In the evolution history of animals and in the competition of survival, giant panda has already been one of the winners.
Analysis over already found fossils indicates that, in late Miocene that is about 8 million years ago, at the edge of the tropic humid forest around Lufeng Area in Yunan Province of China, there had lived the ancestor of giant panda - The primal panda (Ailuaractos Lufengensis), which is the earliest panda appeared that evolved from arctoid with carnassial food habit. The figure of the primal panda is like a fat fox. A lineage evolved from the primal panda is Agriarcros Goaci, which had been inhabiting in the humid forest around Hungary and France in Europe and were extricated in late Miocene. While the main lineage of primal giant panda continued its evolution in central and south China, one branch of which appeared in early Pleistocene about 3 million years ago, with a half size of the giant panda that we see today, mostly like a fat dog. The fossil of this branch is named as Ailuropoda Micrta. From the fossil teeth of the Ailuropoda micrta, it is speculated to have evolved into a species of omnivorous animals which partially feed on bamboo.
2 million years later, these smaller-figured giant panda started to extend their living area to the sub-tropical humid forest, which gradually covered the former living areas of primal pandas around Yunnan, Guangxi and Sichuan. Later on, the giant panda has further adapted to the life in subtropical bamboo woods and their body grew bigger and bigger. The age of mid and late Pleistocene that is between the 500 thousand to 700 thousand years ago was the flourishing age of giant panda. The figure of the fossil Ailuropoda Milanoleuca Wulishansis is only 1/8 smaller than that of present giant panda. However, till the late Pleistocene, the figure of the fossil Ailuropoda Milanoleuea Daconi, which had been living on bamboo, became about 1/8 bigger than that of present giant panda.
During the entire Pleistocene, the distribution of fossils of giant panda subspecies is rather wide. The distribution almost covers the east and south of China, to the north including the Zhou Koudian site and to the south including Taiwan Island as well as Burma, Vietnam and North Thailand. In those remote ages, the giant panda had been living with the Smilodon, the Stegodon Sinensis Owen, the Peking Man and the Australopithecus, which formed the typical Pleistocene - Giant Panda - Stegodon Sinensis Owen fossil cluster. During mid and late Pleistocene, great environment change had occurred when large areas of glacier appeared in Qingling Mountains and those mountains on the south. Especially after the Quaternary Glacier that is about 18 thousand years ago, the Giant Panda - Stegodon Sinensis Owen fauna declined, most of the animals were extricated, and only those innumerable fossils indicated their existence. The giant panda disappeared in the north, and the distribution of giant panda in the south also shrank. Giant Panda thereafter stepped into the declining stage in its evolution history.