The Philadelphia Zoo has thrown a birthday party for 37-year-old Coldilocks, the oldest polar bear in the United States.
The zoo says they celebrated her birthday Thursday with a cake made of peanut butter, honey, raisins and fish. Guests at the party braved a cold, icy day to sing "Happy Birthday" to the bear.
Zoo officials say the average lifespan for polar bears in captivity is 23 years. They credit Coldilocks' long life to the care she receives from her keepers and veterinary staff.
Coldilocks lived with her partner Klondike for more than three decades before the bear died in 2015 at age 34.
Polar bears as a species are listed as vulnerable. The U.S. Fish and Wildlife Service estimated in January that about 26,000 specimens remain in the wild.