San Francisco Zoo's beloved polar bear dead at 36

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