Chinese Alligator

The Chinese alligator (Alligator sinensis) (simplified Chinese: 扬子鳄; traditional Chinese: 揚子鱷, yáng zǐ è), also known as the Yangtze alligator, China alligator, or historically the muddy dragon, is a critically endangered crocodilian endemic to China. The American alligator and it are the two living species in Alligator, a genus in 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 the winter and is nocturnal in the summer. Mating occurs in the early summer, with females most commonly producing 20–30 eggs, which are smaller than any other crocodilian. The species lives to age 50 on average, although some captive specimens have reached age 70. It 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.

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Explanation

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Chinese alligator
Temporal range: Pliocene – recent
[1]
A Chinese alligator in short grass
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Crocodilia
Family: Alligatoridae
Genus: Alligator
Species:
A. sinensis
Binomial name
Alligator sinensis
(Fauvel, 1879)
Synonyms

The Chinese alligator (Alligator sinensis) (simplified Chinese: 扬子鳄; traditional Chinese: 揚子鱷, yáng zǐ è), also known as the Yangtze alligator,[4] China alligator,[2] or historically the muddy dragon,[5] is a critically endangered crocodilian endemic to China. The American alligator and it are the two living species in Alligator, a genus in 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 the winter and is nocturnal in the summer. Mating occurs in the early summer, with females most commonly producing 20–30 eggs, which are smaller than any other crocodilian. The species lives to age 50 on average, although some captive specimens have reached age 70. It 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.

Living mostly in bodies of fresh water, the Chinese alligator's distribution range is restricted to six regions in the province of Anhui as of 2015. Originally living as far away from its current range as Japan, the species previously had a wide range and population, but beginning in 5000 BC, multiple threats caused the species' population and range to decline. The population in the wild was about 1000 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 (IUCN), multiple conservation actions have been taking place for this species. Several breeding facilities, both in China and foreign countries, have bred specimens in captivity and sometimes released them back into the wild.

The Chinese alligator has been a part of Chinese literature since the third century. In the late 1200s, Marco Polo became the first person outside of China to write about it. In many writings, the Chinese alligator has been associated with the Chinese dragon. Biologists John Thorbjarnarson and Xiaoming Wang have studied the relationship between the alligator and the mythological creature. Many pieces of evidence suggest that the Chinese alligator was the inspiration for the Chinese dragon.

History and taxonomy

Chinese alligators have appeared in Chinese literature since 222–227 AD.[6] Marco Polo was the first person outside of China to write about the alligator, when he came to China and discovered it in the late 1200s.[7] 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, M. Martini, a priest, wrote about the Chinese alligator in a book. The book said that it lived in the river Yangtze and was "much feared by the local residents".[8] Unlike Polo, Martini wrote his description using information from Chinese literature.[6] Chinese alligators were later thought to give priests merit if the priests were to buy alligators held in captivity and release them.[8] 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.[6]

The alligator was described by French naturalist Albert-Auguste Fauvel in 1879, as Alligator sinensis.[8] The genus Alligator had previously contained only the American alligator since its creation in 1807.[9] Fauvel wrote a detailed description of the species in a book titled Alligators in China: Their History, Description & Identification,[10] including information about its historical account.[6] 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 was developed as an offshoot of other now-extinct animals in the genus Alligator. This and the fact that the American alligator does infrequently have a bony plate on its eyelid has caused Caigator sinensis to now be classified as a synonym of Alligator sinensis.[8]

The genus, Alligator, is based on the Spanish word el lagarto, which translates to "the lizard". The specific name, sinensis, is from the Latin plural possessive sinaensis, meaning "belonging to China".[11]

Description

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)
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 1.5–2.1 metres (5–7 ft) and weight of 36–45 kilograms (80–100 lb) as an adult.[5] Females are roughly three-quarters the length of males.[12] It is less than half the size of the American alligator, which typically grows to a length of 3.4 metres (11.2 ft) for males and 2.5 metres (8.2 ft) for females.[13] Reports are known of alligators in China reaching 3.0 metres (10 ft) in past centuries, but these are thought to no longer be accurate.[11]

