Reptiles of alligator sinensis. Also known as catfish, it is a smaller crocodile. It is characterized by a short and blunt kiss and belongs to the alligator. It is about 2 meters long. Live by rivers and lakes, dig holes for a living. It hibernates for half a year, from June 10 to March and wakes up in mid-April. Mainly go out for food at night and sometimes go out to bask in the sun during the day. Feeding on fish, frogs, birds, rats, etc. After mating in June, they build nests and lay eggs, about 20. As a special product in China, it is distributed in the middle and lower reaches of the Yangtze River and around Taihu Lake, and its number is gradually decreasing, and it is listed as a national first-class protected animal. A.mississippien-sis belongs to the same genus as the Chinese alligator, which is found in the Mississippi River in North America, and is the only remaining two species in the Chinese alligator family. At present, their distribution distance is almost half of the earth's circumference, but in Tertiary, they were widely distributed in the old and new continents. It can be seen that the current distribution has the characteristics of residue, which is an example of discontinuous distribution in animal geography.