Pandamonium

Panda-birthing season is underway at the reserve, forcing staff to intervene in a complicated birth.

Tensions run high at the reserve as You You the panda endures a long and difficult labor.

Mei Sheng the panda leaves the San Diego Zoo for Wolong, and the cubs are separated from their moms.

Panda behavior is observed during mating season at China's Wolong National Nature Reserve.

As another year draws to a close, the staff takes a look at how far the pandas have progressed.