The first panda fossil appeared in the late Miocene, when human evolution was still in the ape period. Found in the lignite strata of Lufeng and Yuanmou in northwest Yunnan, it shows that their living environment is close to swamp, and their food is not entirely dominated by bamboo. Later, due to the distribution of giant pandas in a special ecological environment, bamboo was planted, which was widely distributed and had few competitors. The original pandas may be the ancestors of modern giant pandas. After the discovery of Lufeng fossil, it was confirmed as Ailurarctos lufengensis through research. Later, an maxillary fossil with partial cheekbones (199 1) was found in Yuanmou, and it was named A.yuanmouensis. From the fossil point of view, they are slightly smaller than the giant panda species discovered in the early Pleistocene. Their premolars are similar to those of the giant panda race and have the characteristics of the giant panda family today. Although only the first panda fossil was found in northwest Yunnan, it is the earliest known ancestor type of giant panda, and China is probably the ancestral home of giant panda ancestors who have been searching for a century.

In the late Miocene, the representative of the early giant panda was also found in the lignite strata of France and Hungary, named Agriarctosgoali, and the fossil specimens were preserved in Hungary. Their teeth have some other progressive characteristics of the giant panda, which appeared relatively late, so they tend to think that they are only an extinct collateral of the giant panda, leaving no immediate modern offspring.

A progressive branch of the original panda, by the early Pleistocene (about 6.5438+0.8 million years ago), had evolved into a species of Ailuropoda microta, belonging to the genus Ailuropoda. They spread to Guangxi, Shaanxi Qinling and other vast areas. But in the middle of Pleistocene, 600,000 ~ 700,000 years ago, the giant panda was gradually extinct in struggle for existence, and was replaced by the giant panda which had undergone many changes in temperature and warmth and further increased in size. Because the skull structure of this giant panda is not essentially different from that of the giant panda, it can be regarded as the same species. However, judging from the size of the skull, it is still quite large, which is different from living species. Therefore, most scholars agree to name it A. m. baconi, also known as Pasteurella panda. They not only spread all over the southeast of China, but also appeared in Southeast Asian countries around China, achieving unprecedented prosperity. Until 18000 years ago, after the arrival of the last (fourth) ice age peak, the climate became cold, and Himalayan orogeny and crustal uplift led to the gradual decline of Papilio panda. By the end of the last ice age about 65438+200,000 years ago, this subspecies had been extinct in large numbers. With the rise of mankind, a large number of valleys and foothills in the Yangtze River and Pearl River basins have been reclaimed in the south of Qinling Mountains. Only in the transition zone from the middle and upper reaches of the Yangtze River to the eastern part of the Qinghai-Tibet Plateau, there are large areas of virgin land, with little human interference and stable climate. Today's giant pandas can survive here. Their size is smaller than that of Papilio panda 1/8 ~ 1/9. This species that survived cruel natural selection still lives in the forests of Qinling, Minshan, Qionglai, Xiangling and Liangshan.

Fossil records show that it was once distributed in the Yellow River, Yangtze River and Pearl River basins in the southeast, Zhoukoudian in Beijing in the north and Vietnam, Thailand and Myanmar in the south. It is a major member of the giant panda-Saber-toothed elephant fauna in southern China. Due to the influence of geology, climate change and human activities, the current distribution is limited to10200' ~1081'e, 27 53' ~ 35 35' N, Qinling mountains, Gansu and Shaanxi (from the upper reaches of the Yangtze River to Qinghai-Tibet). Qionglai Mountain is located in Baoxing, Wenchuan, Tianquan, Dayi, Lushan, Qionglai, Chongqing, Kangding and Luding in Sichuan Province. It is distributed in Hongya, Mianning, Shimian and Jiulong counties in Daxiangling. In Liangshan, it is mainly distributed in Mabian, Meigu and Yuexi in Sichuan. The suitable distribution of giant pandas should be bamboo forests with abundant water resources.

Source:

Zang Zhenhua. Study on the richness pattern and hot spots of rare and endangered species in giant panda distribution area [D]. Tutor: Li Junqing; Shen guozhen. Beijing Forestry University, 20 15.

Wu Jianguo, Lv Jiajia. Potential impact of climate change on the distribution of giant pandas [J]. Environmental Science and Technology, 2009, (12):168-177. ISSN: 1003-6504。

Hu. The origin and evolution of the giant panda [J]. China Forestry, 2008, (22): 30-35. ISSN: 1000-0623。