Wu Daifu has worked with pandas since he was 21, but he says the 2008 Wenchuan earthquake transformed his relationship with the animals - personally and professionally.

The 36-year-old had worked as a keeper - feeding bears and cleaning cages - until Wolong National Nature Reserve's post-disaster reshuffle saw him appointed chief of the department responsible for introducing captive pandas into the wild.

"We've since discovered many things," Wu says. "We used to believe pandas would get sick without human intervention. But they're stronger without it. It actually does more harm than good. That's why wild pandas are more resilient."