The Chinese alligator is almost completely black or dark gray in color as an adult.[12] It has a short and broad snout,[14] which points slightly upwards and narrows at the end. Its head is robust, more so than that of the American alligator,[15] with a bony septum dividing its nostrils.[14] It has 72–76 teeth, of which 13–14 are maxillary, five are premaxillary, and 18–19 are mandibular.[11] Unlike the American alligator, the Chinese alligator is fully armored,[5] including its belly.[16] It contains up to 17 rows of scales across its body, which are soft on its belly and the side of its body, and rougher on its back. Its upper eyelids have bony plates on them, a feature usually not present in the American alligator.[8] Its tail is wider than that of the American alligator[14] and has a ridge-like formation at the end of it where its scales intersect.[17] It does not have webbed feet, in contrast to the American alligator, which has extensive webbing on its toes.[14]

Behavior

The Chinese alligator is dormant in burrows during the winter. After its dormancy, it frequently spends time in the sun before summer begins.[15] It is nocturnal throughout the summer, feeding at night and sheltering in the daytime, to avoid both humans and the summer heat.[16] This behavior gives it the ability to live in areas where humans are common.[2] A docile species, it does not intentionally hurt humans outside of potential extreme circumstances.[5]

Burrowing

The Chinese alligator brumates[15] in its burrows from late October to mid April, emerging in early May. It constructs these burrows next to ponds and other small bodies of water, using its head and front legs to dig into the ground.[12] The burrows can be large and complex, containing multiple rooms, water pools, and entrances.[16] Most of them are 10–25 metres (33–82 ft) long, with each room containing enough space for alligators to turn around after entering. Outside of winter, the burrows serve as retreat sites for the alligators[12] and in the summer are where the alligators take shelter in the daytime.[16] Inside the burrows, the temperature is never colder than 10 °C (50 °F).[11] The burrows can be problematic for farmers, as they cause drainage problems in fields.[17]

Life cycle

A baby Chinese alligator on a mass of vegetation in a body of water
Young alligators, such as this one, are covered with light spots.

The breeding season of the Chinese alligator is the early summer. The species exhibits polygamy, with males able to mate with multiple females per season. During the time of mating, both male and female specimens are often aggressive to each other.[16] The rate of mating is the highest in the middle of June; during this time, males commonly search around many ponds to find a mate.[12] It often exhibits multiple paternity, meaning that an egg clutch produced by a female can be fertilized by multiple males. A study of 50 clutches showed multiple paternity in 60% of them, with three being the maximum number of contributing males.[18] Nests are typically built about 2–3 weeks after mating,[16] during the later part of the summer, from July to late August.[2] Constructed by the females, they are composed of rotting plants, such as leaves, and have a height of 40–70 centimetres (16–28 in). They are always built near water sources, and if possible, on islands so they are disturbed less often by people.[19]

Generally laid at night,[20] mating typically produces 20–30 eggs,[21] although according to the IUCN, the alligator has the capability of laying 10–40 eggs.[2] After the eggs are laid, the females sometimes leave the nest, but other times stay to protect the eggs.[20] The eggs are about 6 centimetres (2.4 in) in length, 3.5 centimetres (1.38 in) in diameter, and 45 grams (1.59 oz) in weight, making them smaller than the eggs of any other crocodilian.[21] They are typically incubated for about 70 days.[11] Hatched in September, the temperature of incubation controls whether a young alligator will be male or female, a feature present in all crocodilians.[19] Mothers assist the hatching of young and help them leave the nest and bring them to the water after hatching.[15]

Newborn alligators, like their eggs, are the smallest of any crocodilian, with a length of 20–22 centimetres (7.87–8.66 in) and weight of 25–30 grams (0.88–1.06 oz).[22] Unlike adults, they have light speckles on their bodies and heads.[12] They grow very little in their first year, due to being able to feed for only about 2 months after hatching before the winter. They depend on their mothers to protect them during their first winter, as their small size makes them an easy prey target.[22] A large amount of Chinese alligator clutches have multiple paternity, meaning that they are raised by several males. In the fall and winter, young eat very little, causing a dramatic decrease in growth rate and a decrease in weight. A study published in the journal Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology showed that the Chinese alligator is two-thirds the length of the American alligator and one-half its weight at birth, but is one-half its length and one-tenth its weight after one year.[23]

