Appearance differences 1. Blue crab: The carapace and appendages of blue crabs are green-edged. The carapace is smooth and slightly raised, with an obvious "H"-shaped indentation on the back. There are four protruding triangular teeth on the carapace of the head and eyes. Crabs come in various sizes and have spines. Hairy crab: The back shell of hairy crab is blue and the belly is white, slightly yellow or brown. The claw tips of Yangcheng Lake hairy crabs are golden yellow, and their claws are powerful and can crawl freely on the surface of floor tiles. The claws of Chinese hairy crabs have short, fine hairs. Difference in fullness 2: Blue crab: The fullness of blue crab is easy to judge because blue crab is a kind of meat crab. Even small blue crabs are full of meat, so as long as the weight reaches a certain level, the blue crabs are full. Hairy Crab: Hairy crab is a crab whose meat is easy to judge the fullness of. Just press the thinnest leg of the hairy crab. If it feels full, it means the meat is filling. If it is empty, it means the hairy crab meat is not full enough. Differences in sexual maturity 3. Blue crabs: In areas with suitable temperatures, blue crabs will enter sexual maturity as long as a single head reaches a certain weight, so there will be sexual maturity all year round. Hairy crabs: The sexual maturity period of hairy crabs is in September of the lunar calendar every year. Nine females and ten males say that crab roe and hairy crabs are eaten in the ninth month of the lunar calendar. Usually the belly of hairy crabs with crab roe will be slightly yellow and feel full and transparent. Nutritional differences between blue crabs: Blue crabs are rich in protein, some carbohydrates are the source of the sweet taste of blue crabs, and some unsaturated fatty acids. At the same time, the content of vitamin A, carotene and minerals is also high. Hairy crab: The protein and fat content of hairy crab is higher than that of blue crab, but the carbohydrate content is lower than that of blue crab. The mineral content is also high, mainly the vitamin and carotene content is lower than that of blue crab.