Pan Pan, a giant panda whose virility helped spawn an entire generation of the notoriously difficult-to-breed animals, died this week at a conservation center in China’s Sichuan Province.

At 31, Pan Pan was thought to be the world’s oldest male panda. He died early Wednesday morning at the China Conservation and Research Center for the Giant Panda, according to Xinhua, the state-run news agency in China. Pandas in the wild generally live to be about 20, but often survive longer in captivity.

“Pan Pan was the equivalent to about 100 human years, but he had been living with cancer, and his health had deteriorated in the past three days,” Tan Chengbin, a keeper at the conservation center, told Xinhua.

Pandas International, a Colorado-based charity that supports conservation efforts, mourned the loss of Pan Pan in a blog post that described a visit to China in July to celebrate his 31st birthday.