The Chinese alligator (Alligator sinensis; simplified Chinese: 鼍; traditional Chinese: 鼉; pinyin: tuó), also known as the Yangtze alligator (simplified Chinese: 扬子鳄; traditional Chinese: 揚子鱷; pinyin: yángzǐ'è), China alligator, or historically the muddy dragon, is a crocodilian endemic to China. It and the American alligator (A. mississippiensis) are the only living species in the genus Alligator of the family Alligatoridae. Dark gray or black in color with a fully armored body, the Chinese alligator grows to 1.5–2.1 metres (5–7 ft) in length and weighs 36–45 kilograms (80–100 lb) as an adult. It brumates in burrows in winter and is nocturnal in summer. Mating occurs in early summer, with females most commonly producing 20–30 eggs, which are smaller than those of any other crocodilian. The species is an opportunistic feeder, primarily eating fish and invertebrates. A vocal species, adults bellow during the mating season and young vocalize to communicate with their parents and other juveniles. Captive specimens have reached age 70, and wild specimens can live past 50.
Living in bodies of fresh water, the Chinese alligator's range is restricted to six regions in the province of Anhui, as well as possibly the provinces of Jiangsu and Zhejiang. Originally living as far away from its current range as Japan, the species previously had a wide range and population, but beginning in 6000 BC, multiple threats, such as habitat destruction, caused the species' population and range to decline. The population in the wild was about 1,000 in the 1970s, decreased to below 130 in 2001, and grew after 2003, with its population being about 300 as of 2017. Listed as critically endangered by the International Union for Conservation of Nature, multiple conservation actions have been taking place for this species.
The Chinese alligator has been a part of Chinese literature since the third century. In the late 13th century, Marco Polo became the first person outside of China to write about it. In some writings, the Chinese alligator has been associated with the Chinese dragon. Many pieces of evidence suggest that the Chinese alligator was an inspiration for the Chinese dragon.
The oldest definitive record of the Chinese alligator is from the late Pliocene of Japan, around 3 million years old. Pleistocene fossils show that its range was once much more extensive, extending northwards to Shandong and southwards to the Taiwan Strait.
Chinese alligators were mentioned in Chinese literature very early; for example, in the Classic of Poetry, whose poems were composed between the 11th and 7th centuries BCE. Marco Polo was the first person outside of China to write about the alligator, when he came to China and saw it in the late 1200s. He said that the alligator lived in "caverns" in the day and hunted at night, and that humans targeted its meat and skin, with its gall bladder having multiple medical purposes. He stated that it was found in lakes, rivers, and springs in the province "Karazan". In 1656, Martino Martini, a priest, wrote that the Chinese alligator lived in the river Yangtze and was "much feared by the local residents". Unlike Polo, Martini wrote his description using information from Chinese literature. Chinese alligators were later thought to give Buddhist priests merit if the priests were to buy alligators held in captivity and release them. In 1869, Robert Swinhoe saw a Chinese alligator in an exhibit in Shanghai and wrote the following year:
In February, 1869, some Chinese were exhibiting in the native city of Shanghai what they called a dragon, which they declared had been dug out of a hole in the province of Shense. It was a young crocodile about four feet long, which they kept in tepid water. They made so much money by showing it that they refused to sell it. I can not, of course, guess its species; but I nevertheless think the fact worth recording, as evidence that a species of this group does occur in China.
The Chinese alligator was scientifically described by French naturalist Albert-Auguste Fauvel in 1879 as Alligator sinensis; though Fauvel only noticed mentions of them in Chinese literature since about 222–227 CE. The genus Alligator had previously contained only the American alligator since its creation in 1807. Fauvel wrote a detailed description of the species in a book titled Alligators in China: Their History, Description & Identification, including information about its historical account. In 1947, it was suggested to group the Chinese alligator in a separate genus from its American relative, due to the Chinese alligator's bony plate on its upper eyelid. This bony plate is present in caimans, but is rarely present in the American alligator. At the time, the plate was thought to not appear in the American alligator at all. This produced the belief that the Chinese alligator's relationship with other crocodilians was between caimans and American alligators. Paulus Edward Pieris Deraniyagala described the genus Caigator the same year, which only contained the Chinese alligator, making its scientific name Caigator sinensis. However, paleontology has shown that the Chinese alligator has evolved from other now-extinct members of the genus Alligator. This and the fact that the American alligator does infrequently have a bony plate on its eyelid have caused Caigator sinensis to now be classified as a synonym of Alligator sinensis. There is still not a consensus among biologists that the American and Chinese alligators belong to the same genus, despite multiple studies comparing the biochemistry, histology, and various other aspects of the two crocodilians.
