Searching for dragons in the Year of the Dragon: Did the "hidden dragon" in Lingnan described by Han Yu really "transform into a dragon"?

The Spring Festival is getting closer! This year is the Year of the Dragon. Among the twelve zodiac signs, if there is one that best reflects the rich imagination of our Chinese nation, it must be the dragon. In the impression of many people, the dragon is a fictional creature that does not exist in the real world. However, this does not mean that the prototype of the dragon does not exist. In the land of China, there were many creatures that "had the appearance of a dragon".

01 Alligator: The cutest crocodile among alligators - the Yangtze Alligator

The Yangtze alligator, which still lives in the wetlands of the middle and lower reaches of the Yangtze River in my country, has a "dragon-like" appearance. This reptile covered in hard "armor" was called "crocodile dragon" by the ancients, that is, the ancients believed it to be a kind of dragon. Analyzing the living habits of the Yangtze alligator from the perspective of modern biology, it is not entirely unreasonable for the ancients to believe it was a dragon.

Early summer is the breeding season for alligators. Male alligators gather in groups on the water, raise their heads to the sky and roar loudly like beating drums. This happens to be the rainy season in the middle and lower reaches of the Yangtze River . The roar on a rainy day is a scene that reminds people of the dragon in myths and legends that can "call the wind and rain".

However, the total length of an adult Chinese alligator is generally only 1.5-2.1 meters, and the largest is no more than 2.46 meters . Therefore, it is relatively "petite" in appearance, and compared with the majestic and awe-inspiring dragons in paintings and sculptures, it seems more simple and cute, but not majestic and domineering.

Figure 1: Swimming Chinese alligator (copyright image from the gallery, reprinting may cause copyright disputes)

Looking around the world, many members of the existing Crocodile Order, such as the Nile crocodile in Africa, the saltwater crocodile in Southeast Asia and Australia, and the American crocodile in Central and South America ... These large crocodiles have huge bodies, with a maximum body length of more than 5 meters. The largest saltwater crocodile can even be more than 6 meters long . With its invulnerable hard endoderm and membrane bone plates , powerful bite force , and a mouth full of staggered conical sharp teeth , they are all well-deserved top predators in their ecosystems. They are the "water tyrants" in rivers and lakes, and naturally have more "dragon-like" appearance than the "petite" Yangtze alligator. So, have there ever been large crocodiles with more "dragon-like appearance" in China?

Figure 2: Clockwise from the upper left corner: Saltwater crocodile, Mississippi alligator, and gharial (Source: Wikipedia)

02 The answer lies in the article of the great writer Han Yu

In 1963, people accidentally discovered a huge crocodile skull while digging a fish pond in Shunde District, Guangdong Province (now Foshan City). In the following 17 years, the remains of the same crocodile were discovered in five other places in the Pearl River Delta . Unlike the existing Yangtze alligators in China, this giant crocodile had a slender snout and was once thought to be the skeleton of a Malayan crocodile. The Malayan crocodile belongs to the family Crocodilia, the genus Crocodile of the subfamily Crocodilianae, and still lives in freshwater rivers and swamps in Southeast Asia.

Figure 3: Skull of Chinese crocodile (Source: Wikipedia)

In subsequent studies, scholars at home and abroad began to notice that these crocodile skeletons were somewhat different from the existing Malayan crocodiles, but were somewhat similar to the Alligatorinae (another subfamily of the Alligatoridae, whose only existing member is the Ganges crocodile living in the rivers of South Asia). Eventually, they were confirmed to be a new species of the Alligatoridae that had not yet been described, and in 2022 they were named Chinese Han Yu Crocodile ( Hanyusuchus sinensis ). The genus name commemorates Han Yu, a great writer who served as the governor of Chaozhou and wrote "Sacrifice to the Crocodile" .

Figure 4: Han Yu, a great writer in the Tang Dynasty (Source: Wikipedia)

How could this disappeared giant crocodile be related to the famous Tang Dynasty writer Han Yu? It turns out that the two with cut marks among the six Han Yu crocodile skeletons found so far died between the 14th and 10th centuries BC , which is the Bronze Age . However, from the end of the Eastern Han Dynasty to the Ming Dynasty, ancient Chinese books and documents have recorded the appearance of ferocious crocodiles "as big as boats and with teeth as sharp as saws" in the Lingnan region, even endangering people and animals.

Figure 5: The distribution range of the fossils of Hanyu crocodile in China and the record of the appearance of crocodiles in Lingnan (Source: Wikipedia)

In the 14th year of Yuanhe Period in the Tang Dynasty (819 AD), Han Yu, then Vice Minister of the Ministry of Justice, was demoted to the governor of Chaozhou because of his fierce opposition to Emperor Xianzong of Tang's welcoming of the Buddha's bones. After taking office, Han Yu saw that the local people suffered from crocodiles, so he threw a pig and a sheep into the evil stream where crocodiles were most serious, and made an agreement with the crocodiles living there that after three days, "they will lead their ugly species and migrate south to the sea to avoid the emperor's order. If they fail in three days, they will move on to the fifth day; if they fail in five days, they will move on to the seventh day." If the crocodiles did not move away after seven days, they would be considered "obstinate and unyielding," and Han Yu would organize the local people to kill the crocodiles with strong bows and poisonous arrows.