According to the National Zoological Park, females reach maturity roughly four to five years after birth,[16] although other sources estimate that they mature at age six to seven.[19] A lifespan of 50 years is typical in the wild; it was previously believed to only be able to live into its 50s, but some specimens in captivity have reached age 70. It is able to breed in its 50s, although it cannot when any older.[24]

Feeding

The Chinese alligator is an opportunistic feeder, meaning that it can prey on a variety of different animals depending on what is available. It is a carnivore, mostly eating fish and invertebrates, such as crustaceans, insects, and snails, and when possible, it eats rodents and aquatic birds, as well.[16] Similarly, its American relative preys on birds, fish, frogs, mammals, and invertebrates.[13] The Chinese alligator has dull teeth, which allow it to eat prey with shells more easily.[5] A detailed study of the alligator's diet in 1985 showed that snails were by far the most common animal in its diet at 63%, with 41% of its total diet being river snails and 22% 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.[19]

Vocalization

The Chinese alligator is a very vocal species, making many different sounds in multiple situations.[25] 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. This may occur as a way for mating groups to gather together rather than a mating competition.[26] According to the Journal of Experimental Biology, 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 larger males. Although these bellows occur most frequently during the mating season, adults also bellow throughout the rest of the year.[27]

Young Chinese alligators often communicate with each other and their parents using vocal signals to "maintain group cohesion".[25] Young also make sounds when in danger, which alert adults to help and caution other young nearby of the threat. Embryos produce distinctive sounds when inside their eggs, which alert the adult female that the nest is ready to be opened. These vocalizations are high-pitched, while their danger calls are louder.[25]

Distribution and habitat

The Chinese alligator in water, mostly submerged
The habitat of the Chinese alligator is fresh water bodies, as pictured.

The Chinese alligator lives in bodies of fresh water,[2] inhabiting "the area of climatic transition between subtropical and temperate regions".[12] Occurring at the base of mountains, it lives in areas where grass and shrubs are common.[20] It was once abundant in wetlands and other larger bodies of water in the wild, such as rivers and lakes, but loss of habitat has limited it to primarily ponds and drainage ditches.[15] Habitat loss has also forced it to live at higher elevations than it prefers, where the weather is colder and the soil is unfit for burrow digging. In one study of the alligator, crocodilian conservationist John Thorbjarnarson observed a female that had to build her nest of pine needles rather than the usual plants; the eggs in the nest died due to the pine needles not being able to warm the eggs properly.[28] Its range is extremely restricted; as of 2015, the only places it lives in the wild are Xuancheng, Nanling County, Jing County, Wuhu, Langxi County, and Guangde County – six counties and cities in the province of Anhui.[20] It is the only species in the family Alligatoridae that lives on a continent other than North or South America.[16]

Population and range trend

The oldest record of the Chinese alligator is a skeleton fragment found in western Japan. The fossil is estimated to be from 3 million years ago (Mya), in the late Pliocene period. The skeleton showed that the species was larger at the time than it is currently, with a total length of at least 200 centimetres (79 in). According to the Journal of Asian Earth Sciences, alligators are believed to have moved into various parts of Japan either before 25 Mya or after 10 Mya and were extirpated from there during the Plio-Pleistocene period, due to tectonic changes and the country's poor climate.[1]

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.[29] 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.[28] In the 1700s, much of the Chinese alligator's habitat was replaced with farming fields on after a large number of people had moved into the area.[30] By the 20th century, its range was reduced to a few small areas around the Yangtze.[29] In the 1950s, the alligator was found in three distinct areas: the southern area of the Yangtze (Chang Jiang) from Pengze to the western shore of Lake Tai (Tai Hu), the mountainous regions of southern Anhui, and the provinces of Jiangsu and Zhejiang, primarily in lakes, streams, and marshes. By the 1970s, it was restricted to small parts of southern Anhui and Zhejiang,[31] at which time the population was about 1,000.[2]

