Who says a lady never reveals her age? On Thursday, the Philadelphia Zoo celebrated the 37th birthday of a very special lady – Coldilocks, who holds the distinction of being the oldest polar bear in the country. Wearing her finest fur, Coldilocks made an appearance as the guest of honor, while zoo guests sang "Happy Birthday to You" and snapped photos of the birthday girl. And, because it's not a party without cake, Coldilocks was treated to a frozen confection made of peanut butter, fish, carrots, raisin and bear chow.  Not exactly an ice cream cake, but she seemed to enjoy it.

Coldilocks came to the zoo as a baby 36 years ago in 1981 after being born at the Seneca Park Zoo in Rochester, N.Y. Currently the zoo's only polar bear, she has exceeded the average lifespan of a polar bear in captivity, which is about 25 years, and is still doing well, according to Donna Evernham, curator of carnivores and ungulates for the Philadelphia Zoo. While the celebration was held today, her actual birthday was Dec. 13.

One of the zoo's most significant animal ambassadors and favorite residents, Coldilocks has played a vital role in educating visitors about climate change while inspiring them to take steps in their everyday lives, like saving energy, to help her wild cousins.

Just this week, a video viewed by millions online shows what appears to be a starving polar bear on iceless land. According to National Geographic, "it's a symbol of what many polar bears may face in a warming climate." Polar bears are listed as "vulnerable" on the International Union for the Conservation of Nature (IUCN) red list of threatened species.