China, with a surface area of about 9,596,986 km3 , covers the majority of Eastern Asia.
Due to its large extension China has a quite varied geographical configuration and is of great importance from a biogeographical point of view as it is ideally crossed by a “ boundary line” which divides the paleo-artic zone to the north from the tropical one to the south. This line is not always easily identified, at least with regard to the distribution of some animals.
The vast Chinese territory is two-thirds mountain or desert while 14% of its surface area is of a carbonate nature. The latter is concentrated above all in the southern regions of the country (Guizhou, Guangxi, Yunnan, Hunan).
The subtropical climate of this zone contributes in determining the rapid and massive karstification of calcareous rocks and therefore the formation of caves which are found to be numerous and of enormous dimensions.