Source: Beijing News
Original title: Zhoukoudian "Peking Man" site found cave bear fossils
Previously, there was no clear fossil record of cave bears in China; whether the Zhoukoudian site was a place where "Peking people" lived needs to be further studied
Cave bear skeleton diagram. American Museum of Natural History in September 2018. Courtesy of respondents
Hand-painted reconstruction of the head of a cave bear by Jiang Zuoqigao.
The research on cave bear fossils at the "Beijing Ape Man" site in Zhoukoudian has progressed. Recently, Jiang Zuoqigao, a doctoral student at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, his supervisor Liu Jinyi, Chen Jin of the herbarium, and Jan Wanger of the Czech Academy of Sciences/Czech National Museum, as well as Dong Cuiping, Kui Jianhua and Ning Juan of the Zhoukoudian Museum, collaborated to systematically review the large bear fossils stored in the Institute of Paleovertebrates and the Zhoukoudian Museum, and identified several of the specimens that undoubtedly belonged to the cave bears, and the relevant research was published in the scientific journal Quaternary Science Reviews.
Jiang Zuoqigao said in an exclusive interview with reporters a few days ago that before, most scholars believed that cave bears only existed in Europe, and China has never had a clear and unmistakable fossil record of cave bears. This study has greatly expanded people's understanding of the distribution of cave bears, and also brought new understanding to the study of the "Beijing Ape Man" site in Zhoukoudian.
Find 1
It is proved that the cave bear once lived in the land of China
According to Jiang Zuoqigao, the cave bear Ursus spelaeus (and its ancestral type Denningeri) is a landmark fossil species in Quaternary Europe and one of the earliest fossil species recognized by humans. This giant bear was once found all over Europe and is known for its penchant for inhabiting caves. The fossil chinese cave bear found in this study belongs to ursus deningeri, the denningeri.
"In terms of appearance characteristics, cave bears have 3 basic characteristics: the individual is huge, the forehead is protruding, and the calves are short. These three characteristics correspond to the three habits of cave bears: living in cold areas, mainly plant-based feeding habits, and good at climbing and excavation. Jiang Zuoqigao introduced that cave bears are huge, and some populations of cave bears weigh more than the largest brown bears and polar bears today. Cave bears are very closely related to brown bears and polar bears, and brown bears and cave bears have also crossed in history. Cave bears even have a small amount of genes left in today's brown bears, just as Neanderthal genes remain in modern humans.
Previously, what was the academic community's perception of the cave bear? Jiang Zuoqigao introduced that in the evolutionary history of more than 1 million years, cave bears and ancient humans have carried out countless wars for caves, and finally ended with the complete extinction of cave bears before 17,000 years ago. In the past, most scholars believed that cave bears only lived in Europe, and in recent years some fossils have been found in Russia, but there has never been an unmistakable record of cave bears in China.
"The main significance of this study is to greatly expand the understanding of the distribution of cave bears, proving that cave bears also lived in the land of China." As a result, the cave bear's distribution area spreads throughout the northern part of Eurasia. Jiang Zuoqigao said that at the same time, it was also found that there are certain differences between Chinese cave bears and European cave bears, such as Chinese cave bears with thick metacarpal bones and may be better at excavation, so compared with past cognition, cave bears have higher diversity.
Discover 2
Provide new evidence for Peking Ape Man studies
In addition to the contribution to the evolutionary history of the cave bear, the discovery also brings new understanding to the study of the "Beijing Ape Man" site in Zhoukoudian.
"Cave bears are burrowing bears that spend their winters in hibernation. As a huge bear, the cave bear is probably as grumpy as the 'relative' brown bear, and will never tolerate the disturbance of other large animals in the place where they live. In the era of the Zhoukoudian 'Beijing Ape Man' site, the hunting ability of ancient humans was still relatively low. Jiang Zuoqigao said that if this was once the residence of the cave bear, whether the ancient humans could compete with the cave bear, and whether the ape man site was really the living place of the Beijing people, these questions need to be further studied.
The Cave Bear study also provides new evidence for the study of the age of Beijingers. Jiang Zuoqigao introduced that the cave bear evolved from omnivorous to vegetarian, and its evolution rate was extremely fast, especially the evolution of tooth structure. According to different populations and their epochal counterparts, European scholars can accurate the temporal resolution of cave bear evolution to 100,000-200,000 years. That is to say, every 100,000-200,000 years, the morphological evolutionary accumulation of cave bears has reached a sufficient level that scholars can distinguish the evolutionary stages from the fossil morphology. In this way, the date of formation of the site can be inferred from the morphology of the cave bear.
