Naturally growing river crabs are generally burrowers or hermits. When food is plentiful and full, they often live in burrows to avoid enemies. When there are no burrowing conditions, they hide in the gravel or grass. River crabs usually like to live in clean water, abundant water plants in the rivers and lakes, in the pond, they are often hidden in the silt at the bottom of the pond. River crabs come out day and night, settle down when the bait is abundant and the environment is suitable, and abandon their burrows once they are mature. River crabs grow in freshwater and reproduce in seawater. After entering freshwater, crab fry generally live in bait-rich rivers and lakes for about 18 months, and their gonads gradually mature. Mature river crabs start to spawn in the offshore area where sea and freshwater mix in late fall and early winter, which is the reproductive migration. Female crabs can lay eggs soon after mating, and the eggs are attached to the hairs of the abdominal limbs of the females in bunches, piling up in the abdomen until the larvae hatch. This type of crab is called "egg-holding crab". River crabs can produce tens of thousands to millions of eggs at a time, and can produce 2-3 times. In nature, fertilized eggs take up to 4 months to emerge, and the hatching rate can be as high as 90%. The newly hatched larvae are small and shaped like water fleas, called flea-like larvae. The flea-like larvae molt five times and grow into crab fry (large-eyed larvae) in about 35 days, which molt once more to become juvenile crabs. The crab that has just shed its shell is called soft-shelled crab, which is incapable of feeding and defending itself against enemies, and its shell is hardened only after 1-2 days, at which time it is gradually active, and its body increases significantly after shedding its shell. The body of the river crab ages and dies soon after breeding. River crab's diet is very mixed, it meat and vegetarian food, and like to eat fish, shrimp, snails, worms, earthworms, insects and their young early animal food, but also eat injured or just moulted of the same kind, holding the egg crab in the hungry, but also to take the eggs as food. In the natural environment, river crabs can easily get the water plants, so the plant food is mainly. River crabs are very voracious and have a large appetite and strong digestive ability. When food is abundant, they can eat a lot, and when there is no food, they will not starve to death even if they don't eat for a few days or even a month. This is because they will store the excess nutrients in the liver after they are full of food, and the "soft-shelled crabs" just shedding their shells are the nutrients stored beforehand to maintain their lives. During the overwintering period in the cave, it stops or reduces feeding. River crabs are not only gluttonous, but also have the habit of fighting for food. In order to compete for a meal, often kill each other