Re: The monsters are gone now, come down!
"When the better living conditions are full of monsters or endemic disease. Somewhere in the past, something nasty arrived to decimate panda populations."
It's possible that the 'monsters' are us. Homo sapiens. A study (summarized in a recent issue of The Economist) hypothesizes that it was the spread of humans that drove pandas into marginal ecosystems. Where the only thing left to eat was bamboo.
Ancient people and their possible taste for panda meat no longer being an issue, it now appears that pandas might be able to co-exist with us, given their mellow dispositions (as demonstrated by this incident). Many animals that we neither compete with nor consume can adapt to human presence if they become acclimated to us.