Let's get acquainted today with one of the most calm representatives of the crocodiles - the Chinese alligator.
Chinese Alligator
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. Females are roughly three-quarters the length of males. 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. Reports are known of alligators in China reaching 3.0 metres (10 ft) 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, including its belly. 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.
The habitat of the Chinese alligator is bodies of fresh water, particularly wetlands and ponds, in areas transitioning between subtropical and temperate climates. It lives at the base of mountains, in areas where grass and shrubs are common. 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.
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, mussels, and snails. When possible, it eats rodents 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.
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. Although these bellows occur most frequently during the mating season, adults also bellow throughout the rest of the year.
Young Chinese alligators often communicate with each other and their parents using vocal signals to "maintain group cohesion". Young also make sounds when in danger, which alert adults to help and caution nearby young of the threat. Embryos produce distinctive sounds 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.
Distribution
The range of the Chinese alligator is extremely restricted; as of 2015, the only places it is confirmed to live in the wild are Xuancheng, Nanling County, Jing County, Wuhu, Langxi County, and Guangde County – six counties and cities in the province of Anhui, occupying a total area of about 5 square kilometres (1.9 sq mi). It has been reported to rarely occur in the provinces of Jiangsu and Zhejiang, but it is unknown whether it still lives there. It is the only species in the family Alligatoridae that lives on a continent other than North or South America.
Conservation
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. In the 1950s, the alligator was 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, at which time the population was about 1,000.
In 1998, the population of the Chinese alligator was the lowest it had ever been; the largest area it lived in was a small pond along the Yangtze surrounded by farmland, which held 11 alligators. In 1999, the Wildlife Conservation Society estimated that 130–150 individuals were left in the wild. 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. 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. The survey reasoned that the species' population was growing in four sites, but stable in the rest of the alligator's range. A 2012 journal article estimated the population at the time to be 120–150. 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. Wang Renping, the head of the ANNRCA, stated in 2017 that about 300 specimens existed in the wild, some of which had been born captive and reintroduced to the wild. As of 2018 the population is not considered to be further declining.
In its native country, the Chinese alligator has been listed as a Class I endangered species since 1972, which gives it the highest possible degree of legal protection and makes killing or capturing the species in the wild forbidden. It is listed as a CITES Appendix I species 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.
That's it for today. See you all next time.
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