Giant panda Panpan recently celebrated his 31st birthday with a cake made of ice and carrots at the China Conservation and Research Center for Giant Pandas in Sichuan province. The birthday festivities took place on Sept. 1. As the world’s oldest male panda, Panpan's age in "panda years" is equivalent to a human being reaching the age of 100. Panpan has fathered more than 130 giant pandas, or one-fourth of the world’s total captive giant panda population.