Chinese alligators are one of the smallest of the crocodilians (a group that includes crocodiles, caimans and gharials) and is amongst the most endangered. The back of its stocky body has a covering of hard scales, with softer scales on the belly and sides. As many as 17 transverse rows with 6 bony scales run the length of its dark green/black body, and there are paired ridges going halfway down its tail, joining into a single ridge that runs to the end of its tail. The teeth of these alligators are long and sharp, ideal for crushing shells. Their fourth lower tooth is bigger than the rest. With its mouth shut, its upper teeth are outside of its lower teeth, which makes it different to crocodiles.
The Chinese alligator was once distributed widely throughout the eastern part of China’s Yangtze River system. Today it is primarily restricted to a reserve of 433 square kilometers in the Anhui province in the lower Yangtze and some parts of the adjacent provinces of Jiangsu and Zhejiang. This species lives in a temperate, subtropical region, in wetlands, swamps, ponds, lakes, freshwater rivers and streams.
Chinese alligators are solitary and hibernate over winter in a system of complex underground burrows, to emerge around May. They use the burrows throughout the year, more in the winter. These can be very elaborate, sometimes housing more than one alligator. On emerging in May, they spend most of their day basking in the sun in order to raise the temperature of their bodies. They are an aquatic species, and can also use water to thermoregulate either by being in the upper columns of water heated up by the sun, or by moving to shaded water to cool down. With their body temperature normalized, they can return to their usual nocturnal ways. A Chinese alligator makes a bellowing sound to communicate its location. Males and females both also use body language for communication, such as using their lower jaws to slap the water or snapping their jaws to convey a warning.
Chinese alligators are polygynous and males mate with more than one female. Both males and females bellow or roar to signal their location and seek a mate. Both genders also have a musk gland under their lower jaw that produces a scent that is attractive and is used in mating. After mating in June, egg-laying takes place in mid-July. The female makes a mound nest from surrounding mud and vegetation and on land that surrounds lakes or rivers. The nests is often near a burrow, so that during incubation a mother can attend to the nest. She lays 10 - 40 eggs in a hollow on the top of the mound, then covers them with more vegetation. She stays near the nest, and in 70 days the eggs hatch, when the young alligators make a high-pitched croaking sound. Their mother quickly digs them out and looks after them throughout their first winter. They reach maturity after 5 - 7 years.
Habitat destruction is the primary threat to this species. Wetland areas are developed for agriculture in order to cope with the huge human population increase in the region. This animal now mainly lives in populated areas where inevitably it comes into conflict with the local farmers. The burrow systems where they hibernate cause problems for drainage in fields, and alligators also eat the farmers' ducks. Despite the lack of commercial value on the international market for the skin of the Chinese alligator, often these reptiles are killed when encountered, due to either fear or a threat to livelihood.
According to the Wikipedia resource, the total Chinese alligator population size is approximately 150 individuals in the wild and more than 10,000 in captivity. Currently this species is classified as Critically Endangered (CR) on the IUCN Red List.