The crab is ten-legged because it is scientifically categorized as belonging to the decapod order of the arthropod Mollusca.

In biological taxonomy, it is in the same class as shrimp, lobster, and hermit crabs.

Most species of crabs live in or near the sea, with some in freshwater or on land. They rely on their mother crabs to give birth to their young, and each time she lays many eggs, which can number millions or more. Crabs rely on geomagnetic fields for orientation. These organisms have a complex and highly variable amount of genetic material, often upwards of 100 pairs.

Common crabs include hairy crabs (river crabs, hairy crabs, clear-water crabs) and pike crabs. China's crab resources are very rich, with the lower reaches of the Yangtze River, Gucheng Lake hairy crabs, Taihu Lake hairy crabs, Gaoyou Lake hairy crabs, Yangcheng Lake hairy crabs, Crab House hairy crabs, Xinghua hairy crabs, and Hongze Lake hairy crabs produced by the hairy crabs for the top quality.

Extended information:

The crab is very nutritious, with protein content several times higher than that of pork, fish, etc., as well as higher levels of calcium, phosphorus, iron and vitamin A. The crab has a very good nutritional value, with a protein content several times higher than that of pork and fish.

According to nutritional tests on crab meat, the protein content of 100 grams of crab meat is about 15 to 18 percent by fresh weight, while the water content is about 80 percent, and the protein content of crab meat is as high as 90 percent by dry weight. Even if the crab yolk and other parts are counted, the proportion of protein in the dry weight is also as high as 70 percent or more.

So, if you consume a lot of crab meat, the demand for protease in the digestive tract will be great. If you eat less protein food on weekdays and the protease is not working too hard, suddenly eating in a large amount of crab meat can be quite a challenge for the digestive system.

Crab meat is relatively rich in magnesium and high in calcium. The calcium content in river crabs, for example, exceeds the levels found in milk, with some varieties able to go as high as 200mg/100g or more. In addition, the crab's content of zinc, selenium, iodine and other trace elements is also quite high, especially selenium, which is much higher than the level of ordinary meat.

From a vitamin point of view, the crab's vitamin A content is relatively commendable, up to 1.5 to 2 times that of an egg, but almost all of it is found in the yolk portion of the crab, while the amount in the white crab meat is almost negligible. Its levels of B vitamins are not much different from those of most fish, with lower levels of vitamin B1 than in meat foods, and slightly higher levels of vitamin B2, but also found mainly in the yolk portion of the crab, with lower levels in the white meat.

Crab meat contains higher levels of cholesterol than meat and is close to the level of animal offal such as liver.

Baidu Encyclopedia - Crab

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