured in 1989 at age of two.
