SAN FRANCISCO (CBS SF) — 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.

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.

READ MORE: Fremont Police Release Body Cam Footage In Fatal Shooting Of Suspect On Highway 84

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

READ MORE: Man Arrested Following Pursuit, Multiple Hit-&-Run Crashes In San Bruno

“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.

At the time of her death, Uulu was the only polar bear at the zoo, having lived alone since Pike, another female, died two years ago at age 32.

MORE NEWS: COVID Job Market: Signs Of Recovery As California Adds Jobs For 2nd Month

Uulu’s name derives from an Eskimo word for a crescent-shape knife (also spelled “ulu”).