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SAN FRANCISCO (CBSNEWS) – Uulu, a 545-pound female polar bear and a principal attraction at the San Francisco Zoo, died Friday at the age of 36, according to a statement released by zoo officials, CBS San Francisco reports.

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The cause of death was given as congestive heart failure and advanced age. Indeed, Uulu was among the oldest polar bears in any zoo in the world and was the subject of several studies on aging animal care.

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Uulu was rescued from Manitoba in Canada’s far north at the age of 3 and spent the next three decades in San Francisco.

“We are all tremendously saddened by the passing of our polar bear. She was an amazing animal ambassador and helped to educate millions of visitors over the years about polar bear conservation,” San Francisco Zoo president Tanya Peterson said in a statement Friday.

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At the time of her death, Uulu was the only polar bear at the zoo. Her name derives from an Eskimo word for a crescent-shape knife, also spelled “ulu.”