There is a pyramid-shaped part at the bottom of the male crab, which is the male crab.
The bottom of the female crab is oval and big. If it's this shape, it's a female crab.
Extended data:
Crab (páng xiè): Animal kingdom, Arthropoda, Crustacea, Soft Crustacea, True soft armor Subclass, Decapoda, Gastropoda, Anura. It is a crustacean. Its body is protected by a hard shell and breathes through its gills. Taxonomically, it is the same kind of animal as shrimp, lobster and hermit crab.
Most kinds of crabs live in the ocean or offshore areas, and some live in fresh water or land. They rely on the mother crab to give birth to small crabs, and every time the mother crab will lay a large number of eggs, the number can reach more than one million. Crabs rely on the geomagnetic field to judge their own direction. The amount of genetic material of this kind of organism is complex and varies greatly, often as many as 100 pairs.
Common crabs are hairy crabs (river crabs, hairy crabs, clear water crabs) and swimming crabs. China is rich in crab resources, among which the hairy crabs produced in Gucheng Lake, Taihu Lake, gaoyou lake, Yangcheng Lake, Xiefu, Xinghua and Hongze Lake in the lower reaches of the Yangtze River are the top grade.
2018 March 15, CCTV 3. 15 party's first consumption warning was released. Arsenic in crabs and tomatoes will not be converted into arsenic in human gastric juice.
References:
Baidu encyclopedia-crab