According to this comparison, the evolutionary level of the Zhoukoudian cave bear is comparable to that of the European MIS17-13 (marine isotope stage, corresponding to 500,000-700,000 years ago). Today's large carnivores, many of which are found on both ends of Eurasia, such as wolves and brown bears, should migrate faster to larger cave bears. Therefore, the age of the Zhoukoudian ape man site is likely to correspond to this time period, that is, between 500,000 and 700,000 years ago. Jiang Zuoqigao said.
■ Dialogue
Jiang Zuoqigao, phD student at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences
Don't expect it at first, "scream out excitedly" when you find out.
Beijing News: What are the main research directions and fields in normal times?
Jiang Zuoqigao: The usual research direction is the evolution of carnivores with the bear family as the core. In addition to the bear family, it also studies the evolution of wolves, badgers and other animals. Zhoukoudian is where the ancient spine of the Chinese Academy of Sciences, where I made my fortune, and although a large number of specimens have been lost after the anti-Japanese war turmoil, it is still the most important fossil research site in China's Quaternary Period.
Beijing News: Before this discovery, what preliminary research work was carried out?
Jiang Zuoqigao: The results of the Dongxiong research were published this time, and the preliminary work was very long. Due to the anti-japanese war, many fossil specimens of Zhoukoudian were lost, and most of them were preserved in wooden boxes and scattered in the warehouse of the Institute, so the collation of Zhoukoudian specimens was the basis for research. When I was a senior, I began to systematically sort out carnivorous fossils with my herbarium teacher, and for more than a year, I sorted out these fossils from the warehouse. It's been 4 years now.
At first, although I hoped to find evidence of cave bears, I did not have any expectations, because the general view in the academic community at that time was that there were no cave bears in China, and I was still influenced by this view, thinking that there may only be brown bears in the Zhoukoudian area.
Tooth fragments reflect typical cave bear features
Beijing News: How was this result found in the end? What was the first reaction at the time?
Jiang Zuoqigao: The first explicit specimen of the cave bear was found when I graduated from my senior year of college, interned in the institute during the summer vacation, and sorted out the specimens in the warehouse. In my senior year, I focused on sorting out the specimens of the underground warehouse and the Xiaotangshan warehouse, and sorted out many fossils of large bears, but none of the specimens showed the characteristics of typical cave bears, in fact, I already felt that there might not be a cave bear in Zhoukoudian. The first specimen found preserved the jaw fragments of three unbrased teeth, and the most easily identifiable feature of the cave bear was in the teeth, and these three teeth were the most recognizable, reflecting the typical characteristics of the cave bear.
I shouted out excitedly at that time, and it can be said that I have fulfilled a long-cherished wish. Later, I continued to sort out and found a set of metacarpal bones, which were obviously thicker than the brown bears in the Zhoukoudian area, and also met the characteristics of cave bears. In retrospect, the most crucial thing is the discovery of the first specimen, which convinced us that there were cave bears in the Zhoukoudian area.
With this belief in mind, we revisited each specimen that had been sorted out, and then I went to the Czech National Museum for further study, specializing in European cave bear specimens, and finally confirmed that several other specimens that were initially uncertain of their attribution also belonged to cave bears.
Last year, I visited Dr. Jan Wagner and their museum's extensive collection of cave bears at the Czech National Museum, where detailed comparative studies confirmed the evolutionary level of the Zhoukoudian cave bears.
The next step will be to study the ecological habits of cave bears
Beijing News: What follow-up research will be carried out after that?
Jiang Zuoqigao: This time, we mainly study the ownership and evolution level of Zhoukoudian cave bears, and then we plan to study the ecological habits of Zhoukoudian cave bears, and determine whether there is a difference between the feeding habits of Zhoukoudian cave bears and European cave bears through tooth abrasion marks. In addition, research on two other bear species, brown bears and black bears, will be gradually published in the Zhoukoudian area.
Beijing News: At present, the public knows less about the field of paleontology, how to enhance everyone's cognition and interest?
Jiang Zuoqigao: At present, the science popularization of paleontology mainly focuses on dinosaurs, so the public knows very little about ancient mammals. To enhance the attractiveness of ancient mammals to the public, it is also necessary to rely more on researchers to publicize and do more science popularization work. Now our new achievements, generally write some special science articles, published in the Institute of Ancient Spine or the Chinese Academy of Sciences WeChat public account. If you are interested, you can search for the public accounts "Institute of Ancient Spine of the Chinese Academy of Sciences" and "Voice of the Chinese Academy of Sciences" to read. (Reporter Zhou Yi)