In 1998, the population of the Chinese alligator was the lowest it had been; the largest area it lived in was a small pond along the Yangtze surrounded by farmland, which held 11 alligators.[32] In 1999, the Wildlife Conservation Society estimated that 130–150 individuals were left in the wild.[17] According to The New York Times, the population was less than 130 in 2001; at this time, alligators sometimes wandered around to look for a suitable habitat, but were unsuccessful due to their habitat having been turned into rice fields.[28] In 2003, the population began to gradually increase after having been roughly stable between 1998 and 2003. A survey of the population by the Anhui National Nature Reserve for Chinese Alligator (ANNRCA) in 2005 deduced that between 92 and 114 adults and 66 young remained in the wild.[33] The survey reasoned that the species' population was growing in four sites, but staying roughly the same in all other areas where the alligator lived.[2] An article published by the Journal of Genetics in 2012 estimated the population at the time to be 120–150,[34] and a survey in 2015 indicated that roughly 136–173 alligators remained in the wild.[2] According to Wang Renping, the head of the ANNRCA, about 300 specimens were in the wild in 2017, of which some had been born captive and reintroduced to the wild.[33]

Reasons for population decline

Refer to caption
A Chinese alligator among a field of grass and a small body of water

Considered to be one of the most endangered crocodilian in the world, the Chinese alligator's biggest threats in the late 20th century were human killing and habitat loss.[2] A majority of the species' wetland habitats were destroyed to construct rice paddies,[28] as well as to construct dams.[35] During the 1970s and 1980s, humans sometimes killed the alligators, because they believed they were pests, out of fear, or for their meat.[32] Thought to have the ability to cure colds and prevent cancer,[5][35] the organs of the Chinese alligator were sometimes sold for medicinal purposes.[11] In several restaurants and food centers in China's more prosperous areas, young alligators were allowed to roam free with their mouths taped shut, and were subsequently killed for human consumption,[36] served as a dish with rice, vegetables, and chopped up alligator flesh.[28] In the late 20th century, people living in the range of the Chinese alligator ate its meat due to believing that it was "dragon meat".[30]

The Yangtze was flooded in the winter of 1957, which is believed to have caused many Chinese alligators to drown.[30] Rats, which the Chinese alligators eat, have been poisoned by farmers, so are also a cause for the diminishing of the species.[5] The organochlorine compound sodium pentachlorophenate was used to kill snails in agricultural fields starting in 1958 and incidentally poisoned the alligators, as well.[30] Other factors that led to the endangerment of the alligator include natural disasters and geographic separation.[2] In addition to outside threats, Chinese alligators seldom reproduce in the wild, which has contributed to the species' population decline.[28]

Status and conservation

The Chinese alligator is listed as a Class I endangered species as of 1972, which gives it the highest possible degree of legal protection and makes killing or capturing the species in the wild forbidden.[2] It is listed as a CITES Appendix I species on China's Protection List.[20] Following six previous assessments as endangered from 1982–1994, it is classified as critically endangered on the IUCN Red List as of 1996.[2][29] In 1982, the Anhui National Nature Reserve for Chinese Alligator (ANNRCA) was created, a reserve spanning across the entire distribution range of the Chinese alligator,[20] now covering an area of 18,565 hectares (45,880 acres).[2]

In captivity

Two Chinese alligators among rocks
Chinese alligators at Shanghai Zoo

At least 20,000 Chinese alligators[lower-alpha 1] are living in captivity due to captive-breeding programs, the first initiated in the 1970s.[37] Captive-born Chinese alligators have been reintroduced into their native range, boosting the wild population.[38] The individuals of these releases have adapted well to a life in the wild and have bred. As of 2016, the largest group of Chinese alligators that have been released in the wild was when 18 specimens were reintroduced to Langxi, part of the species' native habitat, on May 22, 2016.[4]

China

The two largest breeding centers for the Chinese alligator are located in, or near, the areas where Chinese alligators are still found in the wild. With roughly 15,000 Chinese alligators in captivity as of 2016, the Anhui Research Center for Chinese Alligator Reproduction (ARCCAR) is the largest of them.[2] The center is located 5 kilometres (3.1 mi) from the city of Xuancheng (30°54′30″N 118°46′20″E / 30.90833°N 118.77222°E / 30.90833; 118.77222),[19] where it makes use of a series of ponds in a small valley.[39] Founded in 1979, the ARCCAR was stocked with 212 alligators[33] collected from the wild over the first decade after its establishment,[40] and received alligator eggs collected by the area's residents or the ARCCAR's own staff in the nests of wild alligators as well.[41] In 1988, the first eggs by human-bred alligators were laid. The reserve decided to reintroduce some of its alligators in the wild in 2001, which was carried out in 2003 when three alligators were released.[33] The alligator breeding was so successful that the ARCCAR began to use the alligators for local meat consumption and live animals for the European pet market, with the profits from these activities continuing to fund the breeding centers.[42]

