Evolution of Giant Pandas (Ailuropoda melanoleuca)

Distant Ancestor - 11.6 million years ago

1 CE

The oldest discovered ancestor to the Ailuropoda melanoleuca line is the Kretzoiarctos beatrix, whose fossils were found in modern-day Spain. It weighed no more than 130 pounds/60 kilograms, its size being on par with the smallest known living bear species, and was most likely an omnivore. Its dental features show some kind of adaptation to eating tough plant materials.

European Panda Species Disappear/Migrate - 5 million years ago

2

Evidence suggests that some ancestors to the Ailuropoda melanoleuca resided in Europe. Far into the past, Europe was much warmer and wetter and could even be described as a subtropical forest. However, 5 million years ago, these forests dried out and decreased in general temperature, changing the fauna that could survive in the environment with it. While not enough research has been done to determine what exactly happened, the European pandas may have sought out a more viable home in China.

First Emerging of Another Ancestor - 3 million years ago

3

The pygmy panda first emerged as early as 3 million years ago, and, unlike its ancestors, took up bamboo as its primary source of food.

Ailuropoda microta - 2.4 million years ago

4

An ancestor of the Ailuropoda melanoleuca is the Ailuropoda microta, who is smaller than both the living species and the Ailuropoda baconi. An examination of the A. microta's skull, jaw, and teeth once again proved a preference for bamboo even back then, as the dental features show the panda's proficiency in grinding tough, fibrous foods. The basic cranial anatomy also supports the idea that pandas are derived from the Miocene Asian ursid Ailurarctos.

First Population Bottleneck - 0.7 to 0.3 million years ago

5

The panda population decreased drastically because of the two largest Pleistocene glaciations to occur in China. At some point during this time period, the pygmy pandas were replaced by the baconi pandas, a subspecies with a larger body frame.

Population Separates into 3 Genetic Populations - 0.3 million to 2,800 years ago

6

Around 0.3 million years ago, the panda population divided into the Qinling and non-Qinling genetic populations, the latter of which then further split into the Minshan and Qionglai-Daxiangling-Xiaoxiangling-Liangshan. A commonality between the three sections is how the pandas adapted to their environment over time. The largest cluster of selected genes concerned their sensory system, especially in regards to their odor perception.

Second Population Expansion - 30-50 thousand years ago

7

The panda population flourished and adapted to the times peacefully thanks to the warm weather and abundant alpine conifer forests in the Greatest Lake Period.