The Chinese alligator (; ), also known as the Yangtze alligator (), China alligator, 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 in length and weighs 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.
History and taxonomy
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. 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.
The evolutionary relationships of alligators can be shown in the cladogram below:
Etymology
The genus, Alligator, is based on the Spanish word . The specific name, sinensis, is from the Latin plural possessive , meaning "belonging to China".
Description
thumb|left|alt=A black and white image of the American alligator and the Chinese alligator next to each other|Comparison of the American alligator (top) and the Chinese alligator (bottom)
thumb|left|alt=An up-close view of the left side of the Chinese alligator's head|Detail of head
One of the smallest species of crocodilians, the Chinese alligator attains a length of and weight of as an adult. Reports are known of alligators in China reaching in past centuries, but these are no longer thought to be accurate.
The Chinese alligator is almost completely black or dark gray in color as an adult. It has a short and broad snout, which points slightly upwards and narrows at the end. Its head is robust, more so than that of the American alligator, with a bony septum dividing its nostrils. It has 72–76 teeth, of which 13–14 are maxillary, five premaxillary, and 18–19 mandibular. Unlike the American alligator, the Chinese alligator is fully armored, It contains up to 17 rows of scales across its body, which are soft on its belly and side and rougher on its back. Its upper eyelids have bony plates on them, a feature usually not present in the American alligator. Its tail is wider than that of the American alligator. It does not have webbed feet, in contrast to the American alligator, which has extensive webbing on its toes.
Ecology
The Chinese alligator brumates in burrows during winter. During the time of mating, males commonly search around ponds to find a mate and both male and female specimens are often aggressive to each other. Nests are typically built about 2–3 weeks after mating, Nests are always near water sources. Individuals often return to the same nesting site yearly, although intraspecific competition and environmental changes can force them to change nesting sites. mating typically produces 20–30 eggs, although according to the International Union for Conservation of Nature (IUCN), clutch size ranges between 10 and 40 eggs. This temperature controls whether a young alligator will be male or female (temperature-dependent sex determination), a feature present in many other reptiles. A higher incubation temperature also increases the hatching rate. Young depend on their mothers to protect them during their first winter, as their small size makes them an easy prey target.
The alligator grows quickly in its first few years, with its growth rate slowing at age five. According to the National Zoological Park, females reach maturity roughly four to five years after birth, When possible, it eats rodents, other small mammals, and aquatic birds as well. It has dull teeth, which allow it to eat prey with shells more easily. A study of the alligator in 1985 showed that snails were the most common animal in its diet at 63%, with 65% of that being river snails and 35% spiral-shelled snails. According to the survey, its diet also contained 16% rabbits, 8.3% mollusks, and 4.1% shrimp, with the remaining 6.8% being frogs, fish, and insects.
Vocalization
The Chinese alligator is a vocal species, making many different sounds in multiple situations. When communicating with nearby alligators, it produces sounds such as head slapping, hissing, and whining, which have a low sound pressure level (SPL). To communicate long-distance, it produces bellows, which have a high SPL. All of these sounds have a low frequency of less than 500 hertz, due to the alligator's densely vegetated habitat, which allow the sounds to spread across a greater area.
Both sexes participate in bellowing choruses during the mating season as adults. Lasting an average of 10 minutes, the alligators remain still for the entirety of the chorus, with both sexes responding equally in rough unison. The main purpose of these bellows is to call out to alligator specimens to collect at a specific pond, where individuals choose mates and engage in copulation. Alligators may also bellow to publicize their size, a behavior which occurs in multiple other vertebrates. The size of a specimen is a significant factor for mating; females only mate with males larger than themselves. Bellowing is most common at 6:00–7:00 am and 11:00–12:00 am CST.
The population of the Chinese alligator began to decline in 5000 BC, when human civilization started to grow in China, after having been very abundant in the lower Yangtze area. This area was one of the first places in the world to farm rice, causing much of the alligator's habitat to be destroyed in favor of rice farms. In the 1700s, much of the Chinese alligator's habitat was replaced with farming fields after a large number of people had moved into the area. By the 20th century, its range was reduced to a few small areas around the Yangtze. at which time the population was about 1,000. In 1999, the Wildlife Conservation Society estimated that 130–150 individuals were left in the wild. A 2015 survey observed 64 individuals, of which 32 were adults, estimating that the total number of adults was 68–86 and the total population 136–173. As of 2018 the population is not considered to be further declining.
Reasons for population decline
Considered to be one of the most endangered crocodilians in the world, During the 1970s and 1980s, humans sometimes killed the alligators, because they believed they were pests, out of fear, or for their meat. served as a dish of rice, vegetables, and chopped up alligator flesh. and an endangered species by the U.S. Fish & Wildlife Service. Following six assessments as endangered from 1982 to 1994, it is classified as critically endangered on the IUCN Red List as of 2017. Six specimens were released from captivity in 2007, followed by six more in June 2015. As of June 2016, the largest group of Chinese alligators to have been released in the wild was when 18 specimens were reintroduced to Langxi County, part of the species' native habitat, on May 22, 2016. These releases have proven successful, with individuals adapting well to a life in the wild and breeding. in Changxing County, Zhejiang, about east of the ARCCAR. Originally known as the Yinjiabian Alligator Conservation Area (尹家边扬子鳄保护区), the breeding center was established in 1982. Unlike the ARCCAR, where alligator eggs are collected by the center's staff for incubation in controlled condition, the CCANR allows eggs to hatch naturally. According to a 2013 official report, the CCANR housed almost 4,000 alligators, including 2,089 young (1–3 years old), 1,598 juveniles (4–12 years old), and 248 adults (13+ years old). Cincinnati Zoo, San Diego Zoo, St. Augustine Alligator Farm Zoological Park, Smithsonian National Zoological Park,
Chinese dragon association
right|thumb|alt=3D artwork of the Chinese dragon on a wall|The Chinese dragon in [[Haikou, Hainan, China]]
Some writers have suggested that the Chinese alligator was the inspiration for the Chinese dragon.