The other major breeding center for the species is the Changxing Chinese Alligator Nature Reserve (CCANR)[2] or Changxing Nature Reserve and Breeding Center for Chinese Alligators (CNRBRCCA),[43] located in Changxing County, Zhejiang, about 92 kilometres (57 mi) east of the ARCCAR (30°55′15″N 119°44′00″E / 30.92083°N 119.73333°E / 30.92083; 119.73333). Originally known as Yinjiabian Alligator Conservation Area (尹家边扬子鳄保护区), the breeding center was established in 1982.[42][44] Unlike ARCCAR, where alligator eggs are collected by the center's staff for incubation in controlled condition, the CCANR allows eggs to hatch naturally.[39] According to a 2013 official report,[45] 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),[43] and by 2016 5,500 specimens were housed there.[2]

In 2003, the ARCCAR received a donation of $1.2 million from the State Forestry and Grassland Administration of China (SFGA) and $0.74 million from the government of Anhui. This allowed the organization to improve the conditions of the specimens they were holding in captivity by creating two breeding areas to hold the alligators, which are 1.6 hectares (4.0 acres) each, as well as heightening the fence they had previously built. The CCANR received a donation of $0.6 million from the SFGA and $0.8 million from the government of Changxing, enabling it to reinstate wetlands for the alligators and enhance the facilities of the organization.[2] Both the ARCCAR and the CCANR position themselves as tourist attractions, where paying visitors can view alligators and learn about them.[46]

Multiple other breeding facilities that house the Chinese alligator exist in various provinces of China, as well as private breeding farms and museums.[2]

Foreign countries

The Chinese alligator's head and front part of body among grass next to water
The Chinese alligator in the Smithsonian National Zoological Park

Although by far the largest numbers of captive Chinese alligators are at centers in its native country, the species is also kept and bred at many zoos and aquariums in North America and Europe. Some individuals bred there have been returned to China for reintroduction to the wild.[38] The first time the alligators were ever transported internationally is believed to have been when several were taken from China to the United States in the 1950s. In November 2017, four Chinese alligators were transported to Shizuoka, Japan, which was the first time since 2006 any individuals of the species were taken to another country.[33]

Among the North American zoos and aquariums keeping this species are the Bronx Zoo,[47] Cincinnati Zoo,[38] Philadelphia Zoo,[48] San Diego Zoo,[5] Santa Barbara Zoo,[49] Smithsonian National Zoological Park,[16] and St. Louis Zoo.[15] In Europe, about 25 zoos and aquariums keep the species, such as the Barcelona Zoo (Spain), Bioparco di Roma (Italy), Crocodile Zoo (Denmark), Moscow Zoo (Russia), Pairi Daiza (Belgium), Paradise Wildlife Park (England), Parken Zoo (Sweden), Prague Zoo (Czech Republic), Tallinn Zoo (Estonia), Tierpark Berlin (Germany), and Wildlands Adventure Zoo Emmen (Netherlands).[50]

Chinese dragon association

3D artwork of the Chinese dragon on a wall
The Chinese dragon in Haikou, Hainan, China

Some writers have associated the Chinese alligator with the Chinese dragon.[15] The alligator is thought to have been the inspiration for it.[51] The theory that the Chinese dragon was a mythological version of the Chinese alligator was widespread in the early 1900s, with the idea having later been revisited by John Thorbjarnarson and Xiaoming Wang.[52] According to The New York Times, the association with the "beneficent" mythological creature is an advantage for the species.[28]

Unlike dragons in myths of the Western Hemisphere, Chinese myths portray its dragon as a symbol of "royal power and good fortune", frequently helping and saving people. The Chinese dragon is able to fly and swim;[28] however, unlike dragons in the Western Hemisphere, it does not have wings. The relatively harmless nature of the Chinese alligator is believed to have been an influence for the helpful nature of the dragon.[51] The fact that the alligator ends its hibernation when the rainy season begins and returns to its burrows when the rainwater in rivers recedes, as well as the fact that it lives in bodies of water, may be the reason for the dragon's portrayal as a water-related mythological creature.[51][52] Alligator drums may have been used to simulate the species' vocalizations during the mating season, which humans associated with the dragon's "power of summoning rainclouds".[52] Tu long, which was previously a common name of the Chinese dragon in China, translates to "earth dragon" in English.[28][52]

