The giant panda, a rare animal unique to China, is still a carnivore, although it mainly eats vegetarian food. In terms of external morphology and internal organs, giant pandas are not only similar to carnivorous bears, but also have the characteristics of raccoons. Taxonomists have set up a separate giant panda family for giant pandas. Compared with other carnivores, the cracked teeth of giant pandas have degenerated, the chewing surface of molars has widened, and plants are the main food. The origin and taxonomic status of giant pandas have been debated in academic circles since their naming in 1869. In addition to the special shape and structure of the living giant panda itself, I'm afraid the main reason is the lack of fossil basis.
In the past century, paleontologists have found hundreds of sites with giant panda fossils buried in Asia, mainly in China, and have a clear understanding of the evolution of giant pandas since 2 million years. Whether it is the early Pleistocene small species of giant panda or the middle and late Pleistocene subspecies of giant panda Pasteur, they are not fundamentally different from the living giant panda in the shape and structure of skull and teeth at least.
The small species of giant panda living 2 million years ago is only about half the size of the living giant panda. It is the most primitive species in the genus giant panda. According to the tooth wear marks and chewing characteristics, it can be inferred that the daily diet of giant panda species has basically eaten bamboo and other plants, indicating that giant pandas were vegetarians as early as 2 million years ago.
So what did the giant panda look like earlier? Many bears that once lived in the Miocene and Pliocene in Eurasia and North America were once regarded as having a more direct relationship with the giant panda, but they were abandoned because they had few common features with the giant panda, or because they had too little fossil evidence to be convincing.
Chinese paleontologists found some sporadic tooth fossils in the brown coal seam distributed in Lufeng, Yunnan Province. From the morphology and structure of the occlusal surface of these teeth, the tooth owner already has some corresponding characteristics of the living giant panda. Therefore, they named the tooth owner Shi panda, which is the earliest known ancestor of giant panda in the world, and affirmed the genetic relationship between giant panda and Ursidae. Before that, a small number of suburban panda tooth fossils were also found in the brown coal seam in Europe and Hungary, which was later than the original panda in age. However, the suburban panda has no offspring, so it is difficult to judge whether it is also the ancestor of the living giant panda.
To be sure, it is an extinct collateral branch of the giant panda. It can be seen from fossils that giant pandas were distributed in Europe and Asia in the late Miocene, and the limitation of the distribution of living giant pandas should begin in the Pliocene. Both Shi panda and suburban panda come from lignite seam. It can be seen that they live in swamp, so they can't feed on bamboo. So when did giant pandas start eating bamboo? Why should we eat bamboo instead? These remain mysteries.