A programme that sought to save a species rather than individuals would allow each infected Wolf to pass the disease on to more than one healthy animal and hence require fewer vaccinations.

And beside all this, between us and you there is a great gulf fixed: so that they which would pass from hence to you cannot; neither can they pass to us, that would come from thence.

They are both sited on the same natural pass through the mountains to the north of Beijing and hence a critical point of defence.