See also

Notes

  1. Over 15,000 in the Anhui Research Center for Chinese Alligator Reproduction (ARCCAR) and 5,500 in the Changxing Nature Reserve and Breeding Center for Chinese Alligators (CNRBRCCA), as well as those living in other smaller facilities

References

  1. 1 2 Iijima, Masaya; Takahashi, Keiichi; Kobayashi, Yoshitsugu (2016). "The oldest record of Alligator sinensis from the Late Pliocene of Western Japan, and its biogeographic implication". Journal of Asian Earth Sciences. 124: 94–101. Bibcode:2016JAESc.124...94I. doi:10.1016/j.jseaes.2016.04.017.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Crocodile Specialist Group (1996). "Alligator sinensis". IUCN Red List of Threatened Species. 1996: e.T867A13086708. doi:10.2305/IUCN.UK.1996.RLTS.T867A13086708.en.
  3. Wu, Ziaobang; Zhou, Kaiya; Wang, Yiquan; Zhu, Weiquan (October 2003). "Complete mitochondrial DNA sequence of Chinese alligator, Alligator sinensis, and phylogeny of crocodiles". Chinese Science Bulletin. 48 (19): 2050–2054. Bibcode:2003ChSBu..48.2050W. doi:10.1360/03wc0076. Retrieved 20 December 2018.
  4. 1 2 "The largest group of Chinese alligators released to the wild". UNDP in China. June 8, 2016. Retrieved April 23, 2017.
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  6. 1 2 3 4 Barbour, Thomas (April–September 1910). "A Note regarding the Chinese Alligator". Proceedings of the Academy of Natural Sciences of Philadelphia. 62: 464–467. Retrieved 6 January 2019.
  7. Thorbjarnarson & Wang 2010, p. 34.
  8. 1 2 3 4 5 Neill 1971, pp. 293–294.
  9. "Alligator". Integrated Taxonomic Information System. Retrieved 25 January 2019.
  10. Fauvel 1879, p. 33.
  11. 1 2 3 4 5 6 "Chinese Alligator (Alligator sinensis)". Crocodilians: Natural History & Conservation. Retrieved January 2, 2012.
  12. 1 2 3 4 5 6 7 Reading & Miller 2000, p. 72.
  13. 1 2 "American alligator". Smithsonian's National Zoo. April 25, 2016. Retrieved December 12, 2018.
  14. 1 2 3 4 Grigg 2015, p. 6.
  15. 1 2 3 4 5 6 7 "Chinese Alligator". Saint Louis Zoo. Retrieved December 10, 2018.
  16. 1 2 3 4 5 6 7 8 9 10 "Chinese alligator". Smithsonian's National Zoo. April 25, 2016. Retrieved December 9, 2018.
  17. 1 2 3 "Alligator sinensis". Arkive.org. Archived from the original on October 11, 2016. Retrieved September 26, 2016.
  18. Wang, Huan; Yan, Peng; Zhang, Shengzhou; Sun, Long; Ren, Min; Xue, Hui; Zhang, Fang; Wu, Rong; Wu, Xiaobing (December 2017). "Multiple paternity: A compensation mechanism of the Chinese alligator for inbreeding". Animal Reproduction Science. 187: 124–132. doi:10.1016/j.anireprosci.2017.10.016.
  19. 1 2 3 4 5 Reading & Miller 2000, p. 73.
  20. 1 2 3 4 5 6 Zhang, Fang; Messenger, Kevin; Wang, Yong (2015). "Relationship between nest defence behaviours and reproductive benefits in Chinese alligators". Amphibia-Reptilia. 36 (2): 141–147. doi:10.1163/15685381-00002990.
  21. 1 2 Thorbjarnarson & Wang 2010, p. 121.
  22. 1 2 Thorbjarnarson & Wang 2010, p. 97.
  23. Herbert, J. D.; Coulson, T. D.; Coulson, R. A. (April 2002). "Growth rates of Chinese and American alligators". Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 131 (4): 909–916. doi:10.1016/S1095-6433(02)00027-2.
  24. Grzimek 2003, pp. 173–176.
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