Of course, crocodiles cannot understand human language, and it is even more impossible for them to migrate to the sea with their families just because of a "Sacrificial Essay to Crocodiles". According to the "Book of the Later Tang Dynasty", Han Yu later organized people to hunt crocodiles and put quicklime, sulfur and other chemicals into the water, which even led to the extinction of local crocodiles for a period of time. The crocodile that Han Yu encountered in Chaozhou is very likely to be the Chinese Han Yu crocodile .

03 The Fierce “Fisherman”

The Chinese crocodile is huge in size. Among the six individuals discovered so far, four are adults, with body lengths ranging from 5.43 to 6.19 meters. The largest skull is 94.5 centimeters long, which is longer than the skull of the largest existing saltwater crocodile .

Unlike the Yangtze alligator, which has a thick and short snout and likes to "crack melon seeds", the Chinese Hanyu crocodile not only has a very slender snout, but also has a large number of densely packed sharp teeth between the upper and lower jaws, and the size of the jaw teeth is not much different . The two existing long-snouted crocodilians: the Malayan crocodile and the Ganges crocodile also have the same body structure, and both crocodilians are experts at fishing: such jaws and teeth are most suitable for quickly sweeping left and right in the water to bite smooth and agile swimming fish . Like the existing long-snouted crocodilians, the Chinese Hanyu crocodile may also be an efficient "fisherman". The large number and variety of fish of various sizes in the freshwater rivers and lakes along the southeast coast of China provide them with a rich source of food .

Figure 6: Body outline of the Chinese crocodile based on the discovered skeletal parts (Source: Wikipedia)

In addition to preying on fish, the existing Malayan crocodiles sometimes prey on larger land mammals such as macaques, deer, and small wild boars. A few large individuals have even been recorded attacking humans. Although the snout of the Hanyu crocodile is relatively slender, its teeth are very large, even larger than those of the Malayan crocodile . In ancient books, there are many records of crocodiles preying on deer, bears, and even tigers in Chaozhou history, devouring livestock raised by locals, and even capsizing boats and injuring people. It can be imagined that at that time, the huge Chinese Hanyu crocodile was a ferocious "dragon" that the fishermen at that time were afraid to avoid.

Figure 7: Reconstruction of the Chinese crocodile (Source: Wikipedia)

According to ancient Chinese classics such as Shuowen Jiezi, Lunheng, and Yunhui, Jiaolong is a fictional aquatic creature classified as a dragon. There is no consensus on the evaluation of this fictional creature. Some regard it as an evil creature, while others regard it as a god. There are many supporters in the academic community of later generations for the view that "the prototype of Jiaolong is the crocodile". So, why did the Chinese Hanyu crocodile, a huge and ferocious "Jiaolong", disappear from our sight? How did it become a "legend" like its "fictional" image - Jiaolong?

04 Suspicious scars: Solving the mystery of "transformation into a dragon"

On the skeletons of many Chinese Hanyu crocodiles, scars left by metal weapons were found. One individual had as many as 17 scars, most of which were concentrated on the crocodile's head. One individual's head was even chopped off by the ancients' sharp blade. These significant scars and the record of "Han Yu killing crocodiles" mentioned above are enough to reflect the intensity of the conflict between humans and crocodiles in Chaozhou, southeastern China at that time . Long-term human hunting, habitat destruction caused by agricultural production, and the cold climate caused by a small ice age in the late Ming Dynasty eventually led to the extinction of the Chinese Hanyu crocodile, a giant crocodile native to China , and the huge and ferocious dragon has since gone from reality to legend forever.

Figure 8: Cut marks on the skull of the Chinese crocodile (Source: Wikipedia)

Today, the small-bodied Yangtze alligator is also declining in population due to habitat destruction, water pollution, illegal fishing and historical mass hunting. In 2001, the number of wild Yangtze alligators in the country once dropped to less than 130, and they were on the verge of extinction. Fortunately, with the unremitting efforts of scientific research and wildlife conservation workers for many years, the artificial breeding technology of Yangtze alligators has become very mature. In 2022, the number of Yangtze alligators released into the wild in Anhui Province alone reached 370 .

The existence of wild alligators is crucial to the wetland ecosystem in the middle and lower reaches of the Yangtze River: they can control the population of some species as predators, and they can also eat and clean up animal carcasses in the water and on land. The habit of digging caves by alligators greatly enhances the ability of wetlands to conserve water, while providing shelter for a wide variety of other wild animals. We hope that these "little alligators" that have accompanied Chinese civilization all the way can thrive again under our attention and protection, continue to swim freely in rivers, lakes and swamps, and continue to write the legendary story of dragons.

Author: Hu Kai, science research instructor, CCTV-9 documentary channel science consultant

Reviewer: Wang Baopeng, Deputy Director and Associate Researcher of the Earth Science Department of the National Museum of Natural History

Produced by: Science Popularization China

Produced by: China Science and Technology Press Co., Ltd., China Science and Technology Publishing House (Beijing) Digital Media Co., Ltd.